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Sample records for doppler ultrasound scan

  1. Doppler ultrasound monitoring technology.

    PubMed

    Docker, M F

    1993-03-01

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

  2. 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

  3. Applications of Doppler ultrasound during labor.

    PubMed

    Mihu, Dan; Diculescu, Doru; Costin, Nicolae; Mihu, Carmen Mihaela; Blaga, Ligia; Ciortea, Răzvan; Măluţan, Andrei

    2011-06-01

    The information provided by Doppler ultrasound examination during labor permits the understanding of the mechanisms regarding the physiology and pathophysiology of feto-placental exchange and the fetal adaptive systems. There are certain technical difficulties related to intrapartum Doppler ultrasound examination. The investigated sites are the uterine arteries, umbilical arteries, fetal circulation. In diastole, when intrauterine pressure exceeds maternal diastolic pressure, the perfusion pressure of the uterine artery blood flow is no longer present. A progressive decrease in the diastolic component is seen along with an increase in intrauterine pressure from 10 to 60 mmHg. During premature birth or preeclampsia, there are particular changes in the uterine blood flow. A remarkable stability of the umbilical resistance index is found during labor, which shows the permanent presence of feto-placental exchange. Certain correlations can be established between fetal heart rate changes in labor and Doppler ultrasound aspects at the level of umbilical arteries. Doppler examination confirms the concept of reduced cerebral blood flow by the compression of the fetal skull as a cause of decelerations occurring during labor. The decision regarding the extraction of the fetus can only be made by correlating the results of Doppler ultrasound with the other paraclinical methods for the monitoring of the intrapartum fetal status.

  4. [Doppler ultrasound of penis arteries].

    PubMed

    Jünemann, K P; Siegsmund, M; Löbelenz, M; Alken, P

    1990-05-01

    In addition to pharmaco testing, pharmaco-Doppler sonography of the penile arteries is part of the basic work-up for erectile dysfunction. Insufficient training with the Doppler method, lack of standardized criteria for evaluation of the penis, and analysis of the Doppler curves all make it difficult to use Doppler sonography for the evaluation of impotent men. The aim of this study was to explain the principal criteria of the method and demonstrate the most important details for analyzing the form of the Doppler waves. Pharmaco-Doppler sonography includes the evaluation of blood-flow velocities within the dorsal and deep cavernous arteries of the penis before and after intracavernous application of a vasoactive drug. The following main criteria have proven to be most important for analysis of the Doppler curves: evaluation of the amplitude height, the actual wave form, differences between the left and right arteries and along the individual vessel, amplitude increase, and elevation of the curve baseline after pharmaco stimulation. The most frequent mistakes made during evaluation of the penile arteries are changes in the probe angle, pressure put on the artery by the probe during evaluation and a false estimation of the evaluation time after pharmaco stimulation. Recently, duplex sonography of the penile arteries has been introduced, and this method allows an accurate measurement of the blood-flow velocity and arterial diameter changes before and after application of the drug. Furthermore, additional calculation of the resistancy index permits determination of the vascular resistance and optimizes the evaluation of the penile arterial status. The technical details, the method, and the analyzation criteria are all explained in detail.

  5. Applications of Doppler ultrasound in clinical vascular disease

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

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

  6. 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

  7. 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

  8. Superharmonic microbubble Doppler effect in ultrasound therapy.

    PubMed

    Pouliopoulos, Antonios N; Choi, James J

    2016-08-21

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

  9. Superharmonic microbubble Doppler effect in ultrasound therapy.

    PubMed

    Pouliopoulos, Antonios N; Choi, James J

    2016-08-21

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

  10. Breast ultrasound scans - surgeons' expectations.

    PubMed

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

    2015-06-01

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

  11. Early diagnosis of conjoined twins using two-dimensional color Doppler and three-dimensional ultrasound.

    PubMed Central

    Bonilla-Musoles, F.; Raga, F.; Bonilla, F.; Blanes, J.; Osborne, N. G.

    1998-01-01

    Transvaginal three-dimensional (3-D) and color Doppler ultrasound were used to establish a first-trimester definitive diagnosis and classification of thoracoomphalopagus conjoined twins following two-dimensional (2-D) transabdominal and transvaginal scans that indicated twin gestation of uncertain classification. Color Doppler in combination with 3-D ultrasound can be a useful complement to 2-D ultrasound to confirm early diagnosis and determine the extent of organ sharing and definitive classification of conjoined twins. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:9770956

  12. Detection of microemboli by transcranial Doppler ultrasound.

    PubMed Central

    Grosset, D G; Georgiadis, D; Kelman, A W; Cowburn, P; Stirling, S; Lees, K R; Faichney, A; Mallinson, A; Quin, R; Bone, I; Pettigrew, L; Brodie, E; MacKay, T; Wheatley, D J

    1996-01-01

    Doppler ultrasound detection of abnormally high-pitched signals within the arterial waveform offers a new method for diagnosis, and potentially for prediction, of embolic complications in at-risk patients. The nature of Doppler "microembolic" signals is of particular interest in patients with prosthetic heart valves, where a high prevalence of these signals is observed. Monitoring the middle cerebral artery with 2-MHz transcranial Doppler ultrasound (TC-2000, Nicolet Biomedical; Warwick, UK), we looked for microemboli signals in 150 patients (95 women and 55 men), and found 1 or more signals during a 30-min recording in 89% of 70 patients with Bjork-Shiley valves (principally monostrut), 54% of 50 patients with Medtronic-Hall valves, and 50% of 30 patients with Carpentier-Edwards valves (p < 0.001, chi 2). In the patients with Bjork-Shiley valves, the mean number of signals per hour was 59 (range, 42-86; 95% confidence interval), which was significantly higher than the mean in patients with Medtronic-Hall and Carpentier-Edwards valves (1.5[range, 0.5-2.5] and 1 [range, 0-5.3], respectively; both p < 0.04, multiple comparisons. Bonferroni correction). In the patients undergoing serial pre- and postoperative studies, the causative role of the valve implant was emphasized. There was no correlation between the number of emboli signals and a prior history of neurologic deficit, cardiac rhythm, previous cardiac surgery, or the intensity of oral anticoagulation, in patients with prosthetic heart valves. In Bjork-Shiley patients, dual (mitral and aortic) valves were associated with more signals than were single valves. In Medtronic-Hall patients, the signal count was greater for valves in the aortic position than it was for valves in the mitral position. Comparative studies of Doppler emboli signals in other clinical settings suggest a difference in composition or size of the underlying maternal between prosthetic valve patients and patients with carotid stenosis. These

  13. Embolic Doppler ultrasound signal detection via fractional Fourier transform.

    PubMed

    Gençer, Merve; Bilgin, Gökhan; Aydın, Nizamettin

    2013-01-01

    Computerized analysis of Doppler ultrasound signals can aid early detection of asymptomatic circulating emboli. For analysis, physicians use informative features extracted from Doppler ultrasound signals. Time -frequency analysis methods are useful tools to exploit the transient like signals such as Embolic signals. Detection of discriminative features would be the first step toward automated analysis of embolic Doppler ultrasound signals. The most problematic part of setting up emboli detection system is to differentiate embolic signals from confusing similar wave-like patterns such as Doppler speckle and artifacts caused by tissue movement, probe tapping, speaking etc. In this study, discrete version of fractional Fourier transform is presented as a solution in the detection of emboli in digitized Doppler ultrasound signals. An accurate set of parameters are extracted using short time Fourier transform and fractional Fourier transform and the results are compared to reveal detection quality. Experimental results prove the efficiency of fractional Fourier transform in which discriminative features becomes more evident.

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

    PubMed

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

    2015-02-01

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

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

    PubMed Central

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

    2015-01-01

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

  16. Doppler photoacoustic and Doppler ultrasound in blood with optical contrast agent

    NASA Astrophysics Data System (ADS)

    Sheinfeld, Adi; Eyal, Avishay

    2013-03-01

    Photoacoustic Doppler flowmetry as well as Doppler ultrasound were performed in acoustic resolution regime on tubes filled with flowing blood with indocyanine green (ICG) at different concentrations. The photoacoustic excitation utilized a pair of directly-modulated fiber-coupled 830nm laser-diodes, modulated with either CW or tone-bursts for depthresolved measurements. The amplitude of the Doppler peak in photoacoustic Doppler measurements was found to be proportional to the ICG concentration. Photoacoustic Doppler was measured in ICG at human safe concentrations, but not in whole blood. Comparing the results between the two modalities implied that using a wavelength with higher optical absorption may improve the photoacoustic signal in blood.

  17. A digital multigate Doppler method for high frequency ultrasound.

    PubMed

    Qiu, Weibao; Ye, Zongying; Yu, Yanyan; Chen, Yan; Chi, Liyang; Mu, Peitian; Li, Guofeng; Wang, Congzhi; Xiao, Yang; Dai, Jiyan; Sun, Lei; Zheng, Hairong

    2014-01-01

    Noninvasive visualization of blood flow with high frequency Doppler ultrasound has been extensively used to assess the morphology and hemodynamics of the microcirculation. A completely digital implementation of multigate pulsed-wave (PW) Doppler method was proposed in this paper for high frequency ultrasound applications. Analog mixer was eliminated by a digital demodulator and the same data acquisition path was shared with traditional B-mode imaging which made the design compact and flexible. Hilbert transform based quadrature demodulation scheme was employed to achieve the multigate Doppler acquisition. A programmable high frequency ultrasound platform was also proposed to facilitate the multigate flow visualization. Experimental results showed good performance of the proposed method. Parabolic velocity gradient inside the vessel and velocity profile with different time slots were acquired to demonstrate the functionality of the multigate Doppler. Slow wall motion was also recorded by the proposed method.

  18. Photoacoustic and high-frequency power Doppler ultrasound biomicroscopy: a comparative study

    NASA Astrophysics Data System (ADS)

    Jiang, Yan; Harrison, Tyler; Ranasinghesagara, Janaka; Zemp, Roger J.

    2010-09-01

    Both photoacoustic imaging and power Doppler ultrasound are capable of producing images of the vasculature of living subjects, however, the contrast mechanisms of the two modalities are very different. We present a quantitative and objective comparison of the two methods using phantom data, highlighting relative merits and shortcomings. An imaging system for combined photoacoustic and high-frequency power Doppler ultrasound microscopy is presented. This system uses a swept-scan 25-MHz ultrasound transducer with confocal dark-field laser illumination optics. A pulse-sequencer enables ultrasonic and laser pulses to be interlaced so that photoacoustic and power Doppler ultrasound images can be coregistered. Experiments are performed on flow phantoms with various combinations of vessel size, flow velocity, and optical wavelength. For the task of blood volume detection, power Doppler is seen to be advantageous for large vessels and high flow speeds. For small vessels with low flow speeds, photoacoustic imaging is seen to be more effective than power Doppler at the detection of blood as quantified by receiver operating characteristic analysis. A combination of the two modes could provide improved estimates of fractional blood volume in comparison with either mode used alone.

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

    PubMed

    Gittins, John; Martin, Kevin

    2010-04-01

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

  20. Intralaparoscopic ultrasound and Doppler sonography in urology.

    PubMed

    Trombetta, C; Liguori, G; Savoca, G; Siracusano, S

    1996-01-01

    Common practice with intraoperative sonography during open surgery has demonstrated that ultrasounds supply important information that can help the urologist in decision making; in addition, the growing popularity of laparoscopy has underscored the importance of laparoscopic ultrasonography. Laparoscopic ultrasound combines the advantage of diagnostic laparoscopy and intraoperative contact ultrasonography. The authors report their experience with intralaparoscopic ultrasonography using a 7.5-MHz transesophageal probe in several paradigmatic urologic applications, in which intraoperative ultrasonography was employed to provide anatomical information, to supply efficiency in confirming and excluding anticipated or unexpected pathology, and to solve diagnostic problems using high-resolution, real-time, B-mode ultrasound. Intralaparoscopic ultrasound proves to be a simple, efficient procedure that provides useful information in order to help the urologist in intraoperative decision making.

  1. [Peroperative ultrasound scanning of the pancreas].

    PubMed

    Alexandre, J H; Hernigou, A; Billebaud, T; Bouillot, J L; Plainfosse, M C

    1985-01-01

    Intraoperative realtime high resolution ultrasound scanning of the pancreas seems to be a new and promising procedure. We have performed it in 28 patients: the normal ultrasound picture of pancreatic ducts and parenchyma was defined in 9 patients without pancreatic disease; in 19 patients with pancreatic disease, intraoperative ultrasound was compared with preoperative ultrasound examination. Seven of 8 patients with pancreatic carcinoma and 4 of 6 with calcifying chronic pancreatitis had positive findings, respectively. In 3 cancer patients, intraoperative ultrasound investigation avoided a long and unavailing dissection of the tumor by revealing extensive spread. In selected cases, intraoperative sonography allowed to characterize and to localize pancreatic carcinoma: portal vein invasion, relationship of the tumor to the duct of Wirsung and small hepatic metastases. In chronic pancreatitis, intraoperative ultrasound information concerning the dimensions of the pancreatic duct, the structure and the localization of pseudocysts was comparable to that obtained by radiological opacification. Furthermore, intraoperative ultrasound exploration guided proper incision and evacuation of pancreatic pseudocysts in two patients. Operative ultrasound seems to us to be mandatory during pancreatic surgery. Further experience with this technique is needed in a larger number of patients. However, we believe that it could replace intraoperative cholangiography and pancreaticography in the assessment of extension and complications of pancreatic disease.

  2. Improving cranial ultrasound scanning strategy in neonates

    PubMed Central

    Bray, Lisa

    2016-01-01

    Cranial ultrasound scans are undertaken in this tertiary neonatal intensive care unit by the doctors within the department. A quality improvement project was undertaken by means of two PDSA cycles to determine adherence to neonatal cranial ultrasound scanning schedule, assess the quality of scan reporting, and formulate a comprehensive guideline outlining best practice. The baseline measurements assessed 93 scans of preterm infants and 9 of term infants. The results of this prompted intradepartmental education (PDSA cycle 1) then creation and implementation of a documentation template, a local guideline, and education via presentations, posters, and email (PDSA cycle 2). These encompassed 77 preterm and 5 term scans. In our baseline measurements, 52% of preterm infant scans and 44% of term infant scans were performed to schedule. Of premature baby scan reports, 75% had the time documented and 92% the name of the scanning doctor. After implementing changes PDSA cycle 2 data showed that 74% of preterm infant scans and all term infant scans were performed according to schedule, with 100% having the doctor's name and time of scan documented. We successfully introduced a guideline and documentation template, improving performance to schedule and documentation in most areas. It remains an ongoing challenge to adhere to basic standards of documentation; a template can assist in achieving this. Rotating trainees may offer insight into areas that could benefit from quality improvement. This enthusiasm can be successfully harnessed to implement changes to improve quality of patient care. PMID:27096095

  3. Live ultrasound volume reconstruction using scout scanning

    PubMed Central

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

    2015-01-01

    INTRODUCTION Ultrasound-guided interventions often necessitate scanning of deep-seated anatomical structures that may be hard to visualize. Visualization can be improved using reconstructed 3D ultrasound volumes. High-resolution 3D reconstruction of a large area during clinical interventions is challenging if the region of interest is unknown. We propose a two-stage scanning method allowing the user to perform quick low-resolution scouting followed by high-resolution live volume reconstruction. METHODS Scout scanning is accomplished by stacking 2D tracked ultrasound images into a low-resolution volume. Then, within a region of interest defined in the scout scan, live volume reconstruction can be performed by continuous scanning until sufficient image density is achieved. We implemented the workflow as a module of the open-source 3D Slicer application, within the SlicerIGT extension and building on the PLUS toolkit. RESULTS Scout scanning is performed in a few seconds using 3 mm spacing to allow region of interest definition. Live reconstruction parameters are set to provide good image quality (0.5 mm spacing, hole filling enabled) and feedback is given during live scanning by regularly updated display of the reconstructed volume. DISCUSSION Use of scout scanning may allow the physician to identify anatomical structures. Subsequent live volume reconstruction in a region of interest may assist in procedures such as targeting needle interventions or estimating brain shift during surgery. PMID:26005249

  4. Live ultrasound volume reconstruction using scout scanning

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  5. Scanning phononic lattices with ultrasound

    SciTech Connect

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

    1999-11-01

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

  6. Ultrasound scanning of the ovarian cycle.

    PubMed

    Hackelöer, B J

    1984-12-01

    Ultrasound scanning of the ovarian cycle is a simple noninvasive technique for monitoring ovarian activity. It helps to predict a mature follicle and the time of ovulation more accurately than the basal body temperature and more rapidly and cheaply than a hormone profile, but still only one facet of ovarian activity. With respect to in vitro fertilization, egg collection can be undertaken by means of sonically guided puncture via the bladder, which is reported later in this issue. Replacement of the embryo can be controlled by sonar visualization of catheter. The use of ultrasound has proved to be extremely helpful in the management of the infertile couple.

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

    ERIC Educational Resources Information Center

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

    2012-01-01

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

  8. Breast ultrasound scans – surgeons’ expectations

    PubMed Central

    Bednarski, Piotr; Chrapowicki, Eryk; Jakubowski, Wiesław

    2015-01-01

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

  9. Probabilistic neural networks employing Lyapunov exponents for analysis of Doppler ultrasound signals.

    PubMed

    Ubeyli, Elif Derya

    2008-01-01

    The implementation of probabilistic neural networks (PNNs) with the Lyapunov exponents for Doppler ultrasound signals classification is presented. This study is directly based on the consideration that Doppler ultrasound signals are chaotic signals. This consideration was tested successfully using the nonlinear dynamics tools, like the computation of Lyapunov exponents. Decision making was performed in two stages: computation of Lyapunov exponents as representative features of the Doppler ultrasound signals and classification using the PNNs trained on the extracted features. The present research demonstrated that the Lyapunov exponents are the features which well represent the Doppler ultrasound signals and the PNNs trained on these features achieved high classification accuracies. PMID:17709103

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

    ERIC Educational Resources Information Center

    Looker, T.

    1985-01-01

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

  11. Photoacoustic and Doppler ultrasound for oxygen consumption estimation: implementation on a clinical array system

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

    Recently, we have developed a combined photoacoustic and high-frequency Doppler ultrasound system with a single element transducer to estimate the metabolic rate of oxygen consumption in small animal models. However, the long scanning time due to mechanical motion may be a limitation of our swept-scan system. In this work, the single element transducer was replaced by a clinical array transducer which may provide more accurate flow velocity estimations, higher frame rates, improved penetration depth, and improved depth-of-field due to dynamic focusing capabilities. We used an array system from Verasonics Inc. which enables flexible pulse-sequence programming and parallel channel data acquisition, along with a pulsed laser and optical parametric oscillator. For flow estimation, we implemented a flash- Doppler sequence which transmits ensembles of plane-wave excitations. Echo signals are beamformed and subjected to wall-filtering and Kasai flow estimation algorithms. High frame rates over a wide region can be achieved. Combined interlaced photoacoustic and Doppler imaging on flow phantoms has been performed on this system. We demonstrate the ability to image animal blood to depths of 1.5-cm with high signal-to-noise with both modalities. The light penetration is 2-cm. We discuss the performance of Doppler flow estimation and photoacoustic oxygen saturation estimation and their role in future work of estimating oxygen consumption.

  12. Suprasternal Doppler ultrasound for assessment of stroke distance

    PubMed Central

    Childs, C; Goldring, S; Tann, W; Hillier, V

    1998-01-01

    An assessment of a non-invasive technique for measurement of stroke distance was made using a portable Doppler ultrasound machine. The aim was to determine the measurement error of repeated stroke distance measurements (within-observer variability) and to assess measurement agreement between two operators (between-observer variability). The measurement error (within-observer variability) for both operators was similar at approximately 2 cm. However, the measurements of the two operators (between-observer variability) did not agree well. Using the mean (SD) of three readings by each operator, the mean difference between the operators was −0.21 cm (1.96) giving a 95% confidence interval for the differences of −4.0 to +3.6 cm. There were significant positive and negative correlations between stroke distance and a variety of variables (age, height, weight, heart rate), but the relations were weak. The results indicate that the Doppler ultrasound technique for measurement of stroke distance would best be used to study trend changes in an individual patient, or subject, by a single operator. 

 PMID:9875022

  13. Intrarenal Doppler ultrasound studies in normal and acutely obstructed kidneys.

    PubMed

    Rodgers, P M; Bates, J A; Irving, H C

    1992-03-01

    Renal ultrasound examinations and intrarenal arterial Doppler studies were performed on 48 patients with normal renal tracts and 20 patients presenting with acute renal colic resulting from ureteric calculus, 14 of whom had urographic evidence of renal obstruction. The mean resistance index (RI) of the Doppler waveforms obtained on the 14 obstructed kidneys (70.4 +/- 6.22) was significantly higher than the mean RI of the 96 normal kidneys (62.4 +/- 6.43). The mean difference between the RIs of the obstructed kidneys and their contralateral non-obstructed kidneys (8.37 +/- 4.43) was also significantly higher than the differences in RI seen between pairs of normal kidneys (2.70 +/- 1.71). Five out of 14 obstructed kidneys showed no pelvicalyceal dilatation and could not have been shown to be obstructed on conventional sonography. Four of these five had RI changes suggestive of obstruction and thus 13 of 14 obstructed kidneys would have been identified as obstructed by a combination of Doppler and conventional sonographic findings. 10 of the 14 obstructed kidneys were re-examined after passage of a urinary calculus and nine showed a reduction in the RI of the previously obstructed kidneys. The 10th subsequently required ureterolithotomy.

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

    PubMed

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

    2014-05-01

    Results from a four-year audit of a Doppler quality assurance (QA) program using a commercially available Doppler string phantom are presented. The suitability of the phantom was firstly determined and modifications were made to improve the reliability and quality of the measurements. QA of Doppler ultrasound equipment is very important as data obtained from these systems is used in patient management. It was found that if the braided-silk filament of the Doppler phantom was exchanged with an O-ring rubber filament and the velocity range below 50 cm/s was avoided for Doppler quality control (QC) measurements, then the maximum velocity accuracy (MVA) error and intrinsic spectral broadening (ISB) results obtained using this device had a repeatability of 18 ± 3.3% and 19 ± 3.5%, respectively. A consistent overestimation of the MVA of between 12% and 56% was found for each of the tested ultrasound systems. Of more concern was the variation of the overestimation within each respective transducer category: MVA errors of the linear, curvilinear and phased array probes were in the range 12.3-20.8%, 32.3-53.8% and 27-40.7%, respectively. There is a dearth of QA data for Doppler ultrasound; it would be beneficial if a multicentre longitudinal study was carried out using the same Doppler ultrasound test object to evaluate sensitivity to deterioration in performance measurements. PMID:24156827

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

    PubMed Central

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

    2013-01-01

    We present a methodology to measure absolute flow velocity using laser-scanning photoacoustic microscopy. To obtain the Doppler angle, the angle between ultrasonic detection axis and flow direction, we extracted the distances between the transducer and three adjacent scanning points along the flow and repeatedly applied the law of cosines. To measure flow velocity along the ultrasonic detection axis, we calculated the time shift between two consecutive photoacoustic waves at the same scanning point, then converted the time shift to velocity according to the sound velocity and time interval between two laser illuminations. We verified our method by imaging flow phantoms. PMID:23825803

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

    PubMed

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

    2004-02-01

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

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

    SciTech Connect

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

    2014-06-15

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

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

    PubMed

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

    2016-01-01

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

  19. Spatiotemporal Clutter Filtering of Ultrafast Ultrasound Data Highly Increases Doppler and fUltrasound Sensitivity.

    PubMed

    Demené, Charlie; Deffieux, Thomas; Pernot, Mathieu; Osmanski, Bruno-Félix; Biran, Valérie; Gennisson, Jean-Luc; Sieu, Lim-Anna; Bergel, Antoine; Franqui, Stéphanie; Correas, Jean-Michel; Cohen, Ivan; Baud, Olivier; Tanter, Mickael

    2015-11-01

    Ultrafast ultrasonic imaging is a rapidly developing field based on the unfocused transmission of plane or diverging ultrasound waves. This recent approach to ultrasound imaging leads to a large increase in raw ultrasound data available per acquisition. Bigger synchronous ultrasound imaging datasets can be exploited in order to strongly improve the discrimination between tissue and blood motion in the field of Doppler imaging. Here we propose a spatiotemporal singular value decomposition clutter rejection of ultrasonic data acquired at ultrafast frame rate. The singular value decomposition (SVD) takes benefits of the different features of tissue and blood motion in terms of spatiotemporal coherence and strongly outperforms conventional clutter rejection filters based on high pass temporal filtering. Whereas classical clutter filters operate on the temporal dimension only, SVD clutter filtering provides up to a four-dimensional approach (3D in space and 1D in time). We demonstrate the performance of SVD clutter filtering with a flow phantom study that showed an increased performance compared to other classical filters (better contrast to noise ratio with tissue motion between 1 and 10mm/s and axial blood flow as low as 2.6 mm/s). SVD clutter filtering revealed previously undetected blood flows such as microvascular networks or blood flows corrupted by significant tissue or probe motion artifacts. We report in vivo applications including small animal fUltrasound brain imaging (blood flow detection limit of 0.5 mm/s) and several clinical imaging cases, such as neonate brain imaging, liver or kidney Doppler imaging.

  20. Scanning laser Doppler vibrometry of the middle ear ossicles.

    PubMed

    Ball, G R; Huber, A; Goode, R L

    1997-04-01

    This paper describes measurements of the vibratory modes of the middle ear ossicles made with a scanning laser Doppler vibrometer. Previous studies of the middle ear ossicles with single-point laser Doppler measurements have raised questions regarding the vibrational modes of the ossicular chain. Single-point analysis methods do not have the ability to measure multiple points on the ossicles and, consequently, have limited ability to simultaneously record relative phase information at these points. Using a Polytec Model PSV-100, detailed measurements of the ossicular chain have been completed in the human temporal bone model. This model, when driven with a middle ear transducer, provides detailed three-dimensional data of the vibrational patterns of the middle ear ossicles. Implications for middle ear implantable devices are discussed.

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

    PubMed

    Ubeyli, Elif Derya

    2008-05-01

    A new approach based on the implementation of the automated diagnostic systems for Doppler ultrasound signals classification with the features extracted by eigenvector methods is presented. In practical applications of pattern recognition, there are often diverse features extracted from raw data which needs recognizing. Because of the importance of making the right decision, the present work is carried out for searching better classification procedures for the Doppler ultrasound signals. Decision making was performed in two stages: feature extraction by the eigenvector methods and classification using the classifiers trained on the extracted features. The aim of the study is classification of the Doppler ultrasound signals by the combination of eigenvector methods and the classifiers. The present research demonstrated that the power levels of the power spectral density (PSD) estimates obtained by the eigenvector methods are the features which well represent the Doppler ultrasound signals and the probabilistic neural networks (PNNs), recurrent neural networks (RNNs) trained on these features achieved high classification accuracies. PMID:18358461

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

    PubMed Central

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

    2015-01-01

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

  3. Segmental Comparison of Peripheral Arteries by Doppler Ultrasound and CT Angiography

    PubMed Central

    Swaminathan, Ram Kumar; Ganesan, Prakash; Mayavan, Manibharathi

    2016-01-01

    Introduction Diseases of peripheral arterial system are one of the common causes of limb pain, especially in elderly patients. Here we analyse non invasive imaging of peripheral arterial segments. Aim Aim of the study was to compare arterial diseases of extremities using Doppler ultrasound and CT angiography, and to find the better non-invasive modality of choice. Materials and Methods Fifty patients {14 patients with upper limb complaints (15 upper limbs) and 36 patients with lower limb complaints (72 lower limbs)} of peripheral arterial disease underwent Doppler ultrasound (USG) and CT Angiogram (CTA). Arterial systems divided into anatomic segments and luminal narrowing were compared using gray scale Doppler ultrasound and axial images of arterial phase of CT angiogram. Using statistical methods, sensitivity, specificity and accuracy of Doppler ultrasound and CT angiography were determined. Results Six hundred and nineteen arterial segments were studied with CT angiography and Doppler ultrasound. Of which 226 diseased segments were identified in CT angiography. Doppler overestimated narrowing by one grade in 47 segments, by two grade in 11 segments, by three grades in 30 segments and by four grades in 22 segments; underestimated by one grade in 28 segments, by two grades in 9 segments, by three grades in 5 segments and by four grades in 3 segments. Significant statistical difference exists between Doppler USG and CT angiography. Doppler showed good correlation with CT angiography in 74%, but, Doppler overestimated stenosis grade in a significant percentage. The sensitivity, specificity and accuracy of Doppler USG compared with CT angiography was 93.36%, 82.44%, and 86.42%. Conclusion Duplex Doppler can be the first investigation in excluding peripheral arterial disease, especially for evaluation of infra inguinal region of lower limbs and from second part of the subclavian artery in upper limbs. PMID:27042556

  4. Shigeo Satomura: 60 years of Doppler ultrasound in medicine.

    PubMed

    Coman, Ioan M; Popescu, Bogdan A

    2015-01-01

    This year we celebrate 60 years since Shigeo Satomura published the first measurements of the Doppler shift of ultrasonic signals from a beating heart. He demonstrated that Doppler signals can be retrieved from heart movements when insonated with 3 MHz ultrasonic waves. Later, togheter with Ziro Kaneko, he constructed the first Doppler flowmeter to measure the blood flow velocities in peripheral and extracranial brain-supplying vessels using ultrasounds. They proved that ultrasonic Doppler signals from arteries and veins can be recorded from the surface of the skin and pioneered transcutaneous flow analysis in systole and diastole in both normal and diseased blood vessels. These were the first medical applications of Doppler sonography and impressive technologic innovations have been continuing ever since. Over time, Doppler techniques became a key player in diagnostic ultrasound for hemodynamic assessment, replacing cardiac catheterization in many clinical settings. PMID:26699126

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

    PubMed

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

    2010-09-01

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

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

    PubMed

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

    2014-01-01

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

  7. Doppler ultrasound evaluation of transjugular intrahepatic portosystemic shunt function: pitfalls and artifacts.

    PubMed

    Wachsberg, Ronald H

    2003-09-01

    The current literature reflects controversy regarding the accuracy of Doppler ultrasound for the detection of transjugular intrahepatic portosystemic shunt (TIPS) malfunction. Experience has revealed many pitfalls and artifacts that can potentially interfere with the proper performance and interpretation of Doppler studies in patients with TIPS. In this article the author discusses and illustrates the spectrum of pitfalls that may be encountered during Doppler evaluation of TIPS function. PMID:14571161

  8. [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.

  9. Randomised trial of umbilical arterial catheter position: Doppler ultrasound findings.

    PubMed

    Kempley, S T; Gamsu, H R

    1992-07-01

    Umbilical arterial catheters (UAC) were randomly assigned in 69 infants to a high (n = 36) or to a low (n = 33) position. Serial Doppler ultrasound measurements of blood flow velocity in their superior mesenteric arteries, coeliac axis, renal arteries, and anterior cerebral arteries were then obtained. There were no differences in blood flow velocity between high and low UAC groups on days 1, 3, and 7. At 2 weeks, those infants with a high UAC still in place had significantly higher velocities in the mesenteric artery than those infants who had no catheter in place. Infants with high UACs remaining in place for more than 7 days were found to have an increase in abdominal distension and tenderness, whereas this was not the case for those with low UACs. Catheter position has no effect on visceral blood flow if the UAC stays in place for one week or less, whereas prolonged use of a high UAC may alter intestinal blood flow and increase the incidence of abdominal symptoms.

  10. 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.

  11. Wind Measurements from Arc Scans with Doppler Wind Lidar

    SciTech Connect

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

    2015-11-25

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

  12. Wind Measurements from Arc Scans with Doppler Wind Lidar

    DOE PAGESBeta

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

    2015-11-25

    When defining optimal scanning geometries for scanning lidars for wind energy applications, we found that it is still an active field of research. Our paper evaluates uncertainties associated with arc scan geometries and presents recommendations regarding optimal configurations in the atmospheric boundary layer. The analysis is based on arc scan data from a Doppler wind lidar with one elevation angle and seven azimuth angles spanning 30° and focuses on an estimation of 10-min mean wind speed and direction. When flow is horizontally uniform, this approach can provide accurate wind measurements required for wind resource assessments in part because of 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

  13. 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.

  14. Scanning Doppler Lidar Measurements for Wind Energy Applications

    NASA Astrophysics Data System (ADS)

    Frehlich, R.; Kelley, N.

    2008-12-01

    The development of wind energy has increased rapidly along with the size and capacity of wind turbines. These larger machines require detailed wind resource measurements at higher and higher altitudes. Accurate wind speed, wind direction, and turbulence statistics are required for wind resource assessment and efficient wind farm operation. Tower measurements are limited in coverage and do not provide the three dimensional sampling of the atmospheric processes required for accurate model initialization or resource assessment. Remote sensing measurements are the most attractive option for wind energy meteorology. However, the measurement volume must be sufficiently small to resolve the important atmospheric scales and the spatial and temporal measurement domain must satisfy the requirements of the wind energy industry. High resolution profiles of mean and turbulent statistics of the wind field upstream of a wind farm can be produced using a scanning Doppler lidar. Careful corrections for the spatial filtering of the wind field by the lidar pulse produce turbulence estimates equivalent to point sensors but with the added advantage of a larger sampling volume to increase the statistical accuracy of the estimates. For a well designed lidar system, this permits accurate estimates of the mean windspeed and the turbulent statistics over various subdomains and with sufficiently short observation times to monitor rapid changes in conditions. These features may be ideally suited for optimal operation of wind farms and for improved data assimilation for local high resolution forecast models. Results from the analysis of scanning Doppler lidar data collected at the National Renewable Energy Laboratory (NREL) will be presented to highlight some of the fundamental atmospheric processes for wind power meteorology. The unresolved issues for future applications of this technology will be outlined.

  15. 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

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

    PubMed

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

    2006-02-01

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

  17. Combining eigenvector methods and support vector machines for detecting variability of Doppler ultrasound signals.

    PubMed

    Ubeyli, Elif Derya

    2007-05-01

    In this paper, the multiclass support vector machines (SVMs) with the error correcting output codes (ECOC) were presented for detecting variabilities of the multiclass Doppler ultrasound signals. The ophthalmic arterial (OA) Doppler signals were recorded from healthy subjects, subjects suffering from OA stenosis, subjects suffering from ocular Behcet disease. The internal carotid arterial (ICA) Doppler signals were recorded from healthy subjects, subjects suffering from ICA stenosis, subjects suffering from ICA occlusion. Methods of combining multiple classifiers with diverse features are viewed as a general problem in various application areas of pattern recognition. Because of the importance of making the right decision, better classification procedures for Doppler ultrasound signals are searched. Decision making was performed in two stages: feature extraction by eigenvector methods and classification using the SVMs trained on the extracted features. The research demonstrated that the multiclass SVMs trained on extracted features achieved high accuracy rates. PMID:17289211

  18. A scanning laser Doppler vibrometer for modal testing

    SciTech Connect

    Sriram, P.; Craig, J.I.; Hanagud, S. )

    1990-07-01

    Accelerometers are widely used to sense structural response in modal testing. The mass loading and local effects due to accelerometers are not always negligible. The laser Doppler velocimeter/vibrometer (LDV) is a noncontact optical sensing tool for accurately measuring point velocities. The noncontact nature of the instrument makes it particularly attractive for use on lightweight structures where measurement interaction must be minimized. Real-time scanning LDV's have recently been introduced to measure fluid flow velocity profiles rapidly. In this paper, the development of a real-time scanning LDV for structural applications is described. The instrument can be used to simultaneously measure the velocity response at a series of locations on a vibrating structure. Standard modal analysis techniques can then be applied to extract the usual modal data, e.g., natural frequencies, damping and mode shapes. The special case of beam vibration is considered in this paper though the technique can be readily extended to generic planar measurements. The measurement technique has been validated through modal testing of a simple beam structure. Comparisons between theoretical and LDV measured mode shapes and natural frequencies are presented. 20 refs.

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  20. 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.

  1. 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.

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

    PubMed

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

    2016-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  5. 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…

  6. Real-time digital processing of Doppler ultrasound signals and calculation of flow parameters.

    PubMed

    Schlindwein, F S; Vieira, M H; Vasconcelos, C F; Simpson, D M

    1994-01-01

    Vascular diseases and their complications are responsible for around 27% of deaths in Brazil. Doppler ultrasound is a non-invasive technique that has been used to study blood flow in intact blood vessels since Satomura first reported the potential of the technique in 1959. Because it is non-invasive it makes sequential studies and those in normals feasible. Whereas in contrast angiography only vessel anatomy is displayed, Doppler ultrasound produces dynamic information on blood-flow. It may be used to estimate flow-rates, to image regions of blood flow (colour Doppler), and to help in locating sites of arterial disease, thus complementing X-ray examinations. This paper describes a system based on a Digital Signal Processor for real-time spectrum analysis of Doppler ultrasound signals, real-time display of sonograms, and calculation and analysis of three parameters of clinical interest derived from the Doppler signal. The system comprises a TMS320C25 development board, which acquires the signal and performs spectrum analysis, and a microcomputer, which reads the spectral estimates, displays them as a sonogram in real-time and calculates a set of spectral parameters proposed in the literature. The system permits a maximum sampling frequency of 40.96 kHz, and in the sonogram, 80 power spectra per second (each with 128 frequency bins) are displayed. In a preliminary study, the stability of the haemodynamic parameters and their dependence on a user-defined threshold value is investigated.

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

    PubMed Central

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

    2015-01-01

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

  8. Detection of a lumbar foraminal venous varix by Color Doppler Ultrasound.

    PubMed

    Darrieutort-Laffite, Christelle; Desal, Hubert; Berthelot, Jean-Marie; Le Goff, Benoît

    2016-07-01

    Ultrasonography is currently widely used in the rheumatology practice. Although mainly performed to study peripheral joint, several articles have underlined its interest to study spinal anatomy. However, its ability to provide diagnostic features is unknown. We studied the case of a 25-year-old woman having low back pain. Three different imaging modalities (Computed Tomography [CT], Magnetic Resonance Imaging [MRI] and Ultrasound) were used to explore it. CT and MRI showed a foraminal dilation of the lombo-ovarian vein at the L3-L4 level with a scalloping of the lateral edge of L3. We were able to detect it with Color Doppler Ultrasound and a malformation of the inferior vena cava was also found. We showed for the first time that Color Doppler Ultrasound can detect venous malformation of the spine. This imaging modality could help us in the diagnosis of atypical lesions of the spine to confirm their vascular origin. PMID:27068620

  9. Scanning laser ultrasound and wavenumber spectroscopy for in-process inspection of additively manufactured parts

    NASA Astrophysics Data System (ADS)

    Koskelo, EliseAnne C.; Flynn, Eric B.

    2016-04-01

    We present a new in-process laser ultrasound inspection technique for additive manufacturing. Ultrasonic energy was introduced to the part by attaching an ultrasonic transducer to the printer build-plate and driving it with a single-tone, harmonic excitation. The full-field response of the part was measured using a scanning laser Doppler vibrometer after each printer layer. For each scan, we analyzed both the local amplitudes and wavenumbers of the response in order to identify defects. For this study, we focused on the detection of delamination between layers in a fused deposition modeling process. Foreign object damage, localized heating damage, and the resulting delamination between layers were detected in using the technique as indicated by increased amplitude and wavenumber responses within the damaged area.

  10. Contrast enhanced endoscopic ultrasound: More than just a fancy Doppler.

    PubMed

    Mohamed, Rachid M; Yan, Brian M

    2010-07-16

    Contrast enhanced endoscopic ultrasound (CEUS) is a new modality that takes advantage of vascular structure and blood flow to distinguish different clinical entities. Contrast agents are microbubbles that oscillate when exposed to ultrasonographic waves resulting in characteristic acoustic signals that are then converted to colour images. This permits exquisite imaging of macro- and microvasculature, providing information to help delineate malignant from non-malignant processes. The use of CEUS may significantly increase the sensitivity and specificity over conventional endoscopic ultrasound. Currently available contrast agents are safe, with infrequent adverse effects. This review summarizes the theory and technique behind CEUS and the current and future clinical applications.

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

    PubMed

    Zhang, Yu; Zhang, Hong

    2005-10-01

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

  12. 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. PMID:22293750

  13. A method for registration and model-based segmentation of Doppler ultrasound images

    NASA Astrophysics Data System (ADS)

    Kalinić, Hrvoje; Lončarić, Sven; Čikeš, Maja; Milicic, Davor; Čikeš, Ivo; Sutherland, George; Bijnens, Bart

    2009-02-01

    Morphological changes of Doppler ultrasound images are an important source of information for diagnosis of cardiovascular diseases. Quantification of these flow profiles requires segmentation of the ultrasound images. In this article, we propose a new model-based method for segmentation of (aortic outflow) velocity profiles. The method is based on a procedure for registration using a geometric transformation specifically designed for matching Doppler ultrasound profiles. After manual segmentation of a model image, the model image is temporarily registered to a new image using two manually defined points in time. Next, a non-rigid registration was carried out in the velocity direction. As a similarfity measure normalized mutual information is used, while optimization is performed by a genetic algorithm. The registration method is experimentally validated using an in-silico image phantom, and showed an accuracy of 5.4%. The model based on segmentation is evaluated in a seris of aortic outflow Doppler ultrasound images from 30 normal volunteers. Comparing the automated method to the manual delineation by an expert cardiologist the method proved accurate to 6.6%. The experimental results confirm the accuracy of the approach and shows that the method can be used for the segmentation of the clinically obtained aortic outflow velocity profiles.

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

    SciTech Connect

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

    1984-03-01

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

  15. 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.

  16. 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

  17. Duplex Doppler ultrasound study of the temporomandibular joint.

    PubMed

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

    2012-06-01

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

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

    PubMed

    Halls, James; Bydawell, Gareth; Patel, Uday

    2009-11-01

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

  19. 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.

  20. Feature extraction from Doppler ultrasound signals for automated diagnostic systems.

    PubMed

    Ubeyli, Elif Derya; Güler, Inan

    2005-11-01

    This paper presented the assessment of feature extraction methods used in automated diagnosis of arterial diseases. Since classification is more accurate when the pattern is simplified through representation by important features, feature extraction and selection play an important role in classifying systems such as neural networks. Different feature extraction methods were used to obtain feature vectors from ophthalmic and internal carotid arterial Doppler signals. In addition to this, the problem of selecting relevant features among the features available for the purpose of classification of Doppler signals was dealt with. Multilayer perceptron neural networks (MLPNNs) with different inputs (feature vectors) were used for diagnosis of ophthalmic and internal carotid arterial diseases. The assessment of feature extraction methods was performed by taking into consideration of performances of the MLPNNs. The performances of the MLPNNs were evaluated by the convergence rates (number of training epochs) and the total classification accuracies. Finally, some conclusions were drawn concerning the efficiency of discrete wavelet transform as a feature extraction method used for the diagnosis of ophthalmic and internal carotid arterial diseases. PMID:16278106

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

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

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

  2. Doppler ultrasound and tibial tuberosity maturation status predicts pain in adolescent male athletes with Osgood-Schlatter's disease: a case series with comparison group and clinical interpretation

    PubMed Central

    Sailly, Matthieu; Whiteley, Rod; Johnson, Amanda

    2013-01-01

    Background The pathogenesis of the Osgood-Schlatter's disease (OSD) is still debated. The fragmentation of the ossification centre has been questioned as a definitive sign of OSD and has been seen as a normal development of the anterior tibial tubercle (ATT). Objectives It is unknown if such changes are present in the presumed pathological tendon insertion seen in OSD, nor the relation of Doppler-positive changes to pain on clinical examination. Methods A prospective analysis was carried out on 20 consecutive symptomatic male athletes (13.9 years±1.3) and a comparison group of asymptomatic subjects. All underwent a comparative clinical assessment and ultrasound with colour Doppler scan on both knees. Subjective pain was recorded with a visual analogue scale (VAS) during provocative manoeuvres: palpation, resisted contraction and single leg squat. Results Positive Doppler US (within the distal end of the patellar tendon) was associated with higher pain on palpation (47±24.5 vs 18±11.4, p<0.01) and resisted static contraction (59±20.2 vs 27±12.5, p<0.001) compared with Doppler-negative subjects. No Doppler activity was found in the comparison group. VAS for palpation and resisted contraction of the athletes graded as stage 2 (51.1±22.0 and 60.0±21.2) were significantly higher than stage 3 (17.8±12.0 and 18.9±16.9) and stage 4 (15.0±7.1 and 25.0±7.1; p<0.01). Conclusions More painful OSD is associated with the presence of neo-vessels. This may be linked with a particular stage of ATT maturation and applied compressive forces. A Doppler ultrasound scan adds practical information to develop the care plan of the patient. PMID:22952406

  3. 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

  4. A unified approach to modeling the backscattered Doppler ultrasound from blood.

    PubMed

    Mo, L Y; Cobbold, R S

    1992-05-01

    A unified approach to modeling the backscattered Doppler ultrasound signal from blood is presented. The approach consists of summing the contributions from elemental acoustic voxels each containing many red blood cells (RBC's). For an insonified region that is large compared to a wavelength, it is shown that the Doppler signal is a Gaussian random process that arises from fluctuation scattering, which implies that the backscattered power is proportional to the variance of local RBC concentrations. As a result, some common misconceptions about the relationship between the backscattering coefficient and hematocrit can be readily resolved. The unified approach was also used to derive a Doppler signal simulation model which shows that, regardless of flow condition, the power in the Doppler frequency spectrum is governed by the exponential distribution. For finite beamwidth and paraxial flow, it is further shown that the digitized Doppler signal can be modeled by a moving average random process whose order is determined by the signal sampling rate as well as the flow velocity profile.

  5. Colour Doppler ultrasound evaluation of orbital vessels in diabetic retinopathy.

    PubMed

    Baydar, S; Adapinar, B; Kebapci, N; Bal, C; Topbas, S

    2007-06-01

    The aim of this study was to determine the role of colour Doppler imaging in the retrobulbar vascular circulation in diabetic retinopathy (DR). Maximum (V(max)), end-diastolic (V(min)) and average (V(mean)) velocities of blood flows and pulsatility index and resistivity index (RI) in central retinal artery (CRA), short branches of posterior ciliary artery (PCA) and ophthalmic artery of the 65 diabetic and 22 control eyes were measured. The CRA V(max) level in the control group was significantly higher than in DR groups. The CRA V(mean) level was also significantly higher in the control group than in the mild nonproliferative diabetic retinopathy (NPDR) and the moderate NPDR groups. The CRA RI value was significantly higher in the control group than in the nonretinopathy group. The CRA V(min) and the ophthalmic artery RI values were found significantly higher in the nonretinopathy group than in the moderate NPDR group. There were significant decreases in the some CRA and PCA values as glycated haemoglobin (HbA1c) levels increase in diabetic group. There was a positive correlation between the duration of diabetes and HbA1c levels. This study showed the presence of some dynamic circulatory alterations in the nonretinopathy group with diabetes and DR groups. It was also shown that there is a negative correlation between HbA1c and some orbital vascular velocities.

  6. Is transabdominal ultrasound scanning of cervical measurement in mid-trimester pregnancy a useful alternative to transvaginal ultrasound scan?

    PubMed Central

    Chaudhury, Kalyansree; Ghosh, Mrinalkanti; Halder, Atin; Senapati, Sourav; Chaudhury, Sudeshna

    2013-01-01

    Objective The aim of this study is to assess the correlation between transabdominal and transvaginal ultrasound measurements of the cervix in pregnancy. If transabdominal ultrasound measurement of cervical length is found to provide effective information, it could be used in patient counselling and when making clinical decisions. Material and Methods One hundred and twenty seven pregnant patients between 18–26 weeks of pregnancy were enrolled in this prospective study for measuring cervical length, both by transabdominal and transvaginal ultrasound scan after bladder emptying. Transabdominal and transvaginal measurements were compared and correlated. Results In patients with transvaginal ultrasound scan (TVS) cervical length ≤32 mm, TVS cervical length was found to be shorter than by transabdominal ultrasound scan (TAS). Most of these patients needed >3 cm of vertical pocket of urine in the bladder for adequate visualisation of the cervix. In patients with TVS cervical length >32 mm, the TVS measurement of the cervix was longer than the TAS measurement of the cervix. In these patients, the cervix could be seen by TAS when there was either ≤3 cm vertical pocket of urine in the bladder or an empty bladder. Statistical tests showed that there is a significant difference between TAS and TVS cervical measurements and that there is a significant association between these two measurements. Conclusion Most of the patients needed variable degrees of bladder filling for adequate visualisation of the cervix. Although minimal bladder filling does not influence TAS measurements of cervical length, moderate fullness of the bladder does cause an apparent increase in TAS measurements of cervical length. If the cervical length is ≥30 mm by TAS, regardless of urine content in the bladder, the patient can be assured vis a vis their risk of preterm labour as far as cervical length is concerned. However, in patients with TAS cervical measurement <30 mm and where the bladder

  7. 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.

  8. 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.

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

    PubMed Central

    Łasecki, Mateusz; Zaleska-Dorobisz, Urszula

    2015-01-01

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

  10. Assessment of spectral Doppler in preclinical ultrasound using a small-size rotating phantom.

    PubMed

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

    2013-08-01

    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

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

    PubMed

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

    2016-02-01

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

  12. Non-invasive estimation of the mean pressure difference in aortic stenosis by Doppler ultrasound.

    PubMed Central

    Teien, D; Karp, K; Eriksson, P

    1986-01-01

    The mean pressure difference across the valve in aortic stenosis is an indicator of the severity of the obstruction to flow. Non-invasive determination of the mean pressure gradient by Doppler ultrasonography is, however, complicated by the squared relation between instantaneous velocities and pressure differences. The validity of a new simple formula for calculation of the mean pressure difference from the peak pressure difference was evaluated in 26 patients with aortic stenosis. The formula is: delta pmean = 0.64 delta ppeak, where delta pmean is the mean pressure gradient and delta ppeak the peak pressure gradient. There was a close correlation between the mean pressure differences determined by application of the formula to the peak pressure differences measured at catheterisation and the mean pressure differences obtained by planimetry (r = 0.97, SEE = 4.7 mm Hg). The correlation between mean pressure differences determined by continuous wave Doppler ultrasound and the formula and those measured by planimetry was also close (r = 0.91, SEE = 7.6 mm Hg) and only three patients showed a difference between the two methods of greater than 10 mm Hg. The new formula is a simple and reliable means of estimating the mean pressure difference from Doppler recordings and it facilitates the comparison of Doppler and catheterisation data. PMID:3539164

  13. Acoustic Doppler velocity measurement system using capacitive micromachined ultrasound transducer array technology.

    PubMed

    Shin, Minchul; Krause, Joshua S; DeBitetto, Paul; White, Robert D

    2013-08-01

    This paper describes the design, fabrication, modeling, and characterization of a small (1 cm(2) transducer chip) acoustic Doppler velocity measurement system using microelectromechanical systems capacitive micromachined ultrasound transducer (cMUT) array technology. The cMUT sensor has a 185 kHz resonant frequency to achieve a 13° beam width for a 1 cm aperture. A model for the cMUT and the acoustic system which includes electrical, mechanical, and acoustic components is provided. Furthermore, this paper shows characterization of the cMUT sensor with a variety of testing procedures including Laser Doppler Vibrometry (LDV), beampattern measurement, reflection testing, and velocity testing. LDV measurements demonstrate that the membrane displacement at the center point is 0.4 nm/V(2) at 185 kHz. The maximum range of the sensor is 60 cm (30 cm out and 30 cm back). A velocity sled was constructed and used to demonstrate measureable Doppler shifts at velocities from 0.2 to 1.0 m/s. The Doppler shifts agree well with the expected frequency shifts over this range.

  14. Acoustic Doppler velocity measurement system using capacitive micromachined ultrasound transducer array technology.

    PubMed

    Shin, Minchul; Krause, Joshua S; DeBitetto, Paul; White, Robert D

    2013-08-01

    This paper describes the design, fabrication, modeling, and characterization of a small (1 cm(2) transducer chip) acoustic Doppler velocity measurement system using microelectromechanical systems capacitive micromachined ultrasound transducer (cMUT) array technology. The cMUT sensor has a 185 kHz resonant frequency to achieve a 13° beam width for a 1 cm aperture. A model for the cMUT and the acoustic system which includes electrical, mechanical, and acoustic components is provided. Furthermore, this paper shows characterization of the cMUT sensor with a variety of testing procedures including Laser Doppler Vibrometry (LDV), beampattern measurement, reflection testing, and velocity testing. LDV measurements demonstrate that the membrane displacement at the center point is 0.4 nm/V(2) at 185 kHz. The maximum range of the sensor is 60 cm (30 cm out and 30 cm back). A velocity sled was constructed and used to demonstrate measureable Doppler shifts at velocities from 0.2 to 1.0 m/s. The Doppler shifts agree well with the expected frequency shifts over this range. PMID:23927100

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

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

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

  16. 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.

  17. Use of Doppler ultrasound in the management of uteroplacental perfusion during cardiopulmonary bypass in pregnancy.

    PubMed

    Mandel, D C; Pryde, P G; Shah, D M; Iruretagoyena, J I

    2016-08-01

    Cardiopulmonary bypass, the extreme of non-obstetric surgery during pregnancy, presents unique challenges to minimize maternal and fetal risk. We present our experience with a woman who was diagnosed with a left atrial myxoma following an ischemic cerebrovascular accident. We discuss clinical management specific to cardiopulmonary bypass during pregnancy and delivery in the context of a multidisciplinary team approach. We recommend using intermittent Doppler ultrasound as a non-invasive real-time assessment of uteroplacental perfusion during non-obstetric surgery in pregnancy. Monitoring of perfusion facilitates active feedback for appropriate in utero resuscitation in these cases. PMID:27021885

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

    NASA Astrophysics Data System (ADS)

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

    2007-07-01

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

  19. 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

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

    PubMed

    Martin, Eleanor; Shaw, Adam; Lees, Christoph

    2015-08-01

    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.

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

    PubMed Central

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

    2016-01-01

    Background: To evaluate the efficacy of color Doppler ultrasound (CDUS) in differentiating benign and malignant cervical lymph nodes by detecting differences in blood flow patterns. Materials and Methods: In this cross-sectional prospective study, 25 untreated patients with clinical evidence of cervical lymphadenopathy were evaluated. CDUS was performed for 80 cervical lymph nodes. The gray scale parameters of the lymph node and intranodal perfusion sites were the key CDUS features used to differentiate between reactive and metastatic lymph nodes. Histopathological confirmations were obtained and compared with the results of CDUS. Results: Initially, 53 cervical lymph nodes were evaluated by clinical examination. Twenty-seven additional lymph nodes (53 + 27 = 80) were discovered by CDUS evaluation. Gray scale parameters for lymph nodes such as size of lymph node, shape of lymph node, and presence or absence of hilum revealed highly significant results (P < 0.0001). Color Doppler flow signals revealed that central/hilar flow was characteristic for benign nodes whereas peripheral/mixed flow was characteristic for malignant nodes, the findings were highly significant (P < 0.0001). Gray scale and color Doppler features are used to differentiate benign and malignant nodes. Conclusion: Within the limitations of this study, CDUS evaluation was found to be highly significant with a high sensitivity and specificity over clinical evaluation CDUS examination provides a prospect to reduce the need for biopsy/fine needle aspiration cytology in reactive nodes. PMID:27274341

  2. Assessment of Spectral Doppler for an Array-Based Preclinical Ultrasound Scanner Using a Rotating Phantom

    PubMed Central

    Kenwright, David A.; Anderson, Tom; Moran, Carmel M.; Hoskins, Peter R.

    2015-01-01

    Velocity measurement errors were investigated for an array-based preclinical ultrasound scanner (Vevo 2100, FUJIFILM VisualSonics, Toronto, ON, Canada). Using a small-size rotating phantom made from a tissue-mimicking material, errors in pulse-wave Doppler maximum velocity measurements were observed. The extent of these errors was dependent on the Doppler angle, gate length, gate depth, gate horizontal placement and phantom velocity. Errors were observed to be up to 172% at high beam–target angles. It was found that small gate lengths resulted in larger velocity errors than large gate lengths, a phenomenon that has not previously been reported (e.g., for a beam–target angle of 0°, the error was 27.8% with a 0.2-mm gate length and 5.4% with a 0.98-mm gate length). The error in the velocity measurement with sample volume depth changed depending on the operating frequency of the probe. Some edge effects were observed in the horizontal placement of the sample volume, indicating a change in the array aperture size. The error in the velocity measurements increased with increased phantom velocity, from 22% at 2.4 cm/s to 30% at 26.6 cm/s. To minimise the impact of these errors, an angle-dependent correction factor was derived based on a simple ray model of geometric spectral broadening. Use of this angle-dependent correction factor reduces the maximum velocity measurement errors to <25% in all instances, significantly improving the current estimation of maximum velocity from pulse-wave Doppler ultrasound. PMID:25957754

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  4. 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.

  5. Detecting shallow mixing heights in two coastal locations with a scanning Doppler lidar

    NASA Astrophysics Data System (ADS)

    Vakkari, Ville; O'Connor, Ewan J.; Nisantzi, Argyro; Mamouri, Rodanthi E.; Hadjimitsis, Diofantos Gl.

    2015-04-01

    Turbulent mixing is one of the most important processes in the lower troposphere for climate, weather and air quality. A key parameter describing turbulent mixing in atmosphere is mixing height, i.e. the height of the layer that is constantly in contact with the surface. Doppler lidar offers a way to observe the vertical wind velocity profile with a high enough time resolution to retrieve information on turbulent mixing. However, Doppler lidars cannot retrieve wind velocity measurements below an instrument-specific threshold, typically 100 - 200 metres. Here, we introduce a method for identifying mixing heights below the vertical minimum range of a scanning Doppler lidar. The new method for detecting shallow mixing height is based on velocity variance in low elevation angle conical scanning, i.e. vertical azimuth display (VAD) scanning, which provides simultaneously the horizontal wind profile. This method is applied to measurements in two very different coastal environments: Limassol, Cyprus during summer; and Loviisa, Finland during winter. At Limassol the measurements were carried out from 22 August to 15 October 2013 at the Cyprus University of Technology campus, 600 metres NE from the Mediterranean Sea shoreline. At Loviisa, the measurement campaign took place from 10 December 2013 to 17 March 2014 on a 2000 m long, 500 m wide island in the Baltic Sea archipelago. At both locations, the new method agrees well with mixing heights derived from turbulent kinetic energy dissipation rate profiles obtained from vertically-pointing Doppler lidar measurements. Furthermore, when the vertically pointing measurements indicated the mixing height to be below the Doppler lidar minimum range, the VADs indicated a shallow mixing height on 87 % of the time at Loviisa and on 58 % of the time at Limassol. At Limassol such low mixing heights occurred only during the night; at Loviisa very low mixing heights were also common during the day.

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

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

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

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

    PubMed

    Hata, Toshiyuki; Tanaka, Hirokazu; Noguchi, Junko

    2012-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    1998-06-01

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

  9. 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.

  10. 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. PMID:25583044

  11. Ultrasound Color Doppler Image Segmentation and Feature Extraction in MCP and Wrist Region in Evaluation of Rheumatoid Arthritis.

    PubMed

    Snekhalatha, U; Muthubhairavi, V; Anburajan, M; Gupta, Neelkanth

    2016-09-01

    The present study focuses on automatically to segment the blood flow pattern of color Doppler ultrasound in hand region of rheumatoid arthritis patients and to correlate the extracted the statistical features and color Doppler parameters with standard parameters. Thirty patients with rheumatoid arthritis (RA) and their total of 300 joints of both the hands, i.e., 240 MCP and 60 wrists were examined in this study. Ultrasound color Doppler of both the hands of all the patients was obtained. Automated segmentation of color Doppler image was performed using color enhancement scaling based segmentation algorithm. The region of interest is fixed in the MCP joints and wrist of the hand. Features were extracted from the defined ROI of the segmented output image. The color fraction was measured using Mimics software. The standard parameters such as HAQ score, DAS 28 score, and ESR was obtained for all the patients. The color fraction tends to be increased in wrist and MCP3 joints which indicate the increased blood flow pattern and color Doppler activity as part of inflammation in hand joints of RA. The ESR correlated significantly with the feature extracted parameters such as mean, standard deviation and entropy in MCP3, MCP4 joint and the wrist region. The developed automated color image segmentation algorithm provides a quantitative analysis for diagnosis and assessment of RA. The correlation study between the color Doppler parameters with the standard parameters provides moral significance in quantitative analysis of RA in MCP3 joint and the wrist region.

  12. [Ultrasound artifacts and their diagnostic significance in internal medicine and gastroenterology - part 2: color and spectral Doppler artifacts].

    PubMed

    Jenssen, C; Tuma, J; Möller, K; Cui, X W; Kinkel, H; Uebel, S; Dietrich, C F

    2016-06-01

    Artifacts in ultrasonographic diagnostics are a result of the physical properties of the ultrasound waves and are caused by interaction of the ultrasound waves with biological structures and tissues of the body and with foreign materials. On the one hand, they may be diagnostically helpful. On the other hand, they may be distracting and may lead to misdiagnosis. Profound knowledge of the causes, avoidance, and interpretation of artifacts is a necessary precondition for correct clinical appraisal of ultrasound images. Part 1 of this review commented on the physics of artifacts and described the most important B-mode artifacts. Part 2 focuses on the clinically relevant artifacts in Doppler and color-coded duplex sonography. Problems and pitfalls of interpretation arising from artifacts, as well as the diagnostic use of Doppler and colour-coded duplex sonography, are discussed.

  13. [Ultrasound artifacts and their diagnostic significance in internal medicine and gastroenterology - part 2: color and spectral Doppler artifacts].

    PubMed

    Jenssen, C; Tuma, J; Möller, K; Cui, X W; Kinkel, H; Uebel, S; Dietrich, C F

    2016-06-01

    Artifacts in ultrasonographic diagnostics are a result of the physical properties of the ultrasound waves and are caused by interaction of the ultrasound waves with biological structures and tissues of the body and with foreign materials. On the one hand, they may be diagnostically helpful. On the other hand, they may be distracting and may lead to misdiagnosis. Profound knowledge of the causes, avoidance, and interpretation of artifacts is a necessary precondition for correct clinical appraisal of ultrasound images. Part 1 of this review commented on the physics of artifacts and described the most important B-mode artifacts. Part 2 focuses on the clinically relevant artifacts in Doppler and color-coded duplex sonography. Problems and pitfalls of interpretation arising from artifacts, as well as the diagnostic use of Doppler and colour-coded duplex sonography, are discussed. PMID:27284933

  14. 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 ...

  15. 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.

  16. 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.

  17. 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

  18. Transcranial Doppler Ultrasound: A Review of the Physical Principles and Major Applications in Critical Care

    PubMed Central

    Ahmad, Gulraiz

    2013-01-01

    Transcranial Doppler (TCD) is a noninvasive ultrasound (US) study used to measure cerebral blood flow velocity (CBF-V) in the major intracranial arteries. It involves use of low-frequency (≤2 MHz) US waves to insonate the basal cerebral arteries through relatively thin bone windows. TCD allows dynamic monitoring of CBF-V and vessel pulsatility, with a high temporal resolution. It is relatively inexpensive, repeatable, and portable. However, the performance of TCD is highly operator dependent and can be difficult, with approximately 10–20% of patients having inadequate transtemporal acoustic windows. Current applications of TCD include vasospasm in sickle cell disease, subarachnoid haemorrhage (SAH), and intra- and extracranial arterial stenosis and occlusion. TCD is also used in brain stem death, head injury, raised intracranial pressure (ICP), intraoperative monitoring, cerebral microembolism, and autoregulatory testing. PMID:24455270

  19. Displacement vector measurement using instantaneous ultrasound signal phase - multidimensional autocorrelation and doppler methods.

    PubMed

    Sumi, Chikayoshi

    2008-01-01

    Two new methods of measuring a multidimensional displacement vector using an instantaneous ultrasound signal phase are described, i.e., the multidimensional autocorrelation method (MAM) and multidimensional Doppler method (MDM). A high measurement accuracy is achieved by combining either method with the lateral Gaussian envelope cosine modulation method (LGECMM) or multidirectional synthetic aperture method (MDSAM). Measurement accuracy is evaluated using simulated noisy echo data. Both methods yield accurate measurements comparable to that of our previously developed cross-spectrum phase gradient method (MCSPGM); however, they require less computational time (the order, MDM < MAM approximate, equals MCSPGM) and would provide realtime measurements. Moreover, comparisons of LGECMM and MDSAM performed by geometrical evaluations clarifies that LGECMM has potentials to yield more accurate measurements with less computational time. Both MAM and MDM can be applied to the measurement of tissue strain, blood flow, sonar data, and other target motions.

  20. Surface wave measurements using a single continuously scanning laser Doppler vibrometer: application to elastography.

    PubMed

    Salman, Muhammad; Sabra, Karim G

    2013-03-01

    A continuous scanning laser Doppler vibrometry (CSLDV) obtained sweeping a single laser beam along a periodic scan pattern allows measuring surface vibrations at many points simultaneously by demultiplexing the CSLDV signal. This known method fundamentally differs from conventional scanning laser vibrometry techniques in which the laser beam is kept at a fixed point during each measurement and then moved to a new position prior to the next measurement. This article demonstrates the use of a CSLDV for measuring in a non-contact fashion the velocity of low-frequency surface waves (f < 100 Hz) propagating over soft materials, namely here gel surfaces-mimicking human body soft tissues-and skeletal muscles, to develop an affordable and noninvasive elastography modality. The CSLDV vibration measurements obtained with a single laser beam, linearly scanned over the test surface at 200 Hz over lengths up to 6 cm, were validated using an array of three fixed laser Doppler vibrometers distributed along the same scan line. Furthermore, this CSLDV setup was used to measure the increase in surface wave velocity over the biceps brachii muscle which was directly correlated to the actual stiffening of the biceps occurring while a subject was performing voluntary contractions at an increasing level.

  1. Surface wave measurements using a single continuously scanning laser Doppler vibrometer: application to elastography.

    PubMed

    Salman, Muhammad; Sabra, Karim G

    2013-03-01

    A continuous scanning laser Doppler vibrometry (CSLDV) obtained sweeping a single laser beam along a periodic scan pattern allows measuring surface vibrations at many points simultaneously by demultiplexing the CSLDV signal. This known method fundamentally differs from conventional scanning laser vibrometry techniques in which the laser beam is kept at a fixed point during each measurement and then moved to a new position prior to the next measurement. This article demonstrates the use of a CSLDV for measuring in a non-contact fashion the velocity of low-frequency surface waves (f < 100 Hz) propagating over soft materials, namely here gel surfaces-mimicking human body soft tissues-and skeletal muscles, to develop an affordable and noninvasive elastography modality. The CSLDV vibration measurements obtained with a single laser beam, linearly scanned over the test surface at 200 Hz over lengths up to 6 cm, were validated using an array of three fixed laser Doppler vibrometers distributed along the same scan line. Furthermore, this CSLDV setup was used to measure the increase in surface wave velocity over the biceps brachii muscle which was directly correlated to the actual stiffening of the biceps occurring while a subject was performing voluntary contractions at an increasing level. PMID:23463997

  2. Current Applications of Scanning Coherent Doppler Lidar in Wind Energy Industry

    NASA Astrophysics Data System (ADS)

    Krishnamurthy, R.; Boquet, M.; Osler, E.

    2016-06-01

    Scanning Doppler Lidars have become more prominent in the wind energy industry for a variety of applications. Scanning Lidar's provide spatial variation of winds and direction over a large area, which can be used to assess the spatial uncertainty of winds and analyze complex flows. Due to the recent growth in wind energy, wind farms are being built in complex terrain areas and fine tuning of the existing wind farms for optimized performance have gained significant interest. Scanning Lidar is an ideal tool for improved assessment of flow over complex terrains and wake characterization of large wind farms. In this article, the various applications of Lidar in the wind industry are discussed and results from several campaigns conducted in US and Europe is presented. The conglomeration of results provided in this article would assist wind energy developers and researchers in making improved decisions about their wind farm operations and pre-construction analysis using scanning Lidar's.

  3. A feasibility study for measuring accurate tendon displacements using an audio-based Fourier analysis of pulsed-wave Doppler ultrasound signals.

    PubMed

    Stegman, K J; Podhorodeski, R P; Park, E J

    2009-01-01

    The accuracy of Pulsed-Wave Doppler Ultrasound displacement measurements of a slow moving "tendon-like" string was investigated in this study. This was accomplished by estimating string displacements using an audio-based Fourier analysis of a Pulsed-Wave Doppler signal from a commercial ultrasound scanner. Our feasibility study showed that the proposed technique is much more accurate at estimating the actual string displacement in comparison to the scanner's onboard software. Furthermore, this study also shows that a real-time Doppler data acquisition from an ultrasound scanner is possible for the ultimate purpose of real-time biological tendon displacement monitoring.

  4. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

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

    PubMed Central

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

    2013-01-01

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

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

    PubMed

    Hashmi, Faiz R; Elfandi, Khaled O

    2016-06-27

    Osteoporosis is the most common metabolic disease with significant impact on the morbidity and mortality of affected patients. Osteoporosis has a significant impact on the economy worldwide. The aim of this study was to find out whether heel ultrasound is as good as central bone densitometry scanning in diagnosing osteoporosis in patients who are at high risk of osteoporosis. This was a prospective study of patients comparing heel ultrasound to central bone densitometry scanning (dual X-ray absorptiometry, DEXA) in patients. The recruited patients attended for a DEXA scan of the left hip and lumbar spine. All subjects had an ultrasound of the left heel using the quantitative heel ultrasound machine. The results of DEXA scan were blinded from the results of ultrasound and vice versa. There were 59 patients who took part in the study, 12 men and 47 women. The mean age was 66 years (SD 11.9) and mean weight was 62.5 kg (SD 10.7). The sensitivity and specificity of the ultrasound heel test to predict osteoporosis were 53% (95%CI: 29-77) and 86% (95%CI: 75-96) respectively. Specificity for predicting bone mineral density (BMD)-defined osteoporosis was high (86%), but sensitivity was low (53%). A heel ultrasound result in the osteoporotic range was highly predictive of BMD-defined osteoporosis. A positive ultrasound heel test in high risk patients is more useful in ruling in osteoporosis than a negative test to rule out osteoporosis. PMID:27433300

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

    PubMed Central

    Hashmi, Faiz R.; Elfandi, Khaled O.

    2016-01-01

    Osteoporosis is the most common metabolic disease with significant impact on the morbidity and mortality of affected patients. Osteoporosis has a significant impact on the economy worldwide. The aim of this study was to find out whether heel ultrasound is as good as central bone densitometry scanning in diagnosing osteoporosis in patients who are at high risk of osteoporosis. This was a prospective study of patients comparing heel ultrasound to central bone densitometry scanning (dual X-ray absorptiometry, DEXA) in patients. The recruited patients attended for a DEXA scan of the left hip and lumbar spine. All subjects had an ultrasound of the left heel using the quantitative heel ultrasound machine. The results of DEXA scan were blinded from the results of ultrasound and vice versa. There were 59 patients who took part in the study, 12 men and 47 women. The mean age was 66 years (SD 11.9) and mean weight was 62.5 kg (SD 10.7). The sensitivity and specificity of the ultrasound heel test to predict osteoporosis were 53% (95%CI: 29-77) and 86% (95%CI: 75-96) respectively. Specificity for predicting bone mineral density (BMD)-defined osteoporosis was high (86%), but sensitivity was low (53%). A heel ultrasound result in the osteoporotic range was highly predictive of BMD-defined osteoporosis. A positive ultrasound heel test in high risk patients is more useful in ruling in osteoporosis than a negative test to rule out osteoporosis. PMID:27433300

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

    PubMed

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

    2010-01-01

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

  11. Accurate flexural spring constant calibration of colloid probe cantilevers using scanning laser Doppler vibrometry.

    PubMed

    Gates, Richard S; Osborn, William A; Shaw, Gordon A

    2015-06-12

    Calibration of the flexural spring constant for atomic force microscope (AFM) colloid probe cantilevers provides significant challenges. The presence of a large attached spherical added mass complicates many of the more common calibration techniques such as reference cantilever, Sader, and added mass. Even the most promising option, AFM thermal calibration, can encounter difficulties during the optical lever sensitivity measurement due to strong adhesion and friction between the sphere and a surface. This may cause buckling of the end of the cantilever and hysteresis in the approach-retract curves resulting in increased uncertainty in the calibration. Most recently, a laser Doppler vibrometry thermal method has been used to accurately calibrate the normal spring constant of a wide variety of tipped and tipless commercial cantilevers. This paper describes a variant of the technique, scanning laser Doppler vibrometry, optimized for colloid probe cantilevers and capable of spring constant calibration uncertainties near ±1%.

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

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

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

  13. Continuous scanning laser Doppler vibrometry and wavelet processing for diagnostics: A time domain approach

    NASA Astrophysics Data System (ADS)

    Chiariotti, P.; Revel, G. M.; Martarelli, M.

    2016-06-01

    Continuous Scanning Laser Doppler Vibrometry (CSLDV) is a well-known technique within the structural dynamic community. However, the whole potentials of CSLDV for diagnostic purposes have not been fully exploited yet. This paper presents a time domain approach for identifying damages in structures. The method, which is based on a wavelet processing of vibration data collected by CSLDV, does not need any a-priori knowledge of the vibration behavior of the undamaged sample. Applications on real test cases are presented and discussed in the paper, demonstrating the promising performance of the approach as a non-destructive testing technique.

  14. 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

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

    NASA Astrophysics Data System (ADS)

    Weekes, Ben; Ewins, David

    2015-06-01

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

  16. 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

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

    PubMed

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

    2016-01-01

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

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

    PubMed Central

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

    2016-01-01

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

  19. 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

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

    PubMed

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

    2015-10-01

    To compare the capability of ultrasound strain and Doppler parameters in the assessment of renal allograft interstitial fibrosis/tubular atrophy (IF/TA), we prospectively measured ultrasound corticomedullary strain (strain) and intra-renal artery Doppler end-diastolic velocity (EDV), peak systolic velocity (PSV) and resistive index (RI) in 45 renal transplant recipients before their kidney biopsies. We used 2-D speckle tracking to estimate strain, the deformation ratio of renal cortex to medulla produced by external compression using the ultrasound transducer. We also measured Doppler EDV, PSV and RI at the renal allograft inter-lobar artery. Using the Banff scoring system for renal allograft IF/TA, 45 patients were divided into the following groups: group 1 with ≤5% (n = 12) cortical IF/TA; group 2 with 6%-25% (n = 12); group 3 with 26%-50% (n = 11); and group 4 with >50% (n = 10). We performed receiver operating characteristic curve analysis to test the accuracy of these ultrasound parameters and duration of transplantation in determining >26% cortical IF/TA. In our results, strain was statistically significant in all paired groups (all p < 0.005) and inversely correlated with the grade of cortical IF/TA (p < 0.001). However, the difference in PSV and EDV was significant only between high-grade (>26%, including 26%-50% and >50%) and low-grade (≤25%, including <5% and 6%-25%) cortical IF/TA (p < 0.001). RI did not significantly differ in any paired group (all p > 0.05). The areas under the receiver operating characteristic curve for strain, EDV, PSV, RI and duration of transplantation in determining >26% cortical IF/TA were 0.99, 0.94, 0.88, 0.52 and 0.92, respectively. Our results suggest that corticomedullary strain seems to be superior to Doppler parameters and duration of transplantation in assessment of renal allograft cortical IF/TA.

  1. 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

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

    PubMed

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

    2013-07-23

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

  3. When is contrast-enhanced sonography preferable over conventional ultrasound combined with Doppler imaging in renal transplantation?

    PubMed Central

    Zeisbrich, Markus; Kihm, Lars P.; Drüschler, Felix; Zeier, Martin; Schwenger, Vedat

    2015-01-01

    Conventional ultrasound in combination with colour Doppler imaging is still the standard diagnostic procedure for patients after renal transplantation. However, while conventional ultrasound in combination with Doppler imaging can diagnose renal artery stenosis and vein thrombosis, it is not possible to display subtle microvascular tissue perfusion, which is crucial for the evaluation of acute and chronic allograft dysfunctions. In contrast, real-time contrast-enhanced sonography (CES) uses gas-filled microbubbles not only to visualize but also to quantify renal blood flow and perfusion even in the small renal arterioles and capillaries. It is an easy to perform and non-invasive imaging technique that augments diagnostic capabilities in patients after renal transplantation. Specifically in the postoperative setting, CES has been shown to be superior to conventional ultrasound in combination with Doppler imaging in uncovering even subtle microvascular disturbances in the allograft perfusion. In addition, quantitative perfusion parameters derived from CES show predictive capability regarding long-term kidney function. PMID:26413289

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

    PubMed Central

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

    2014-01-01

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

  5. 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.

  6. Scanning Laser Doppler Vibrometry Application to Artworks: New Acoustic and Mechanical Exciters for Structural Diagnostics

    NASA Astrophysics Data System (ADS)

    Agnani, A.; Esposito, E.

    After first attempts some years ago, the scanning laser Doppler vibrometer has become an effective way of diagnosing different types of artworks; successful applications regard frescoes, icons, mosaics, ceramic artefacts and wood inlays. Also application to historical bridges has been successfully developed and a recently approved European Commission project will see the employment of scanning laser Doppler Vibrometry (SLDV) for the dynamical characterization of ancient buildings. However, a critical issue consists in the adequate excitation of the structure under test. Moreover different types of defects and different kinds of artworks require different types of excitation, so this topic needs a deep consideration. In this work we will present two new types of exciters developed at our Department, namely an acoustic exciter and a mechanical one. Acoustic exciters allow remote non-invasive loading but are limited in the lower frequency range and in the amount of vibrational energy input into the structure. The proposed automatic tapping device based on a commercial impact hammer overcomes these problems. Also another acoustic exciter, a HyperSonic Sound (HSS) source has been evaluated, showing interesting features as regards sound radiation.

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

    PubMed

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

    2015-01-01

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

  8. An online three-class Transcranial Doppler ultrasound brain computer interface.

    PubMed

    Goyal, Anuja; Samadani, Ali-Akbar; Guerguerian, Anne-Marie; Chau, Tom

    2016-06-01

    Brain computer interfaces (BCI) can provide communication opportunities for individuals with severe motor disabilities. Transcranial Doppler ultrasound (TCD) measures cerebral blood flow velocities and can be used to develop a BCI. A previously implemented TCD BCI system used verbal and spatial tasks as control signals; however, the spatial task involved a visual cue that awkwardly diverted the user's attention away from the communication interface. Therefore, vision-independent right-lateralized tasks were investigated. Using a bilateral TCD BCI, ten participants controlled online, an on-screen keyboard using a left-lateralized task (verbal fluency), a right-lateralized task (fist motor imagery or 3D-shape tracing), and unconstrained rest. 3D-shape tracing was generally more discernible from other tasks than was fist motor imagery. Verbal fluency, 3D-shape tracing and unconstrained rest were distinguished from each other using a linear discriminant classifier, achieving a mean agreement of κ=0.43±0.17. These rates are comparable to the best offline three-class TCD BCI accuracies reported thus far. The online communication system achieved a mean information transfer rate (ITR) of 1.08±0.69bits/min with values reaching up to 2.46bits/min, thereby exceeding the ITR of previous online TCD BCIs. These findings demonstrate the potential of a three-class online TCD BCI that does not require visual task cues.

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

    PubMed Central

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

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    1997-05-01

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

  11. An online three-class Transcranial Doppler ultrasound brain computer interface.

    PubMed

    Goyal, Anuja; Samadani, Ali-Akbar; Guerguerian, Anne-Marie; Chau, Tom

    2016-06-01

    Brain computer interfaces (BCI) can provide communication opportunities for individuals with severe motor disabilities. Transcranial Doppler ultrasound (TCD) measures cerebral blood flow velocities and can be used to develop a BCI. A previously implemented TCD BCI system used verbal and spatial tasks as control signals; however, the spatial task involved a visual cue that awkwardly diverted the user's attention away from the communication interface. Therefore, vision-independent right-lateralized tasks were investigated. Using a bilateral TCD BCI, ten participants controlled online, an on-screen keyboard using a left-lateralized task (verbal fluency), a right-lateralized task (fist motor imagery or 3D-shape tracing), and unconstrained rest. 3D-shape tracing was generally more discernible from other tasks than was fist motor imagery. Verbal fluency, 3D-shape tracing and unconstrained rest were distinguished from each other using a linear discriminant classifier, achieving a mean agreement of κ=0.43±0.17. These rates are comparable to the best offline three-class TCD BCI accuracies reported thus far. The online communication system achieved a mean information transfer rate (ITR) of 1.08±0.69bits/min with values reaching up to 2.46bits/min, thereby exceeding the ITR of previous online TCD BCIs. These findings demonstrate the potential of a three-class online TCD BCI that does not require visual task cues. PMID:26795195

  12. 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.

  13. Role of ultrasound and color doppler in diagnosis of periapical lesions of endodontic origin at varying bone thickness

    PubMed Central

    Tikku, Aseem P; Bharti, Ramesh; Sharma, Neha; Chandra, Anil; Kumar, Ashutosh; Kumar, Sunil

    2016-01-01

    Aims: To access the role of ultrasound and color doppler in diagnosing periapical lesions of maxilla and mandible. Settings and Design: This study was conducted in the Department of Conservative Dentistry and Endodontics (Faculty of Dental Sciences), Department of Radiotherapy, and Department of Pathology. Materials and Methods: The study group comprised 30 patients with periapical lesions of endodontic origin in maxilla and mandible requiring endodontic surgery. After thorough clinical and radiographic examination patients were subjected to ultrasound and color doppler examination, where the lesions were assessed for their contents as to cystic or solid. Following which periapical surgery was done and the pathological tissue obtained was subjected to histopathological examination. The results of the ultrasound examination were correlated with histopathological features. The diagnostic validity of ultrasound was assessed by calculating the sensitivity, specificity, positive predictive value, and negative predictive value. Statistical Analysis Used: The statistical analysis was done using statistical package for social sciences (SPSS) version 15.0 statistical analysis software. The values were represented in number (%). Results: Within the limitations of the current study it can be stated that although ultrasound may not establish the definitive diagnosis, it can facilitate the differential diagnosis between cystic and solid granulomatous lesions. However, this technique may have a limited role in detecting periapical lesions present in the region with thick overlying cortical bone. Conclusion: Ultrasound can routinely be recommended as a complimentary method for the diagnosis of periapical lesions of endodontic origin. However, this technique may have a limited role in detecting periapical lesions present in the region with thick overlying cortical bone. PMID:27099421

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

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

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

  15. 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. PMID:24110822

  16. 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

  17. 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.

  18. Broadband measurement of translational and angular vibrations using a single continuously scanning laser Doppler vibrometer.

    PubMed

    Salman, Muhammad; Sabra, Karim G

    2012-09-01

    A continuous scanning laser Doppler velocimetry (CSLDV) technique is used to measure the low frequency broadband vibrations associated with human skeletal muscle vibrations (typically f < 100 Hz) by continuously varying the orientation of laser beam over distances that are short compared to the characteristic wavelengths of the vibrations. The high frequency scan (compared to the vibration frequency) enables the detection of broadband translational and angular velocities at a single point using amplitude demodulation of the CSDLV signal. For instance, linear scans allow measurement of the normal surface velocity and one component of angular velocity vector, while circular scans allow measurement of an additional angular velocity component. This CSLDV technique is first validated here using gel samples mimicking soft tissues and then applied to measure multiple degrees of freedom (DOF) of a subject's hand exhibiting fatigue-induced tremor. Hence this CSLDV technique potentially provides a means for measuring multiple DOF of small human body parts (e.g., fingers, tendons, small muscles) for various applications (e.g., haptic technology, remote surgery) when the use of skin-mounted sensors (e.g. accelerometers) can be problematic due to mass-loading artifacts or tethering issues.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

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

    NASA Astrophysics Data System (ADS)

    Montopoli, Mario

    2016-07-01

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

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

    PubMed

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

    2010-09-27

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

  2. The use of twinkling artifact of Doppler imaging to monitor cavitation in tissue during high intensity focused ultrasound therapy

    PubMed Central

    Khokhlova, Tatiana; Li, Tong; Sapozhnikov, Oleg; Hwang, Joo Ha

    2015-01-01

    In high intensity focused ultrasound (HIFU) therapy, it is important to monitor the presence and activity of microbubbles in tissue during treatment. The current methods, - passive cavitation detection (PCD) and B-mode imaging - have limited sensitivity, especially to small-size, non-violently-collapsing microbubbles. Here, a new method for microbubble detection is proposed, based on “twinkling” artifact (TA) of Doppler imaging. TA occurs when Color Doppler ultrasound is used to image hard objects in tissue (e.g., kidney stones), and is displayed as brightly colored spots. As demonstrated recently, TA can be explained by irregular scattering of the Doppler ensemble pulses from the fluctuating microbubbles trapped in crevices of the kidney stone. In this work, TA was used to detect cavitation in tissue and in polyacrylamide gel phantoms during pulsed 1 MHz HIFU exposures with different peak negative pressures (1.5–11 MPa). At each pressure level, the probability of cavitation occurrence was characterized using TA and the broadband signals recorded by PCD, aligned confocally with the HIFU transducer. The results indicate that TA is more sensitive to the onset of cavitation than conventional PCD detection, and allows for accurate spatial localization of the bubbles. Work supported by RFBR and NIH (EB007643, 1K01EB015745, R01CA154451). PMID:26185591

  3. [Transcranial Doppler ultrasound in craniocerebral trauma: valuable method in traumatologic emergency cases?].

    PubMed

    Burger, R; Hassler, W

    1993-02-01

    Introduction of the transcranial Doppler method 1982 (1) by Aaslid made it possible for the first time to monitor noninvasively the cerebral haemodynamics after severe head injury, or in polytraumatized patients in the emergency room. Mean flow velocities (FVmean) and systolic-diastolic frequency spectrum (PI) in basal cerebral arteries were considered. In that way, influences of different pathological intracerebral processes to cerebral haemodynamics are detectable earlier and triage planning of therapeutic steps is facilitated. The following haemodynamic changes are detectable: Increased intracranial vascular flow resistance due to raised intracranial pressure after SHI, hyperaemia due to short-term hypoxia or SHI, decreased intracerebral perfusion after ischaemia or beginning cerebral circulatory arrest, and increased flow velocities (FV) in case of traumatic A.V. fistulas or traumatic vasospasm. Primary experiences in patients with raised intracranial pressure were collected by Hassler, who found a correlation between characteristic Doppler flow signals in case of increasing intracranial pressure and circulatory arrest (Abb. 1). In case of space-occupying epidural, subdural or intracerebral bleedings or brain swelling, the average FV decreases and the pulsatility index increases as a sign of high flow resistance. In beginning of circulatory arrest, oscillating flow or systolic spikes are detectable. After resuscitation early posthypoxic flow acceleration is also visible immediately after admission to the emergency room. In case of ischaemia with detection of hypo-densities in CCT scan, flow velocities are decreased. Traumatic A.V fistulas, especially the carotid sinus cavernous fistula (CCSF), and the haemodynamic consequences to the circle of Willis are seen, a high mean flow velocity with increased end-diastolic flow at fistula sight being noticeable.2+ in the emergency room. If this is not possible, interpretation of flow signals and measured flow velocities

  4. Conformal scanning laser Doppler vibrometer measurement of tenor steelpan response to impulse excitation.

    PubMed

    Ryan, Teresa; O'Malley, Patrick; Glean, Aldo; Vignola, Joseph; Judge, John

    2012-11-01

    A conformal scanning laser Doppler vibrometer system is used in conjunction with a mechanical pannist to measure the surface normal vibration of the entire playing surface of a C-lead tenor steelpan. The mechanical pannist is a device designed to deliver controlled, repeatable strikes that mimic a mallet during authentic use. A description of the measurement system is followed by select examples of behavior common to the results from three different excitation notes. A summary of observed response shapes and associated frequencies demonstrates the concerted placement of note overtones by the craftsmen who manufacture and tune the instruments. The measurements provide a rich mechanical snapshot of the complex motion that generates the distinctive sound of a steelpan.

  5. Utilization of antenatal ultrasound scan and implications for caesarean section: a cross-sectional study in rural Eastern China

    PubMed Central

    2012-01-01

    Background Antenatal ultrasound scan is a widely accepted component of antenatal care. Studies have looked at the relationship between ultrasound scanning and caesarean section (CS) in certain groups of women in China. However, there are limited data on the utilization of antenatal ultrasound scanning in the general population, including its association with CS. The purpose of this study is to describe the utilization of antenatal ultrasound screening in rural Eastern China and to explore the association between antenatal ultrasound scan and uptake of CS. Methods Based on a cluster randomized sample, a total of 2326 women with childbirth participated in the study. A household survey was conducted to collect socio-economic information, obstetric history and utilization of maternal health services. Results Coverage of antenatal care was 96.8% (2251/2326). During antenatal care, 96.1% (2164/2251) women received ultrasound screening and the reported average number was 2.55. 46.8% women received at least 3 ultrasound scans and the maximum number reached 11. The CS rate was found to be 54.8% (1275/2326). After adjusting for socio-demographic and clinical variables, it showed a statistically significant association between antenatal ultrasound scans and uptake of CS by multivariate logistic regression model. High husband education level, high maternal age, having previous adverse pregnant outcome and pregnancy complications during the index pregnancy were also found to be risk factors of choosing a CS. Conclusions A high use of antenatal ultrasound scan in rural Eastern China is found and is influenced by socio-demographic and clinical factors. Evidence-based guidelines for antenatal ultrasound scans need to be developed and disseminated to clinicians including physicians, nurses and sonographers. Guidance about the appropriate use of ultrasound scans should also be shared with women in order to discourage unreasonable expectations and demands. It is important to monitor

  6. [Ultrasound scanning of abdominal contusions in children: experience at the Yopougon CHU (Ivory Coast)].

    PubMed

    N'Goan, A M; Aguehounde, C; N'Gbesso, R D; Moh, N; Roux, C; Keita, K

    1997-01-01

    Ultrasound scans were used to study 23 cases of abdominal contusion in children, between January 1992 and December 1993. Thirteen boys and 10 girls were studied. They were all aged between 4 and 14 years, with a mean age of 6 years. The main causes of their injuries were road accidents (12 cases) and play (11 cases). Ultrasound scans were normal in 6 patients and pathological in 17 patients. The most frequently observed injuries were visceral effects (12 cases), almost always associated with hemoperitoneum. In three cases, hemoperitoneum was detected in the absence of visceral effects. The spleen (4 cases) and the liver (4 cases) were the most frequently injured organs. The other injuries detected included renal hematoma, bladder rupture and parietal hematoma. Diagnosis on the basis of ultrasound scans was found to be incorrect in three cases where diagnosis was repeated after the scan. One case involved a blocked perforation of the rectum, one a benign cyst and the other a mesenteric cyst. Despite these misdiagnoses, ultrasound scanning is a highly sensitive and specific method for examination of contusions in children. It is very useful and often sufficient for accurate diagnosis, particularly in units with only modest technical support. PMID:9480035

  7. The usefulness of ultrasound colour-Doppler twinkling artefact for detecting urolithiasis compared with low dose nonenhanced computerized tomography.

    PubMed

    Winkel, Rikke Rass; Kalhauge, Anna; Fredfeldt, Knud-Erik

    2012-07-01

    This prospective study evaluates the usefulness of the twinkling artefact (TA) seen on colour-Doppler ultrasound (US) in diagnosing urolithiasis. US and standard computed tomography (CT) were performed blinded on 105 patients. B-mode US and colour-Doppler used separately and in combination showed 55% sensitivity and 99% specificity (positive predictive value [PPV] 67% and negative predictive value [NPV] 98%). Of CT verified stones, 61% were ≤3 mm. TAs were present in 74% of the B-mode stones (43% of all CT verified stones). Patients with CT verified stone disease had significantly more TAs in other foci than the stone(s) found on CT, suggestive of microlithiasis. In conclusion, colour-Doppler TA is a helpful supplement for detecting urolithiasis when CT is contraindicated. In addition, US can be valuable in monitoring stones left to pass without intervention if they have presented a TA. CT, US and US with colour-Doppler TA can be useful as complementary techniques for detecting stones.

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

    NASA Astrophysics Data System (ADS)

    Wang, Qi; Xu, Diyun; Liu, Jianguo

    2009-10-01

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

  9. Measurement of coronary flow using high-frequency intravascular ultrasound imaging and pulsed Doppler velocimetry: in vitro feasibility studies.

    PubMed

    Grayburn, P A; Willard, J E; Haagen, D R; Brickner, M E; Alvarez, L G; Eichhorn, E J

    1992-01-01

    The recent development of intravascular ultrasound imaging offers the potential to measure blood flow as the product of vessel cross-sectional area and mean velocity derived from pulsed Doppler velocimetry. To determine the feasibility of this approach for measuring coronary artery flow, we constructed a flow model of the coronary circulation that allowed flow to be varied by adjusting downstream resistance and aortic driving pressure. Assessment of intracoronary flow velocity was accomplished using a commercially available end-mounted pulsed Doppler catheter. Cross-sectional area of the coronary artery was measured using a 20 MHz mechanical imaging transducer mounted on a 4.8 F catheter. The product of mean velocity and cross-sectional area was compared with coronary flow measured by timed collection in a graduated cylinder by linear regression analysis. Excellent correlations were obtained between coronary flow calculated by the ultrasound method and measured coronary flow at both ostial (r = 0.99, standard error of the estimate [SEE] = 13.9 ml/min) and distal (r = 0.98, SEE = 23.0 ml/min) vessel locations under steady flow conditions. During pulsatile flow, calculated and measured coronary flow also correlated well for ostial (r = 0.98, SEE = 12.7 ml/min) and downstream (r = 0.99, SEE = 9.3 ml/min) locations. That the SEE was lower for pulsatile as compared with steady flow may be explained by the blunting of the flow profile across the vessel lumen by the acceleration phase of pulsatile flow. These data establish the feasibility of measuring coronary artery blood flow using intravascular ultrasound imaging and pulsed Doppler techniques. PMID:1531416

  10. Variable pump flow-based Doppler ultrasound method: a novel approach to the measurement of access flow in hemodialysis patients.

    PubMed

    Lin, Chih-Ching; Chang, Chao-Fu; Chiou, Hong-Jen; Sun, Ying-Chou; Chiang, Shou-Shan; Lin, Ming-Wei; Lee, Pui-Ching; Yang, Wu-Chang

    2005-01-01

    Decreasing vascular access flow (Qa) is an important predictor of future access thrombosis and malfunction for hemodialysis (HD) patients. Among all of the methods for determining Qa, the variable pump flow (VPF) Doppler method measures Qa according to the change in Doppler signal between the arterial and the venous needles under different pump flow. After this technique was combined with spectral analysis of Duplex Doppler imaging, the variable pump flow-based Doppler ultrasound method (VPFDUM) for Qa measurement was developed. This study compared the reproducibility and correlation of Qa measurements for three different methods-VPFDUM, ultrasound dilution method (UDM), and conventional Doppler ultrasound method (CDUM)-in 55 HD patients. The mean value of Qa by VPFDUM (870.8 +/- 412.0 ml/min) was close to that by UDM (868.6 +/- 417.9 ml/min) but higher than that by CDUM (either of the above values versus 685.1 +/- 303.6 ml/min; P < 0.005). The mean values of coefficient of variation were similar by VPFDUM (1.6%) and UDM (1.4%) but lower than that by CDUM (either of the above values versus 6.8%; P < 0.01). The correlation coefficient and intraclass correlation coefficient of the repeated Qa measurements by VPFDUM (0.985 and 0.993; P < 0.001) were also similar to those by UDM (0.992 and 0.995; P < 0.001) but slightly higher than those by CDUM (0.917 and 0.948; P < 0.005). Either the reproducibility of VPFDUM (r=0.98, P < 0.0001) or the correlation between VPFDUM and UDM (r=0.99, P < 0.0001) in Qa measurements is good. The unassisted patency of vascular access at 6 mo was significantly poorer in patients with Qa <500 ml/min than those with Qa >500 ml/min (13.6% versus 92.2%; P < 0.0001). In conclusion, VPFDUM is a noninvasive, accurate, and reliable procedure for Qa measurement and prediction of the prognosis of vascular access in HD patients.

  11. 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.

  12. 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. PMID:19175196

  13. 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.

  14. Micro-bubble transcranial Doppler ultrasound for exclusion of right-to-left circulatory shunts: why should we provide the service?

    PubMed

    Chiu, Albert H; Haluszkiewicz, Elvie; McAuliffe, William

    2014-08-01

    Micro-bubble transcranial Doppler ultrasound is a study used for the identification and quantification of a right-to-left circulatory shunt which can be implicated in stroke. It is an underused technique in many centres. Micro-bubble transcranial Doppler ultrasound is non-invasive, innocuous, quick and requires no fasting or sedation. Published literature also suggests almost perfect concordance with transoesophageal echocardiography and potentially greater sensitivity. We believe there is a great potential for neuroradiologists to provide this service as part of the diagnostic workup in patients with cryptogenic stroke.

  15. 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.

  16. 3D camera assisted fully automated calibration of scanning laser Doppler vibrometers

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

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

    SciTech Connect

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

    2014-05-27

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  19. Use of ultrasound Doppler to determine tooth vitality in a discolored tooth after traumatic injury: its prospects and limitations.

    PubMed

    Cho, Yong-Wook; Park, Sung-Ho

    2014-02-01

    When a tooth shows discoloration and does not respond to the cold test or electric pulp test (EPT) after a traumatic injury, its diagnosis can be even more difficult due to the lack of proper diagnostic methods to evaluate its vitality. In these case reports, we hope to demonstrate that ultrasound Doppler might be successfully used to evaluate the vitality of the tooth after trauma, and help reduce unnecessary endodontic treatments. In all three of the present cases, the teeth were discolored after traumatic injuries and showed negative responses to the cold test and EPT. However, they showed distinctive vital reactions in the ultrasound Doppler test during the whole observation period. In the first case, the tooth color returned to normal, and the tooth showed a positive response to the cold test and EPT at 10 wk after the injury. In the second case, the tooth color had returned to its normal shade at 10 wk after the traumatic injury but remained insensitive to the cold test and EPT. In the third case, the discoloration was successfully treated with vital tooth bleaching.

  20. Accuracy of velocity and shear rate measurements using pulsed Doppler ultrasound: a comparison of signal analysis techniques.

    PubMed

    Markou, C P; Ku, D N

    1991-01-01

    An experimental investigation was instituted to evaluate the performance of Doppler ultrasound signal processing techniques for measuring fluid velocity under well-defined flow conditions using a 10-MHz multigated pulsed ultrasound instrument. Conditions of fully developed flow in a rigid, circular tube were varied over a Reynolds number range between 500 and 8000. The velocity across the tube was determined using analog and digital zero crossing detectors and three digital spectrum estimators. Determination of the Doppler frequency from analog or digital zero crossing detectors gave accurate velocity values for laminar and moderately turbulent flow away from the wall (0.969 less than or equal to r less than or equal to 0.986). Three digital spectrum estimators, Fast Fourier Transform, Burg autoregressive method, and minimum variance method, were slightly more accurate than the zero crossing detector (0.984 less than or equal to r less than or equal to 0.994), especially at points close to the walls and with higher levels of turbulence. Steep velocity gradients and transit-time-effects from high velocities produced significantly larger errors in velocity measurement. Wall shear rate estimates were most precise when calculated using the position of the wall and two velocity points. The calculated wall shears were within 20%-30% of theoretically predicted values. PMID:1808798

  1. 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.

  2. Metachronous bilateral segmental testicular infarction: multi-parametric ultrasound imaging with grey-scale ultrasound, Doppler ultrasound, contrast-enhanced ultrasound (CEUS) and real-time tissue elastography (RTE).

    PubMed

    Patel, Ketul V; Huang, Dean Y; Sidhu, Paul S

    2014-09-01

    Segmental testicular infarction is a rare cause of acute scrotal pain. The appearances on grey-scale sonography are often indistinguishable from that of a testicular tumour, resulting in unnecessary orchiectomy. We report a case of acute bilateral testicular infarction, of unknown etiology, which was conservatively managed to resolution following a confident diagnosis achieved with the aid of contrast-enhanced ultrasound (CEUS) and real-time tissue elastography (RTE) along with conventional grey-scale and Doppler sonography. The evolving appearances on each of the sonographic modalities are described. We discuss the importance of complementing conventional sonography with CEUS and RTE in order to make a confident diagnosis and avoid unnecessary surgical intervention.

  3. Non-mechanical scanning laser Doppler velocimetry with sensitivity to direction of transverse velocity component using optical serrodyne frequency shifting

    NASA Astrophysics Data System (ADS)

    Maru, Koichi; Watanabe, Kento

    2014-05-01

    This paper proposes a non-mechanical axial scanning laser Doppler velocimeter (LDV) with sensitivity to the direction of the transverse velocity component using optical serrodyne frequency shifting. Serrodyne modulation via the electro-optic effect of a LiNbO3 (LN) phase shifter is employed to discriminate the direction of the transverse velocity component. The measurement position is scanned without any moving mechanism in the probe by changing the wavelength of the light input to the probe. The experimental results using a sensor probe setup indicate that both the scan of the measurement position and the introduction of directional sensitivity are successfully demonstrated.

  4. Successful stent implantation guided by intravascular ultrasound and a Doppler guidewire without contrast injection in a patient with allergy to iodinated contrast media.

    PubMed

    Okura, Hiroyuki; Nezuo, Shintaro; Yoshida, Kiyoshi

    2011-07-01

    Presence of allergy to iodinated contrast may prevent percutaneous coronary intervention (PCI) to be performed. We present a 76-year-old male with a history of allergic reaction to iodinated contrast who successfully underwent intravascular ultrasound (IVUS) and a Doppler guidewire-guided PCI. Stent size was determined based on IVUS. After PCI, stent expansion and a lack of edge dissection or incomplete apposition were confirmed by IVUS and a good antegrade coronary flow was confirmed by a Doppler guidewire. Thus, PCI without contrast injection under IVUS and a Doppler guidewire-guidance may be feasible in selected patients with allergy to iodinated contrast. PMID:21725127

  5. Neutral thermospheric dynamics observed with two scanning Doppler imagers: 3. Horizontal wind gradients

    NASA Astrophysics Data System (ADS)

    Anderson, C.; Conde, M.; McHarg, M. G.

    2012-05-01

    This is the third and final article in a series of papers reporting on observations of the 630.0 nm thermospheric airglow emission by two spatially separated scanning Doppler imagers (SDI's) in Alaska. In this article, bistatic winds derived from the combined measurements of both instruments in a region of field-of-view overlap were used to derive local-scale maps of horizontal neutral wind gradients. Averaged over the bistatic ‘field-of-view’, these gradient estimates were compared with the monostatic gradient estimates routinely produced by the two SDI's. The key findings to emerge from this study include: 1) the bistatic gradient estimate agreed very well with monostatic estimates for the majority of the time which, given the very different methods involved in each technique, gives us great confidence in our ability to measure F-region neutral wind gradients; 2) the strongest gradient was that which describes the magnetic meridional shear of the zonal wind, which is driven by momentum deposition from convecting ions; 3) vortical flow was more often observed than divergent flow, and both types of flow showed systematic variations with magnetic local time; 4) viscous heating due to non-negligible gradients was on the order of 10-11 Wm-3 which, while small compared to typical F-region Joule heating rates, may be comparable to particle heating, and in a time-integrated sense may be an appreciable source of heating.

  6. Neutral thermospheric dynamics observed with two scanning Doppler imagers: 2. Vertical winds

    NASA Astrophysics Data System (ADS)

    Anderson, C.; Conde, M.; McHarg, M. G.

    2012-03-01

    This article is the second in a series of three papers reporting on observations of the 630.0 nm thermospheric airglow emission by two spatially separated scanning Doppler imagers (SDI’s) in Alaska. In this article, line-of-sight wind measurements from these instruments in four common-volume regions lying along the great circle joining the two observatories have been used to derive estimates of the vertical wind in those common-volumes. These estimates are combined with the vertical winds measured directly in each of the station zeniths to resolve both the spatial and temporal variations of the vertical wind field. Data from four nights are presented as examples of the wave-like oscillations and frequently high spatial correlations that are observed. A statistical study of data from the full 19-night data set showed that the frequency of observing statistically significant correlation between vertical winds measured at separate locations decreased linearly with increasing separation. A linear fit to this trend indicated that for this particular location and orientation the largest separation over which statistically significant correlation would be expected to occur is approximately 540 km.

  7. Identification of pavement material properties using a scanning laser Doppler vibrometer

    NASA Astrophysics Data System (ADS)

    Hasheminejad, Navid; Vuye, Cedric; Van den Bergh, Wim; Dirckx, Joris; Leysen, Jari; Sels, Seppe; Vanlanduit, Steve

    2016-06-01

    This paper presents an inverse modeling approach to estimate mechanical properties of asphalt concrete (i.e. Young's modulus E, Poisson ratio ν and damping coefficients). Modal analysis was performed on an asphalt slab using a shaker to excite the specimen and an optical measurement system (a Scanning Laser Doppler Vibrometer or SLDV) to measure the velocity of a measurement grid on the surface of the slab. The SLDV has the ability to measure the vibration pattern of an object with high accuracy, short testing time and without making any contact. The measured data were used as inputs for a frequency domain model parameter estimation method (the Polymax estimator). Meanwhile, natural frequencies and damping ratios of the system were calculated using a Finite Element Modeling (FEM) method. Then, the Modal Assurance Criterion (MAC) was used to pair the mode shapes of the structure determined by measurements and estimated by FEM. By changing the inputs of the FEM analysis (E, ν and damping coefficients of the material) iteratively and minimizing the discrepancy between paired natural frequencies and damping ratios of the system estimated using the Polymax estimator and calculated by FEM, the Young's modulus, Poisson ratio and damping coefficients of the asphalt slab were estimated.

  8. Motion of tympanic membrane in guinea pig otitis media model measured by scanning laser Doppler vibrometry.

    PubMed

    Wang, Xuelin; Guan, Xiying; Pineda, Mario; Gan, Rong Z

    2016-09-01

    Otitis media (OM) is an inflammatory or infectious disease of the middle ear. Acute otitis media (AOM) and otitis media with effusion (OME) are the two major types of OM. However, the tympanic membrane (TM) motion differences induced by AOM and OME have not been quantified in animal models in the literature. In this study, the guinea pig AOM and OME models were created by transbullar injection of Streptococcus pneumoniae type 3 and lipopolysaccharide, respectively. To explore the effects of OM on the entire TM vibration, the measurements of full-field TM motions were performed in the AOM, OME and untreated control ears by using scanning laser Doppler vibrometry (SLDV). The results showed that both AOM and OME generally reduced the displacement peak and produced the traveling-wave-like motions at relatively low frequencies. Compared with the normal ear, OME resulted in a significant change of the TM displacement mainly in the inferior portion of the TM, and AOM significantly affected the surface motion across four quadrants. The SLDV measurements provide more insight into sound-induced TM vibration in diseased ears. PMID:27490002

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

    PubMed

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

    2010-01-18

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

  10. Nonperturbing measurements of spatially distributed underwater acoustic fields using a scanning laser Doppler vibrometer.

    PubMed

    Harland, Andy R; Petzing, Jon N; Tyrer, John R

    2004-01-01

    Localized changes in the density of water induced by the presence of an acoustic field cause perturbations in the localized refractive index. This relationship has given rise to a number of nonperturbing optical metrology techniques for recording measurement parameters from underwater acoustic fields. A method that has been recently developed involves the use of a Laser Doppler Vibrometer (LDV) targeted at a fixed, nonvibrating, plate through an underwater acoustic field. Measurements of the rate of change of optical pathlength along a line section enable the identification of the temporal and frequency characteristics of the acoustic wave front. This approach has been extended through the use of a scanning LDV, which facilitates the measurement of a range of spatially distributed parameters. A mathematical model is presented that relates the distribution of pressure amplitude and phase in a planar wave front with the rate of change of optical pathlength measured by the LDV along a specifically orientated laser line section. Measurements of a 1 MHz acoustic tone burst generated by a focused transducer are described and the results presented. Graphical depictions of the acoustic power and phase distribution recorded by the LDV are shown, together with images representing time history during the acoustic wave propagation.

  11. [Usefulness of Doppler ultrasound in the diagnosis of renal artery stenosis in hypertensive children. Two case reports and review of the literature].

    PubMed

    Favilli, Silvia; Capuzzo, Leila; Pollini, Iva; Calabri, Giovanni; De Simone, Luciano; Pela, Ivana; Seracini, Daniela; Bini, Roberta M

    2004-06-01

    Renal artery stenosis, mainly due to fibromuscular dysplasia, is the second more common cause of arterial hypertension in children, after aortic coarctation. Two children sent to our Center of Pediatric Cardiology, one for arterial hypertension and the other for renal failure (associated with severe hypertension not previously recognized) are reported. In both of them the diagnosis of renal artery stenosis was established at Doppler ultrasonography, performed at the time of Doppler echocardiography. Both children were submitted to successful percutaneous transluminal angioplasty; short- and medium-term results are evaluated by Doppler ultrasonography. Renovascular disease is a potentially curable cause of renal artery stenosis in children. Renal artery evaluation by Doppler ultrasound is recommended in all hypertensive children who undergo Doppler echocardiography. PMID:15471155

  12. 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.

  13. Why Current Doppler Ultrasound Methodology Is Inaccurate in Assessing Cerebral Venous Return: The Alternative of the Ultrasonic Jugular Venous Pulse

    PubMed Central

    2016-01-01

    Assessment of cerebral venous return is growing interest for potential application in clinical practice. Doppler ultrasound (DUS) was used as a screening tool. However, three meta-analyses of qualitative DUS protocol demonstrate a big heterogeneity among studies. In an attempt to improve accuracy, several authors alternatively measured the flow rate, based on the product of the time average velocity with the cross-sectional area (CSA). However, also the quantification protocols lacked of the necessary accuracy. The reasons are as follows: (a) automatic measurement of the CSA assimilates the jugular to a circle, while it is elliptical; (b) the use of just a single CSA value in a pulsatile vessel is inaccurate; (c) time average velocity assessment can be applied only in laminar flow. Finally, the tutorial describes alternative ultrasound calculation of flow based on the Womersley method, which takes into account the variation of the jugular CSA overtime. In the near future, it will be possible to synchronize the electrocardiogram with the brain inflow (carotid distension wave) and with the outflow (jugular venous pulse) in order to nicely have a noninvasive ultrasound picture of the brain-heart axis. US jugular venous pulse may have potential use in neurovascular, neurocognitive, neurosensorial, and neurodegenerative disorders. PMID:27006525

  14. Ultrasound M-mode assessment of diaphragmatic kinetics by anterior transverse scanning in healthy subjects.

    PubMed

    Testa, Americo; Soldati, Gino; Giannuzzi, Rosangela; Berardi, Silvia; Portale, Grazia; Gentiloni Silveri, Nicolò

    2011-01-01

    The purpose of this study was to set an effective standardized method to assess diaphragmatic kinetics by ultrasound. Forty healthy volunteers were submitted to a B- and M-mode ultrasound study using a convex transducer positioned in the subcostal anterior area for transverse scanning. Ultrasound examination was completed in 38/40 cases (95%), spending on average <10 min for examination. The resting and forced diaphragmatic excursions were 18.4 ± 7.6 and 78.8 ± 13.3 mm, respectively, unrelated to demographic or anthropometric parameters: intraobserver variability on three successive measurements resulted in 6.0% and in 3.9%, respectively. An inexperienced sonographer completed the ultrasound examination in 37/40 cases, spending on average >15 min, with significant, although marginal, interobserver variability (31.9% and 14.7% for resting and forced diaphragmatic excursion, respectively). Bedside ultrasonography by an anterior subcostal transverse scanning on semi-recumbent patient proves to be a safe, feasible, reliable, fast, relatively easy and reproducible way to assess diaphragm movement.

  15. Ultrasound scanning of post-operative wounds--the risks of cross-infection.

    PubMed

    Spencer, P; Spencer, R C

    1988-05-01

    Ultrasound scanning of surgical wounds is an established procedure for the detection of abscesses. The possible risks of cross-infection resulting from this technique were examined by testing the sterility of the ultrasound probes, the coupling gel and the stand-off medium Kitecko (3 M). The coupling gel was also assessed for any bactericidal properties. Sixty-six per cent of swabs taken from machines in constant use and 33% of the total number of swabs taken were contaminated with skin flora including Staphylococcus aureus. Sterility was achieved using a 70% alcohol wipe. The coupling gel was inherently sterile but had no bactericidal action. The solid stand-off medium Kitecko grew Enterobacteriaceae and Pseudomonas species. The implications of these findings in relation to scanning post-operative wounds are discussed.

  16. Diagnosis of abdominal abscesses with computed tomography, ultrasound, and /sup 111/In leukocyte scans

    SciTech Connect

    Knochel, J.Q.; Koehler, P.R.; Lee, T.G.; Welch, D.M.

    1980-11-01

    Computed tomography (CT), ultrasound, and /sup 111/In-labeled leukocyte scans are all used in the evaluation of abdominal abscesses. In this study, 170 patients in whom one, two, or all three of these modalities were used were retrospectively reviewed. Diagnostic accuracy of 96% for CT, 90% for ultrasound, and 92% for /sup 111/In leukocyte scans was achieved. It was often necessary to use more than one modality to arrive at a correct diagnosis. The advantages and disadvantages as well as the causes for false positive or false negative interpretations of each of these modalities are reviewed. Analysis of the different examinations resulted in a suggested sequence by which patients can be examined, based upon their clinical condition. Patients who are not critically ill and/or who have no localizing signs should be studied first with /sup 111/In-labeled leukocyte scans. If, however, localizing signs are present or the patient's condition necessitates prompt intervention, CT or ultrasound should be the first study performed.

  17. Do Regular Ultrasound Scans Reduce the Incidence of Stillbirth in Women with Apparently Normal Pregnancies?

    PubMed Central

    Toner, Brenda; Mone, Fionnuala

    2015-01-01

    Objective To determine the incidence of stillbirth in women who have regular ante-natal ultrasound compared to those that have infrequent scans in a low risk population. Study Design A retrospective observational study was performed in a tertiary center with 5,700 deliveries per annum. Data on all deliveries was collected via the Northern Ireland Maternity System Database. Only women with an apparently low risk pregnancy were included. Women who had private antenatal care often had frequent scans in the third trimester. Women who did not have private antenatal care often had scans infrequently. The still birth rate was calculated for both groups of women from 2007 to 2011 and compared using a Chi-squared analysis Results Our study included 23,519 ‘low-risk’ deliveries spanning 2007-2011. This included 2,088 (9%) patients who had frequent ultrasound surveillance and delivery at term and 21,431 (91%) patients who did not. The overall stillbirth rate was 0.34% and 0.20% respectively which was not statistically different (p=0.31). Conclusion There is no difference in the rate of stillbirth between patients who have more frequent ante-natal ultrasound surveillance compared with those who do not in a low risk population. PMID:26170484

  18. Assessment of the Effects of Low-Level Laser Therapy on the Thyroid Vascularization of Patients with Autoimmune Hypothyroidism by Color Doppler Ultrasound

    PubMed Central

    Höfling, Danilo Bianchini; Chavantes, Maria Cristina; Juliano, Adriana G.; Cerri, Giovanni G.; Knobel, Meyer; Yoshimura, Elisabeth M.; Chammas, Maria Cristina

    2012-01-01

    Background. Chronic autoimmune thyroiditis (CAT) frequently alters thyroid vascularization, likely as a result of the autoimmune process. Objective. To evaluate the effects of low-level laser therapy (LLLT) on the thyroid vascularization of patients with hypothyroidism induced by CAT using color Doppler ultrasound parameters. Methods. In this randomized clinical trial, 43 patients who underwent levothyroxine replacement for CAT-induced hypothyroidism were randomly assigned to receive either 10 sessions of LLLT (L group, n = 23) or 10 sessions of a placebo treatment (P group, n = 20). Color Doppler ultrasounds were performed before and 30 days after interventions. To verify the vascularity of the thyroid parenchyma, power Doppler was performed. The systolic peak velocity (SPV) and resistance index (RI) in the superior (STA) and inferior thyroid arteries (ITAs) were measured by pulsed Doppler. Results. The frequency of normal vascularization of the thyroid lobes observed in the postintervention power Doppler examination was significantly higher in the L than in the P group (P = 0.023). The pulsed Doppler examination revealed an increase in the SPV of the ITA in the L group compared with the P group (P = 0.016). No significant differences in the SPV of the STA and in the RI were found between the groups. Conclusion. These results suggest that LLLT can ameliorate thyroid parenchyma vascularization and increase the SPV of the ITA of patients with hypothyroidism caused by CAT. PMID:23316383

  19. Proof-of-Concept Studies for Marker-Based Ultrasound Doppler Analysis of Microvascular Anastomoses in a Modified Large Animal Model.

    PubMed

    Coon, Devin; Chen, Lei; Boctor, Emad M; Prince, Jerry L; Bojovic, Branko

    2016-05-01

    Background Despite attempts to solve the problem of flap monitoring, assessing the patency of vascular anastomoses postoperatively remains challenging. In addition, experimental data suggest that near-total vessel occlusion is necessary to produce significant changes in clinical appearance or monitoring devices. We sought to develop an ultrasound-based system that would provide definitive data on anastomotic function. Methods A system was developed consisting of a resorbable marker made from poly-lactic-co-glycolic acid (PLGA) implanted during the time of surgery coupled with ultrasound software to detect the anastomotic site and perform Doppler flow analysis. Surgical procedures consisting of microvascular free tissue transfer or femoral vessel cutdown were performed followed by marker placement, closure, and ultrasound monitoring. Transient vascular occlusion was produced via vessel-loop constriction. Permanent thrombosis was induced via an Arduino-controlled system applying current to the vessel intima. Results Four surgeries (one femoral vessel cutdown and three microvascular tissue transfer) were successfully performed in Yorkshire swine. The markers were readily visualized under ultrasound and provided a bounding area for Doppler analysis as well as orientation guidance. Transient spasm and partial occlusion were detected based on changes in Doppler data, while complete occlusion was evident as the total loss of color Doppler. Conclusion In this preliminary report, we have conceptualized and developed a novel system that enables the real-time visualization of vascular pedicle flow at the bedside using Doppler ultrasound and a surgically implanted marker. In a large animal model, use of the system allowed identification of the anastomosis, flow analysis, and real-time detection of flow loss. PMID:26645155

  20. High-frequency Ultrasound Doppler System for Biomedical Applications with a 30 MHz Linear Array

    PubMed Central

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

    2008-01-01

    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 animal. 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 directly fed 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 PC. The Doppler spectrogram was displayed on a PC in real time. The two-way beam-widths were determined to be 160 μm to 320 μm when the array was electronically focused at different focal points at depths from 5–10 mm. A micro flow phantom, consisting of a polyimide tube with inner diameter of 127 μm, 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 μm 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 μm, 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. PMID:17993243

  1. Multiple-Site Hemodynamic Analysis of Doppler Ultrasound with an Adaptive Color Relation Classifier for Arteriovenous Access Occlusion Evaluation

    PubMed Central

    Wu, Jian-Xing; Du, Yi-Chun; Wu, Ming-Jui; Li, Chien-Ming; Lin, Chia-Hung; Chen, Tainsong

    2014-01-01

    This study proposes multiple-site hemodynamic analysis of Doppler ultrasound with an adaptive color relation classifier for arteriovenous access occlusion evaluation in routine examinations. The hemodynamic analysis is used to express the properties of blood flow through a vital access or a tube, using dimensionless numbers. An acoustic measurement is carried out to detect the peak-systolic and peak-diastolic velocities of blood flow from the arterial anastomosis sites (A) to the venous anastomosis sites (V). The ratio of the supracritical Reynolds (Resupra) number and the resistive (Res) index quantitates the degrees of stenosis (DOS) at multiple measurement sites. Then, an adaptive color relation classifier is designed as a nonlinear estimate model to survey the occlusion level in monthly examinations. For 30 long-term follow-up patients, the experimental results show the proposed screening model efficiently evaluates access occlusion. PMID:24892039

  2. 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.

  3. Very different performance of the power Doppler modalities of several ultrasound machines ascertained by a microvessel flow phantom

    PubMed Central

    2013-01-01

    Introduction In many patients with rheumatoid arthritis (RA) subclinical disease activity can be detected with ultrasound (US), especially using power Doppler US (PDUS). However, PDUS may be highly dependent on the type of machine. This could create problems both in clinical trials and in daily clinical practice. To clarify how the PDUS signal differs between machines we created a microvessel flow phantom. Methods The flow phantom contained three microvessels (150, 1000, 2000 microns). A syringe pump was used to generate flows. Five US machines were used. Settings were optimised to assess the lowest detectable flow for each US machine. Results The minimal detectable flow velocities showed very large differences between the machines. Only two of the machines may be able to detect the very low flows in the capillaries of inflamed joints. There was no clear relation with price. One of the lower-end machines actually performed best in all three vessel sizes. Conclusions We created a flow phantom to test the sensitivity of US machines to very low flows in small vessels. The sensitivity of the power Doppler modalities of 5 different machines was very different. The differences found between the machines are probably caused by fundamental differences in processing of the PD signal or internal settings inaccessible to users. Machines considered for PDUS assessment of RA patients should be tested using a flow phantom similar to ours. Within studies, only a single machine type should be used. PMID:24286540

  4. A multi-dimensional approach for describing internal bleeding in an artery: implications for Doppler ultrasound guiding HIFU hemostasis

    NASA Astrophysics Data System (ADS)

    Yang, Di; Zhang, Dong; Guo, Xiasheng; Gong, Xiufen; Fei, Xingbo

    2008-09-01

    Doppler ultrasound has shown promise in detecting and localizing internal bleeding. A mathematical approach was developed to describe the internal bleeding of the injured artery surrounded by tissue. This approach consisted of a two-dimensional (2D) model describing the injured vessel and a one-dimensional model (1D) mimicking the downstream of the vessel system. The validity of this approach was confirmed by both the numerical simulation and in vivo measurement of a normal porcine femoral artery. Furthermore, the artery was injured using a 16-gauge needle to model a penetrating injury. The velocity waveform at the puncture site was modeled and compared with those at the upstream and downstream of the artery. The results demonstrated that there was a significant increase in magnitude and a phase lag for the peak systolic velocity at the injury site. These results were qualitatively in agreement with the in vivo experiment. Flow turbulence indicated by this approach was also observed in a color Doppler image in the form of a checkered color pattern. This approach might be useful for quantitative internal bleeding detection and localization. Also, the phase lag of the peak systolic velocity was indicated to be potential in the application of internal bleeding detection.

  5. Using the discrete Gabor expansion for the Doppler ultrasound signal processing.

    PubMed

    Ghofrani, S; Ayatollahi, A; Shamsollahi, M B

    2003-01-01

    In this paper we have synthesized the Doppler signal with a known time varying mean frequency, then used the orthogonal-like Discrete Gabor Transform (DGT) and the spectrogram for analyzing the signal. Mean square error has been computed for each method respectively and at last we have analyzed the real clinical signal too.

  6. 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.

  7. Measurement and Visualization of Three-Dimensional Vertebra Shape by Freehand Ultrasound Scanning

    NASA Astrophysics Data System (ADS)

    Kohyama, Kazuhiro; Yasumuro, Yoshihiro; Imura, Masataka; Manabe, Yoshitsugu; Oshiro, Osamu; Moroi, Keishichiro; Chihara, Kunihiro

    2005-06-01

    Paracentesis is a common operation for pain clinics and spinal anesthetics administration and requires empirical training and flexible skills to cope with the various cases of individual patients. We propose a method of measuring and visualizing three-dimensional vertebra shapes for assisting anesthesiologists, by an ultrasound imaging technique that is prevalent in many hospitals and has no harmful risks to the human body. The proposed system enables anesthesiologists to investigate vertebra shapes by freehand probing. Three-dimensional reconstruction and graphical rendering can be performed by monitoring the motion of the ultrasound probe and registering the scanned echography into the identical three-dimensional space. Considering the echography imaging features, volume rendering of hard tissue surfaces is achieved and interactive measurement is possible. This paper describes the practicability of the proposed method based on experimental measurement of both phantom and real lumbar vertebre and sacra.

  8. [Use of Doppler ultrasound in the examination of the extent of venous angiomas].

    PubMed

    Van Der Molen, H R

    1976-01-01

    After emphasizing that the treatment of a strawberry naevus in a newborn is usually unnecessary, the author shows the value of the Sonar Doppler in delimiting the extent of pseudovaricose and cavernous, venous angiomas. Arterio-venous fistulas above a certain size can be localized by this procedure. Sometimes these disappear spontaneously (traumatism, thrombosis). On the other hand, the delicate arteriovenous fistulas found in cases of the Klippel and Trenaunay triad are inaccessible to this procedure.

  9. Multigate transcranial Doppler ultrasound system with real-time embolic signal identification and archival.

    PubMed

    Fan, Lingke; Boni, Enrico; Tortoli, Piero; Evans, David H

    2006-10-01

    An integrated system for acquisition and processing of intracranial and extracranial Doppler signals and automatic embolic signal detection has been developed. The hardware basis of the system is a purpose-built acquisition/processing board that includes a multigate Doppler unit controlled through a computer. The signal-processing engine of the system contains a fast Fourier transform (FFT)-based, spectral-analysis unit and an embolic signal-detection unit using expert system reasoning theory. The system is designed so that up to four receive gates from a single transducer can be used to provide useful reasoning information to the embolic signal-detection unit. Alternatively, two transducers can be used simultaneously, either for bilateral transcranial Doppler (TCD) investigations or for simultaneous intra- and extracranial investigation of different arteries. The structure of the software will allow the future implementation of embolus detection algorithms that use the information from all four channels when a single transducer is used, or of independent embolus detection in two sets of two channels when two transducers are used. The user-friendly system has been tested in-vitro, and it has demonstrated a 93.6% sensitivity for micro-embolic signal (MES) identification. Preliminary in-vivo results also are encouraging. PMID:17036793

  10. The pulsed Doppler ultrasound flowmeter: experimental evaluation of velocity accuracy and range resolution.

    PubMed

    Griffith, J M; McLeod, F D; Leroy, A F

    1977-01-01

    Accurate quantitation of blood flow patterns, particularly in the physiological state, is important to the successful study of several problems in biomedical research. The pulsed Doppler ultrasonic flowmeter offers promise of overcoming some of the difficulties present in other methods. This flowmeter can be either implantable or noninvasive. Although a number of papers describe important design criteria, the design or selection of a Doppler system for a given task remains a complex matter involving many compromises based on theoretical considerations and very limited data. Experimental data from well-defined flows are needed to help identify those areas in which ultrasonic flowmeters can be most useful. This paper defines and evaluates two important parameters for the pulsed Doppler ultrasonic flowmeter by comparing experimental results with those predicted theorectically. The first parameter is velocity accuracy; the second parameter is range resolution. Findings show that centerline flow velocities in circular tubes can be estimated to within a few percent of the correct value, and that a 1.5-mm range resolution can be realized with the system tested.

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

    PubMed

    Emenheiser, J C; Tait, R G; Shackelford, S D; Kuehn, L A; Wheeler, T L; Notter, D R; Lewis, R M

    2014-09-01

    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 BCS to each cow on 2 consecutive days. Ultrasound traits were backfat thickness (UBFT), LM area (ULMA), body wall thickness (UBWT), rump fat depth (URFD), rump muscle depth (URMD), and intramuscular fat (UIMF; %). Cows were then harvested. Carcass traits were HCW, backfat thickness (CBFT), LM area (CLMA), body wall thickness (CBWT), and marbling score (CMS). Correlations between consecutive live measurements were greatest for subcutaneous fat (r > 0.94) and lower for BCS (r > 0.74) and URMD (r > 0.66). Repeatability bias differed from 0 for only 1 technician for URMD and UIMF (P < 0.01). Technicians differed in repeatability SE for only ULMA (P < 0.05). Correlations between live and carcass measurements were high for backfat and body wall thickness (r > 0.90) and slightly less for intramuscular fat and LM area (r = 0.74 to 0.79). Both technicians underestimated all carcass traits with ultrasound, but only CBFT and CBWT prediction bias differed from 0 (P < 0.05). Technicians had similar prediction SE for all traits (P > 0.05). Technician effects generally explained <1% of the total variation in precision. After accounting for technician, animal effects explained 50.4% of remaining variation in differences between repeated BCS (P < 0.0001) but were minimal for scan differences. When cows with mean BCS <4 or >7 were removed, the portion of remaining variation between repeated measurements defined by animal effects increased for most traits and was significant for UBFT and URFD (P = 0.03). Technician effects explained trivial variation in accuracy (P > 0.24). Animal effects explained 87.2, 75.2, and 81.7% (P < 0.0001) of variation remaining for CBFT, CLMA, and CBWT prediction

  12. Ultrasound

    MedlinePlus

    Ultrasound is a type of imaging. It uses high-frequency sound waves to look at organs and ... liver, and other organs. During pregnancy, doctors use ultrasound to view the fetus. Unlike x-rays, ultrasound ...

  13. Ultrasound

    MedlinePlus

    Ultrasound is a useful procedure for monitoring the baby's development in the uterus. Ultrasound uses inaudible sound waves to produce a two- ... sound waves and appear dark or black. An ultrasound can supply vital information about a mother's pregnancy ...

  14. General Ultrasound Imaging

    MedlinePlus

    ... collects the sounds that bounce back and a computer then uses those sound waves to create an ... types of Doppler ultrasound: Color Doppler uses a computer to convert Doppler measurements into an array of ...

  15. Practical Use of Ultrasound Scan in Small Ruminant Medicine and Surgery.

    PubMed

    Scott, Phil

    2016-03-01

    Modern portable ultrasound scan machines provide the veterinary clinician with an inexpensive and noninvasive method to further examine sheep on farms, which should take no more than 5 minutes with the results available immediately. Repeat examinations allow monitoring of the disease process and assessment of therapy. 5 MHz linear array scanners can be used for most organs except the heart and right kidney. Transthoracic ultrasonography is particularly useful for critical evaluation of lung and pleural pathologies. Transabdominal ultrasonographic examination can readily identify distended urinary bladder and advanced hydronephrosis.

  16. 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

  17. Remote Sensing of Wind Fields and Aerosol Distributions with Airborne Scanning Doppler Lidar

    NASA Technical Reports Server (NTRS)

    Rothermel, Jeffry; Cutten, Dean R.; Goodman, H. Michael (Technical Monitor)

    2000-01-01

    The coherent Doppler lidar, when operated from an airborne platform, offers a unique measurement capability for study of atmospheric and surface processes and feature. This is especially true for scientific objectives requiring measurements in optically-clear air, where other remote sensing technologies such as Doppler radar are at a disadvantage in terms of spatial resolution and coverage. 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 about a 1 Joule/pulse (eyesafe) lidar transceiver, telescope, scanner, inertial measurement unit, and operations control 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 about 1 km; vertical resolution is even finer. Winds are obtained by measuring backscattered, Doppler-shifted laser radiation from naturally-occurring aerosol particles (on an order of 1 micron in diameter). Measurement coverage depends on aerosol spatial distribution and concentration. Velocity accuracy has been verified to be about 1 m/s. A variety of applications has 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; an upper tropospheric jet stream; the angular dependence of sea surface scattering; and in-flight radiometric calibration using the surface of White Sands National Monument. In 1998, the

  18. Glomus tumour of the hallux: diagnosis by Doppler-shift ultrasound and digital subtraction angiography.

    PubMed Central

    Kreel, L.; Thornton, A.; Pardy, B. J.

    1986-01-01

    A case is presented of a glomangioma with typical history and clinical findings, proven by operation and histology. Unique radiographic features are demonstrated including visualization of the tumour on a soft tissue radiograph and associated hyperaemic bone changes, continuous wave Doppler results indicating hyperaemia and an arterio-venous malformation, and the clear demonstration of the tumour in both frontal and lateral views was possible by intra-arterial digital subtraction angiography (DSA) under local anaesthesia. Fibrous dysplasia of a femur was an incidental finding. Images Figure 1 Figure 3 Figure 4 Figure 5 Figure 6 PMID:3018711

  19. 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.

  20. 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

    2014-09-01

    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. PMID:25321553

  1. 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

    2014-09-01

    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.

  2. Semen quality, testicular B-mode and Doppler ultrasound, and serum testosterone concentrations in dogs with established infertility.

    PubMed

    de Souza, Mírley Barbosa; England, Gary C W; Mota Filho, Antônio Cavalcante; Ackermann, Camila Louise; Sousa, Carmen Vládia Soares; de Carvalho, Gabriela Guedelha; Silva, Herlon Victor Rodrigues; Pinto, José Nicodemos; Linhares, Jussiara Candeira Spíndola; Oba, Eunice; da Silva, Lúcia Daniel Machado

    2015-09-15

    Retrospective examination of breeding records enabled the identification of 10 dogs of normal fertility and 10 dogs with established infertility of at least 12 months of duration. Comparisons of testicular palpation, semen evaluation, testicular ultrasound examination, Doppler ultrasound measurement of testicular artery blood flow, and measurement of serum testosterone concentration were made between the two groups over weekly examinations performed on three occasions. There were no differences in testicular volume (cm(3)) between the two groups (fertile right testis = 10.77 ± 1.66; fertile left testis = 12.17 ± 2.22); (infertile right testis = 10.25 ± 3.33; infertile left testis = 11.37 ± 3.30), although the infertile dogs all had subjectively softer testes compared with the fertile dogs. Infertile dogs were either azoospermic or when they ejaculated, they had lower sperm concentration, sperm motility, and percentage of morphologically normal spermatozoa than fertile dogs. Furthermore, infertile dogs had reduced sperm membrane integrity measured via the hypoosmotic swelling test. Infertile dogs had significantly lower basal serum testosterone concentrations (1.40 ± 0.62 ng/mL) than fertile dogs (1.81 ± 0.87 ng/mL; P < 0.05). There were subjective differences in testicular echogenicity in some of the infertile dogs, and important differences in testicular artery blood flow with lower peak systolic and end-diastolic velocities measured in the distal supratesticular artery, marginal testicular artery, and intratesticular artery of infertile dogs (P < 0.05). Notably, resistance index and pulsatility index did not differ between infertile and fertile dogs. These findings report important differences between infertile and fertile dogs which may be detected within an expanded breeding soundness examination.

  3. Wigner-Ville distribution and Gabor transform in Doppler ultrasound signal processing.

    PubMed

    Ghofrani, S; Ayatollahi, A; Shamsollahi, M B

    2003-01-01

    Time-frequency distributions have been used extensively for nonstationary signal analysis, they describe how the frequency content of a signal is changing in time. The Wigner-Ville distribution (WVD) is the best known. The draw back of WVD is cross-term artifacts. An alternative to the WVD is Gabor transform (GT), a signal decomposition method, which displays the time-frequency energy of a signal on a joint t-f plane without generating considerable cross-terms. In this paper the WVD and GT of ultrasound echo signals are computed analytically.

  4. Matlab-based interface for the simultaneous acquisition of force measures and Doppler ultrasound muscular images.

    PubMed

    Ferrer-Buedo, José; Martínez-Sober, Marcelino; Alakhdar-Mohmara, Yasser; Soria-Olivas, Emilio; Benítez-Martínez, Josep C; Martínez-Martínez, José M

    2013-04-01

    This paper tackles the design of a graphical user interface (GUI) based on Matlab (MathWorks Inc., MA), a worldwide standard in the processing of biosignals, which allows the acquisition of muscular force signals and images from a ultrasound scanner simultaneously. Thus, it is possible to unify two key magnitudes for analyzing the evolution of muscular injuries: the force exerted by the muscle and section/length of the muscle when such force is exerted. This paper describes the modules developed to finally show its applicability with a case study to analyze the functioning capacity of the shoulder rotator cuff. PMID:23176896

  5. 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.

  6. Turbulence in wind turbine wakes under different atmospheric conditions from static and scanning Doppler LiDARs

    NASA Astrophysics Data System (ADS)

    Kumer, Valerie; Reuder, Joachim

    2016-04-01

    Wake characteristics are of great importance for wind park performances and turbine loads. Wind tunnel experiments helped to validate wake model simulations under neutral atmospheric conditions. However, recent studies show strongest wake characteristics and power losses in stable atmospheric conditions. Considering all three occurring atmospheric conditions this study presents a turbulence analysis of wind turbine wake flows measured by static and scanning Doppler LiDARs at the coast of the Netherlands. We use data collected by three Windcubes v1, a scanning Windcube 100S and sonic anemometers during the Wind Turbine Wake Experiment - Wieringermeer (WINTWEX-W). Turbulence parameters such as Turbulence Intensity (TI) and turbulent kinetic energy (TKE) are retrieved from the collected raw data. Results show highest turbulence on the flanks of the wake where strong wind shear dominates. On average the spatial turbulence distribution becomes more homogeneous with conical areas of enhanced TI. Highest turbulence and strongest wind deficits occur during stable weather conditions. Despite the ongoing research on the reliability of turbulence retrievals of Doppler LiDAR data, the results are consistent with sonic anemometer measurements and show promising opportunities for a qualitative study of wake characteristics such as wake strength and wake peak frequencies.

  7. Detection of right-to-left shunt with ultrasound contrast agent and transcranial Doppler sonography.

    PubMed

    Jauss, M; Zanette, E

    2000-01-01

    An international Consensus Meeting to determine a standard in the examination technique for the detection of right-to-left shunt (RLS) using contrast transcranial Doppler sonography (TCD) led to the following recommendations to standardize the examination procedure: The patient should be prepared with an 18-gauge needle inserted into the cubital vein and should be in the supine position. Insonation of at least one middle cerebral artery (MCA) using TCD is performed. The contrast agent is prepared using 9 ml isotonic saline solution and 1 ml air mixed with a three-way stopcock by exchange of saline/air mixture between the syringes and injected as a bolus. In case of little or no detection of microbubbles (MB) in the MCA under basal conditions, the examination will be repeated using the Valsalva maneuver (VM). Contrast agent will be injected 5 s before the start of the VM; the overall VM duration should be 10 s. The patient should start the VM on examiner's command. The strength of the VM can be controlled by peak flow velocity of the Doppler curve. The time when the first MB appears at the MCA level will be noted. A four-level categorization according to the MB count should be applied: (1) 0 MB (negative result); (2) 1-10 MB; (3) >10 MB and no curtain, and (4) curtain. ('Curtain' refers to a shower of MB, where a single bubble cannot be identified.) The results should be documented for basal condition and VM testing separately. The clinical significance of the diagnosis of a RLS in a particular patient is not fully evaluated and requires further studies. A minimum amount of MB suggestive of a clinical relevant RLS is not yet established. It probably depends on interindividual differences in hemodynamics that are currently not fully understood. Transesophageal echocardiography remains the gold standard for detection of a patent foramen ovale or an atrial septum defect. However, TCD with a contrast agent has been turned out as a potential method to diagnose a RLS in

  8. Three-dimensional reconstruction of multiplane transesophageal rotational scanning echocardiography

    NASA Astrophysics Data System (ADS)

    He, Aijun; Wang, Tianfu; Zheng, Changqiong; Li, Deyu; Yin, Lixue; Zheng, Yi

    2001-09-01

    The present paper studies the method of 3D reconstruction of multiplane transesophageal rotational scanning echocardiography. According to the characteristic of rotational scanning echocardiography, a direct matching interpolation method is exploited to reconstruct regular volume data from distributed ultrasound scanning points. The whole system is developed and clinical ultrasound data is tested for this method. The volume rendering results show that the proposed method is valid and effective. At last, the possibility of functional reconstruction based on tissue Doppler imaging is explored.

  9. Reduced cerebral embolic signals in beating heart coronary surgery detected by transcranial Doppler ultrasound.

    PubMed

    Watters, M P; Cohen, A M; Monk, C R; Angelini, G D; Ryder, I G

    2000-05-01

    Cerebral emboli detected by transcranial Doppler imaging were recorded in 20 patients undergoing multiple-vessel coronary artery bypass surgery, either with or without cardiopulmonary bypass, in a prospective unblinded comparative study. Emboli were recorded continuously from the time of pericardial incision until 10 min after the last aortic instrumentation. The numbers of coronary grafts and of aortic clampings were also documented. Patients undergoing revascularization with cardiopulmonary bypass had more emboli (median 79, range 38-876) per case compared with patients having off-pump surgery (median 3, range 0-18). No clinically detectable neurological deficits were seen in either group. Beating heart surgery is associated with fewer emboli than coronary surgery with cardiopulmonary bypass. Further research is necessary to determine whether a smaller number of emboli alters the incidence of neurological deficit after cardiac surgery.

  10. Ultrasound Doppler renal resistive index: a useful tool for the management of the hypertensive patient

    PubMed Central

    Viazzi, Francesca; Leoncini, Giovanna; Derchi, Lorenzo E.; Pontremoli, Roberto

    2014-01-01

    The Doppler-derived renal resistive index has been used for years in a variety of clinical settings such as the assessment of chronic renal allograft rejection, detection and management of renal artery stenosis, evaluation of progression risk in chronic kidney disease, differential diagnosis in acute and chronic obstructive renal disease, and more recently as a predictor of renal and global outcome in the critically ill patient. More recently, evidence has been accumulating showing that an increased renal resistive index not only reflects changes in intrarenal perfusion but is also related to systemic hemodynamics and the presence of subclinical atherosclerosis, and may thus provide useful prognostic information in patients with primary hypertension. On the basis of these results, the evaluation of renal resistive index has been proposed in the assessment and management of patients with primary hypertension to complement other signs of renal abnormalities. PMID:24172238

  11. Reduced cerebral embolic signals in beating heart coronary surgery detected by transcranial Doppler ultrasound.

    PubMed

    Watters, M P; Cohen, A M; Monk, C R; Angelini, G D; Ryder, I G

    2000-05-01

    Cerebral emboli detected by transcranial Doppler imaging were recorded in 20 patients undergoing multiple-vessel coronary artery bypass surgery, either with or without cardiopulmonary bypass, in a prospective unblinded comparative study. Emboli were recorded continuously from the time of pericardial incision until 10 min after the last aortic instrumentation. The numbers of coronary grafts and of aortic clampings were also documented. Patients undergoing revascularization with cardiopulmonary bypass had more emboli (median 79, range 38-876) per case compared with patients having off-pump surgery (median 3, range 0-18). No clinically detectable neurological deficits were seen in either group. Beating heart surgery is associated with fewer emboli than coronary surgery with cardiopulmonary bypass. Further research is necessary to determine whether a smaller number of emboli alters the incidence of neurological deficit after cardiac surgery. PMID:10844840

  12. In vitro verification of multiple-receiver Doppler ultrasound for velocity estimation improvement.

    PubMed

    Hallac, Rami R; Agarwal, Mangilal; Jones, Steven A

    2010-06-01

    The coherent scattering effect, which introduces noise in Doppler-derived velocity estimates, is caused by constructive and destructive interference of sound waves scattered from multiple particles. Because the phase relationship between signals scattered from different particles depends on the orientation of the receiver, the error in a given velocity estimate depends on the receiver location. To examine this dependence, the velocity of a steady uniform flow was measured simultaneously with a transceiver and three receivers, and the cross-correlation coefficients between velocity estimates for pairs of crystals were calculated. The velocity estimates were nearly independent, with cross-correlation coefficients of approximately 0.2. This result agrees with our previously published numerical simulation studies which demonstrated that the coherent scattering noise in receivers separated by 5 degrees or more was nearly uncorrelated. Consequently, the contribution of coherent scattering noise can be reduced by averaging out noise in signals obtained from multiple receivers.

  13. 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.

  14. Renal length discrepancy by ultrasound is a reliable predictor of an abnormal DMSA scan in children.

    PubMed

    Khazaei, Mahmood R; Mackie, Fiona; Rosenberg, Andrew R; Kainer, Gad

    2008-01-01

    A renal length discrepancy (RLD) of more than 10 mm by ultrasound (US) is accepted as a potential indicator of an underlying renal pathology; however, there are few supporting data for this in children. Our objective was to determine a cutoff at which RLD on US is a reliable predictor of dimercaptosuccinate acid (DMSA) scan abnormality. We present data from 90 patients who had both renal US and a DMSA scan, as well as DMSA scan results compared with bipolar RLD by US. Positive (PPV) and negative (NPV) predictive values were calculated for renal RLD from 6 to >10 mm. The left kidney was longer in 56%, whereas the right kidney was longer in 37%; their lengths were equal in 8%. For children at all ages, a left kidney longer than the right by >or=10 mm or a right kidney longer than the left by >or=7 mm gave a PPV for DMSA abnormality of 79% and 100%, respectively. In children older than 4 years, if the right kidney was longer by >or=7 mm or if the left kidney was longer by >or=10 mm, the PPVs for DMSA abnormality were 100% and 63%, respectively. In children younger than 4 years, when the right kidney was longer by >or=6 mm or the left was kidney longer by >or=10 mm, the PPV were 86% and 100%, respectively. Thus, children with a right kidney longer than the left by even <10 mm is a reliable predictor of an abnormal DMSA scan.

  15. Prostate Ultrasound

    MedlinePlus

    ... waves. Ultrasound imaging, also called ultrasound scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ...

  16. Ultrasound -- Pelvis

    MedlinePlus

    ... waves. Ultrasound imaging, also called ultrasound scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ...

  17. Hip Ultrasound

    MedlinePlus

    ... waves. Ultrasound imaging, also called ultrasound scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ...

  18. Ultrasound -- Vascular

    MedlinePlus

    ... waves. Ultrasound imaging, also called ultrasound scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ...

  19. Musculoskeletal Ultrasound

    MedlinePlus

    ... waves. Ultrasound imaging, also called ultrasound scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ...

  20. Ultrasound - Scrotum

    MedlinePlus

    ... waves. Ultrasound imaging, also called ultrasound scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ...

  1. Guided-wave-based damage detection in a composite T-joint using 3D scanning laser Doppler vibrometer

    NASA Astrophysics Data System (ADS)

    Kolappan Geetha, Ganesh; Roy Mahapatra, D.; Srinivasan, Gopalakrishnan

    2012-04-01

    Composite T-joints are commonly used in modern composite airframe, pressure vessels and piping structures, mainly to increase the bending strength of the joint and prevents buckling of plates and shells, and in multi-cell thin-walled structures. Here we report a detailed study on the propagation of guided ultrasonic wave modes in a composite T-joint and their interactions with delamination in the co-cured co-bonded flange. A well designed guiding path is employed wherein the waves undergo a two step mode conversion process, one is due to the web and joint filler on the back face of the flange and the other is due to the delamination edges close to underneath the accessible surface of the flange. A 3D Laser Doppler Vibrometer is used to obtain the three components of surface displacements/velocities of the accessible face of the flange of the T-joint. The waves are launched by a piezo ceramic wafer bonded on to the back surface of the flange. What is novel in the proposed method is that the location of any change in material/geometric properties can be traced by computing a frequency domain power flow along a scan line. The scan line can be chosen over a grid either during scan or during post-processing of the scan data off-line. The proposed technique eliminates the necessity of baseline data and disassembly of structure for structural interrogation.

  2. Characterization of intraventricular flow patterns in healthy neonates from conventional color-Doppler ultrasound

    NASA Astrophysics Data System (ADS)

    Tejman-Yarden, Shai; Rzasa, Callie; Benito, Yolanda; Alhama, Marta; Leone, Tina; Yotti, Raquel; Bermejo, Javier; Printz, Beth; Del Alamo, Juan C.

    2012-11-01

    Left ventricular vortices have been difficult to visualize in the clinical setting due to the lack of quantitative non-invasive modalities, and this limitation is especially important in pediatrics. We have developed and validated a new technique to reconstruct two-dimensional time-resolved velocity fields in the LV from conventional transthoracic color-Doppler images. This non-invasive modality was used to image LV flow in 10 healthy full-term neonates, ages 24-48 hours. Our results show that, in neonates, a diastolic vortex developed during LV filling, was maintained during isovolumic contraction, and decayed during the ejection period. The vortex was created near the base of the ventricle, moved toward the apex, and then back toward the base and LVOT during ejection. In conclusion, we have characterized for the first time the properties of the LV filling vortex in normal neonates, demonstrating that this vortex channels blood from the inflow to the outflow tract of the LV. Together with existing data from adults, our results confirm that the LV vortex is conserved through adulthood. Funded by NIH Grant R21HL108268.

  3. Inverse Problem for Color Doppler Ultrasound-Assisted Intracardiac Blood Flow Imaging

    PubMed Central

    Jang, Jaeseong

    2016-01-01

    For the assessment of the left ventricle (LV), echocardiography has been widely used to visualize and quantify geometrical variations of LV. However, echocardiographic image itself is not sufficient to describe a swirling pattern which is a characteristic blood flow pattern inside LV without any treatment on the image. We propose a mathematical framework based on an inverse problem for three-dimensional (3D) LV blood flow reconstruction. The reconstruction model combines the incompressible Navier-Stokes equations with one-direction velocity component of the synthetic flow data (or color Doppler data) from the forward simulation (or measurement). Moreover, time-varying LV boundaries are extracted from the intensity data to determine boundary conditions of the reconstruction model. Forward simulations of intracardiac blood flow are performed using a fluid-structure interaction model in order to obtain synthetic flow data. The proposed model significantly reduces the local and global errors of the reconstructed flow fields. We demonstrate the feasibility and potential usefulness of the proposed reconstruction model in predicting dynamic swirling patterns inside the LV over a cardiac cycle. PMID:27313657

  4. Inverse Problem for Color Doppler Ultrasound-Assisted Intracardiac Blood Flow Imaging.

    PubMed

    Jang, Jaeseong; Ahn, Chi Young; Choi, Jung-Il; Seo, Jin Keun

    2016-01-01

    For the assessment of the left ventricle (LV), echocardiography has been widely used to visualize and quantify geometrical variations of LV. However, echocardiographic image itself is not sufficient to describe a swirling pattern which is a characteristic blood flow pattern inside LV without any treatment on the image. We propose a mathematical framework based on an inverse problem for three-dimensional (3D) LV blood flow reconstruction. The reconstruction model combines the incompressible Navier-Stokes equations with one-direction velocity component of the synthetic flow data (or color Doppler data) from the forward simulation (or measurement). Moreover, time-varying LV boundaries are extracted from the intensity data to determine boundary conditions of the reconstruction model. Forward simulations of intracardiac blood flow are performed using a fluid-structure interaction model in order to obtain synthetic flow data. The proposed model significantly reduces the local and global errors of the reconstructed flow fields. We demonstrate the feasibility and potential usefulness of the proposed reconstruction model in predicting dynamic swirling patterns inside the LV over a cardiac cycle. PMID:27313657

  5. Use of Transcranial Doppler Ultrasound for Diagnosis of Brain Death in Patients with Severe Cerebral Injury

    PubMed Central

    Li, Yuequn; Liu, Shangwei; Xun, Fangfang; Liu, Zhan; Huang, Xiuying

    2016-01-01

    Background The aim of this study was to investigate the use of transcranial Doppler (TCD) for diagnosis of brain death in patients with severe cerebral injury. Material/Methods This retrospective study enrolled 42 patients based on inclusion and exclusion criteria. All patients were divided into either the brain death group or the survival group according to prognosis. Blood flow of the brain was examined by TCD and analyzed for spectrum changes. The average blood flow velocity (Vm), pulse index (PI), and diastolic blood flow in reverse (RDF) were recorded and compared. Results The data demonstrated that the average speed of bilateral middle cerebral artery blood flow in the brain death group was significantly reduced (P<0.05). However, the PI of the brain death group increased significantly. Moreover, RDF spectrum and nail-like sharp peak spectrum of the brain death group was higher than in the survival group. Conclusions Due to its simplicity, high repeatability, and specificity, TCD combined with other methods is highly valuable for diagnosis of brain death in patients with severe brain injury. PMID:27264088

  6. High-frequency ultrasound as an option for scanning of prepared teeth: an in vitro study.

    PubMed

    Chuembou Pekam, Fabrice; Marotti, Juliana; Wolfart, Stefan; Tinschert, Joachim; Radermacher, Klaus; Heger, Stefan

    2015-01-01

    Because of its ability to non-invasively capture hard structures behind soft tissue, high-frequency ultrasound (HFUS)-assisted microscanning could be a patient-friendly and promising alternative for digitization of prepared teeth. However, intra-oral HFUS microscanners for taking digital impressions of prepared teeth are still not available in the clinical setting. Because working range, scanner size, scanning time, surface reconstruction accuracy and costs are major factors in such a system, our overall objective is to minimize hardware efforts and costs while maintaining the accuracy of the surface-reconstructed tooth model in the range 50 μm. In the work described here, we investigated the accuracy of tooth impression taking using a single-element HFUS microscanner with only three translational degrees of freedom under the restriction that only one occlusal scan is performed per tooth. As in favor of time and scanning efforts the data density is expected to be low, the surface reconstruction process is linked to a model-based surface reconstruction approach using a thin spline robust point matching algorithm to fill data gaps. A priori knowledge for the model is generated based on the original HFUS measurement data. Three artificial teeth and one human molar were prepared and scanned using an extra-oral HFUS laboratory microscanner that was built to test and evaluate different scanning setups. A scanner with three translational degrees of freedom was used to scan the teeth from an occlusal direction. After application of the proposed thin-spline robust point matching algorithm-based reconstruction approach, reconstruction accuracy was assessed by comparing the casts with a control group scanned with an extra-oral laser-scanning system. The mean difference between the reconstructed casts and the optical control group was in the range 14-53 μm. The standard deviation was between 21 and 52 μm. This let us assume that the suggested approach can help to decrease

  7. Discrimination between Newly Formed and Aged Thrombi Using Empirical Mode Decomposition of Ultrasound B-Scan Image

    PubMed Central

    2015-01-01

    Ultrasound imaging is a first-line diagnostic method for screening the thrombus. During thrombus aging, the proportion of red blood cells (RBCs) in the thrombus decreases and therefore the signal intensity of B-scan can be used to detect the thrombus age. To avoid the effect of system gain on the measurements, this study proposed using the empirical mode decomposition (EMD) of ultrasound image as a strategy to classify newly formed and aged thrombi. Porcine blood samples were used for the in vitro induction of fresh and aged thrombi (at hematocrits of 40%). Each thrombus was imaged using an ultrasound scanner at different gains (15, 20, and 30 dB). Then, EMD of ultrasound signals was performed to obtain the first and second intrinsic mode functions (IMFs), which were further used to calculate the IMF-based echogenicity ratio (IER). The results showed that the performance of using signal amplitude of B-scan to reflect the thrombus age depends on gain. However, the IER is less affected by the gain in discriminating between fresh and aged thrombi. In the future, ultrasound B-scan combined with the EMD may be used to identify the thrombus age for the establishment of thrombolytic treatment planning. PMID:25695073

  8. Underwater Acoustic Wavefront Visualization by Scanning Laser Doppler Vibrometer for the Characterization of Focused Ultrasonic Transducers

    PubMed Central

    Longo, Roberto; Vanlanduit, Steve; Arroud, Galid; Guillaume, Patrick

    2015-01-01

    The analysis of acoustic wave fields is important for a large number of engineering designs, communication and health-related reasons. The visualization of wavefronts gives valuable information about the type of transducers and excitation signals more suitable for the test itself. This article is dedicated to the development of a fast procedure for acoustic fields visualization in underwater conditions, by means of laser Doppler vibrometer measurements. The ultrasonic probe is a focused transducer excited by a chirp signal. The scope of this work is to evaluate experimentally the properties of the sound beam in order to get reliable information about the transducer itself to be used in many kinds of engineering tests and transducer design. PMID:26287197

  9. Underwater Acoustic Wavefront Visualization by Scanning Laser Doppler Vibrometer for the Characterization of Focused Ultrasonic Transducers.

    PubMed

    Longo, Roberto; Vanlanduit, Steve; Arroud, Galid; Guillaume, Patrick

    2015-08-13

    The analysis of acoustic wave fields is important for a large number of engineering designs, communication and health-related reasons. The visualization of wavefronts gives valuable information about the type of transducers and excitation signals more suitable for the test itself. This article is dedicated to the development of a fast procedure for acoustic fields visualization in underwater conditions, by means of laser Doppler vibrometer measurements. The ultrasonic probe is a focused transducer excited by a chirp signal. The scope of this work is to evaluate experimentally the properties of the sound beam in order to get reliable information about the transducer itself to be used in many kinds of engineering tests and transducer design.

  10. Detection and localization of rib detachment in thin metal and composite plates by inversion of laser Doppler vibrometry scans.

    PubMed

    Romano, Anthony J; Bucaro, Joseph A; Vignola, Joseph F; Abraham, Phillip B

    2007-05-01

    The laboratory implementation of a fault detection and localization method based on inversion of dynamic surface displacements measured by a scanned laser Doppler vibrometer (SLDV) was investigated. The technique uses flexural wave and generalized force inversion algorithms which have previously been demonstrated using simulated noise-free vibration data generated for thick plates with a finite element model. Here these inversion algorithms to SLDV measurements made in the laboratory on a thin nickel plate and a thin carbon fiber composite plate, both having attached reinforcing ribs with intentional de-bonding of the rib/plate interface at a specific location on each structure are applied. The inverted displacement maps clearly detect and locate the detachment, whereas direct observation of the surface displacements does not. It is shown that the technique is relatively robust to the choice of frequency and to the presence of noise.

  11. Investigation of contact acoustic nonlinearity in delaminations by shearographic imaging, laser doppler vibrometric scanning and finite difference modeling.

    PubMed

    Sarens, Bart; Verstraeten, Bert; Glorieux, Christ; Kalogiannakis, Georgios; Van Hemelrijck, Danny

    2010-06-01

    Full-field dynamic shearography and laser Doppler vibrometric scanning are used to investigate the local contact acoustic nonlinear generation of delamination-induced effects on the vibration of a harmonically excited composite plate containing an artificial defect. Nonlinear elastic behavior caused by the stress-dependent boundary conditions at the delamination interfaces of a circular defect is also simulated by a 3-D second-order, finite-difference, staggered-grid model (displacement-stress formulation). Both the experimental and simulated data reveal an asymmetric motion of the layer above the delamination, which acts as a membrane vibrating with enhanced displacement amplitude around a finite offset displacement. The spectrum of the membrane motion is enriched with clapping-induced harmonics of the excitation frequency. In case of a sufficiently thin and soft membrane, the simulations reveal clear modal behavior at sub-harmonic frequencies caused by inelastic clapping. PMID:20529713

  12. Mode shape reconstruction of an impulse excited structure using continuous scanning laser Doppler vibrometer and empirical mode decomposition.

    PubMed

    Kyong, Yongsoo; Kim, Daesung; Dayou, Jedol; Park, Kyihwan; Wang, Semyung

    2008-07-01

    For vibration testing, discrete types of scanning laser Doppler vibrometer (SLDV) have been developed and have proven to be very useful. For complex structures, however, SLDV takes considerable time to scan the surface of structures and require large amounts of data storage. To overcome these problems, a continuous scan was introduced as an alternative. In this continuous method, the Chebyshev demodulation (or polynomial) technique and the Hilbert transform approach have been used for mode shape reconstruction with harmonic excitation. As an alternative, in this paper, the Hilbert-Huang transform approach is applied to impact excitation cases in terms of a numerical approach, where the vibration of the tested structure is modeled using impulse response functions. In order to verify this technique, a clamped-clamped beam was chosen as the test rig in the numerical simulation and real experiment. This paper shows that with additional innovative steps of using ideal bandpass filters and nodal point determination in the postprocessing, the Hilbert-Huang transformation can be used to create a better mode shape reconstruction even in the impact excitation case.

  13. Peak Systolic Velocity Measurements with Transcranial Doppler Ultrasound Is a Predictor of Incident Stroke among the General Population in China

    PubMed Central

    Wang, Hai-Bo; Laskowitz, Daniel T.; Dodds, Jodi A.; Xie, Gao-Qiang; Zhang, Pu-Hong; Huang, Yi-Ning; Wang, Bo; Wu, Yang-Feng

    2016-01-01

    Background and Objective It is necessary to develop an effective and low-cost screening tool for identifying Chinese people at high risk of stroke. Transcranial Doppler ultrasound (TCD) is a powerful predictor of stroke in the pediatric sickle cell disease population, as demonstrated in the STOP trial. Our study was conducted to determine the prediction value of peak systolic velocities as measured by TCD on subsequent stroke risk in a prospective cohort of the general population from Beijing, China. Methods In 2002, a prospective cohort study was conducted among 1392 residents from 11 villages of the Shijingshan district of Beijing, China. The cohort was scheduled for follow up with regard to incident stroke in 2005, 2007, and 2012 by a study team comprised of epidemiologists, nurses, and physicians. Univariate and multivariate Cox proportional hazard regression models were used to determine the factors associated with incident stroke. Results Participants identified by TCD criteria as having intracranial stenosis had a 3.6-fold greater risk of incident stroke (hazard ratio (HR) 3.57, 95% confidence interval (CI) 1.86–6.83, P<0.01) than those without TCD evidence of intracranial stenosis. The association remained significant in multivariate analysis (HR 2.53, 95% CI 1.31–4.87) after adjusting for other risk factors or confounders. Older age, cigarette smoking, hypertension, and diabetes mellitus remained statistically significant as risk factors after controlling for other factors. Conclusions The study confirmed the screening value of TCD among the general population in urban China. Increasing the availability of TCD screening may help identify subjects as higher risk for stroke. PMID:27513983

  14. Thoracic ultrasound for pleural effusion: delays and cost associated with departmental scanning.

    PubMed

    Bateman, K; Downey, D G; Teare, T

    2010-04-01

    Pleural effusion is a common clinical condition on medical wards and the majority of cases undergo pleural aspiration or chest drain insertion as a diagnostic or therapeutic procedure. The use of a thoracic ultrasound scan (USS) improves diagnostic yield for pleural fluid aspiration and reduces complications and USS is increasingly recommended prior to all pleural aspirations or drains and 'real time' scanning which, as well as potentially reducing delays, enhances the safety of the procedure. In many U.K hospitals a thoracic USS is still routinely performed in the radiology department. We reviewed radiology records and case notes from hospital in-patients to assess potential delays and associated costs with departmental thoracic USS and to identify cases where physician-led portable USS would potentially have improved the patient's journey. We demonstrated delays resulting in significant financial costs to the hospital of an estimated pound17, 880 per annum. However, the cost to the patient is also significant, both in terms of patient experience (many of whom will have an underlying diagnosis of metastatic carcinoma and with a limited life expectancy) but also patient safety. Respiratory physicians are increasingly recognising the importance of portable thoracic USS to guide pleural procedures and there has been increasing use of physician-led portable thoracic USS. Hospitals should be encouraged to fund both portable thoracic USS equipment but it is also crucial that training in this area is properly supported. PMID:20097552

  15. 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.

  16. Neutral thermospheric dynamics observed with two scanning Doppler imagers: 1. Monostatic and bistatic winds

    NASA Astrophysics Data System (ADS)

    Anderson, C.; Conde, M.; McHarg, M. G.

    2012-03-01

    Doppler-shift measurements of the thermospheric 630.0 nm emission recorded by two spatially separated imaging Fabry-Perot spectrometers in Alaska have been combined to infer F region horizontal wind vectors at approximately 75 locations across their overlapping fields-of-view. These “bistatic” horizontal wind estimates rely only on an assumption regarding the local vertical wind (and assume a common observing volume), and thus represent a more direct measurement of the wind than do the monostatic (single-station) vector wind fields routinely inferred by these instruments. Here we present comparisons between both the independently derived monostatic wind fields from each instrument and the bistatic wind estimates inferred in their common observing volumes. Data are presented from observations on three nights during 2010. Two principal findings have emerged from this study. First, the monostatic technique was found to be capable of estimating the actual large-scale wind field reliably under a large range of geophysical conditions, and is well suited to applications requiring only a large-scale, ‘big picture’ approximation of the wind flow. Secondly, the bistatic (or tristatic) technique is essential for applications requiring detailed knowledge of the small-scale behavior of the wind, as for example is required when searching for gravity waves.

  17. 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.

  18. Gastroepiploic artery as an in situ coronary artery bypass graft: evaluation of MRI and colour Doppler ultrasound in follow-up.

    PubMed

    Vanninen, R L; Vainio, P A; Manninen, H I; Suhonen, M; Jaakola, P

    1995-01-01

    The right gastroepiploic artery, increasingly used as an in situ coronary artery bypass graft, has good long-term patency. This study aimed to assess the accuracy and limitations of magnetic resonance imaging (MRI) and colour Doppler ultrasound (US) in postoperative follow-up of such cases. In eight consecutive patients (6 men, 2 women, mean age 57 years), conventional angiography, MRI and US were performed to evaluate graft patency. Colour Doppler US, performed within a week of the operation, correctly detected flow in three patent grafts. MRI (1.5 tesla) was performed c. 17 months after surgery, using a spine coil and a coronal two-dimensional Flash-type imaging sequence. At angiography six of the eight gastroepiploic artery grafts were patent, and two were occluded. The sensitivity and specificity of MRI were 100%. This accuracy makes MRI a promising method for noninvasive post-operative evaluation of right gastroepiploic artery graft patency. PMID:7644909

  19. Multiparametric sonographic imaging of a capillary hemangioma of the testis: appearances on gray-scale, color Doppler, contrast-enhanced ultrasound and strain elastography.

    PubMed

    Bernardo, Silvia; Konstantatou, Eleni; Huang, Dean Y; Deganello, Annamaria; Philippidou, Marianna; Brown, Christian; Sellars, Maria E; Sidhu, Paul S

    2016-03-01

    We report a case of a lobular capillary hemangioma in a 66-year-old man, who presented with left testicular pain, with an asymptomatic incidental right testicular lesion found on ultrasonography. The sonographic examination demonstrated a heterogeneous mainly iso-echoic intratesticular lesion with marked vascularity on the color Doppler examination. Further evaluation with contrast-enhanced ultrasound and strain elastography was performed; the multiparametric imaging suggested a benign tumor. The multidisciplinary team decision with patient consent was to perform a radical orchiectomy with subsequent histopathology confirming a benign lobular capillary hemangioma.

  20. Ultrasound Annual, 1984

    SciTech Connect

    Sanders, R.C.; Hill, M.C.

    1984-01-01

    The 1984 edition of Ultrasound Annual explores new applications of ultrasound in speech and swallowing and offers guidelines on the use of ultrasound and nuclear medicine in thyroid and biliary tract disease. Other areas covered include Doppler sonography of the abdomen, intraoperative abdominal ultrasound, sonography of the placenta, ultrasound of the neonatal head and abdomen, and sonographic echo patterns created by fat.

  1. Comparison of the biometric formulas used for applanation A-scan ultrasound biometry.

    PubMed

    Özcura, Fatih; Aktaş, Serdar; Sağdık, Hacı Murat; Tetikoğlu, Mehmet

    2016-10-01

    The purpose of the study was to compare the accuracy of various biometric formulas for predicting postoperative refraction determined using applanation A-scan ultrasound. This retrospective comparative study included 485 eyes that underwent uneventful phacoemulsification with intraocular lens (IOL) implantation. Applanation A-scan ultrasound biometry and postoperative manifest refraction were obtained in all eyes. Biometric data were entered into each of the five IOL power calculation formulas: SRK-II, SRK/T, Holladay I, Hoffer Q, and Binkhorst II. All eyes were divided into three groups according to axial length: short (≤22.0 mm), average (22.0-25.0 mm), and long (≥25.0 mm) eyes. The postoperative spherical equivalent was calculated and compared with the predicted refractive error using each biometric formula. The results showed that all formulas had significantly lower mean absolute error (MAE) in comparison with Binkhorst II formula (P < 0.01). The lowest MAE was obtained with the SRK-II for average (0.49 ± 0.40 D) and short (0.67 ± 0.54 D) eyes and the SRK/T for long (0.61 ± 0.50 D) eyes. The highest postoperative hyperopic shift was seen with the SRK-II for average (46.8 %), short (28.1 %), and long (48.4 %) eyes. The highest postoperative myopic shift was seen with the Holladay I for average (66.4 %) and long (71.0 %) eyes and the SRK/T for short eyes (80.6 %). In conclusion, the SRK-II formula produced the lowest MAE in average and short eyes and the SRK/T formula produced the lowest MAE in long eyes. The SRK-II has the highest postoperative hyperopic shift in all eyes. The highest postoperative myopic shift is with the Holladay I for average and long eyes and SRK/T for short eyes.

  2. Seminal, clinical and colour-Doppler ultrasound correlations of prostatitis-like symptoms in males of infertile couples.

    PubMed

    Lotti, F; Corona, G; Mondaini, N; Maseroli, E; Rossi, M; Filimberti, E; Noci, I; Forti, G; Maggi, M

    2014-01-01

    'Prostatitis-like symptoms' (PLS) are a cluster of bothersome conditions defined as 'perineal and/or ejaculatory pain or discomfort and National Institutes of Health-Chronic Prostatitis Symptom Index (NIH-CPSI) pain subdomain score ≥4' (Nickel's criteria). PLS may originate from the prostate or from other portions of the male genital tract. Although PLS could be associated with 'prostatitis', they should not be confused. The NIH-CPSI is considered the gold-standard for assessing PLS severity. Although previous studies investigated the impact of prostatitis, vesiculitis or epididymitis on semen parameters, correlations between their related symptoms and seminal or scrotal/transrectal colour-Doppler ultrasound (CDU) characteristics have not been carefully determined. And no previous study evaluated the CDU features of PLS in infertile men. This study was aimed at investigating possible associations among NIH-CPSI (total and subdomain) scores and PLS, with seminal, clinical and scrotal/transrectal CDU parameters in a cohort of males of infertile couples. PLS of 400 men (35.8 ± 7.2 years) with a suspected male factor were assessed by the NIH-CPSI. All patients underwent, during the same day, semen analysis, seminal plasma interleukin 8 (sIL-8, a marker of male genital tract inflammation), biochemical evaluation, urine/seminal cultures, scrotal/transrectal CDU. PLS was detected in 39 (9.8%) subjects. After adjusting for age, waist and total testosterone (TT), no association among NIH-CPSI (total or subdomain) scores or PLS and sperm parameters was observed. However, we found a positive association with current positive urine and/or seminal cultures, sIL-8 levels and CDU features suggestive of inflammation of the epididymis, seminal vesicles, prostate, but not of the testis. The aforementioned significant associations of PLS were further confirmed by comparing PLS patients with age-, waist- and TT-matched PLS-free patients (1 : 3 ratio). In conclusion, NIH

  3. 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.

  4. Scanning ultrasound removes amyloid-β and restores memory in an Alzheimer's disease mouse model.

    PubMed

    Leinenga, Gerhard; Götz, Jürgen

    2015-03-11

    Amyloid-β (Aβ) peptide has been implicated in the pathogenesis of Alzheimer's disease (AD). We present a nonpharmacological approach for removing Aβ and restoring memory function in a mouse model of AD in which Aβ is deposited in the brain. We used repeated scanning ultrasound (SUS) treatments of the mouse brain to remove Aβ, without the need for any additional therapeutic agent such as anti-Aβ antibody. Spinning disk confocal microscopy and high-resolution three-dimensional reconstruction revealed extensive internalization of Aβ into the lysosomes of activated microglia in mouse brains subjected to SUS, with no concomitant increase observed in the number of microglia. Plaque burden was reduced in SUS-treated AD mice compared to sham-treated animals, and cleared plaques were observed in 75% of SUS-treated mice. Treated AD mice also displayed improved performance on three memory tasks: the Y-maze, the novel object recognition test, and the active place avoidance task. Our findings suggest that repeated SUS is useful for removing Aβ in the mouse brain without causing overt damage, and should be explored further as a noninvasive method with therapeutic potential in AD. PMID:25761889

  5. Scanning ultrasound removes amyloid-β and restores memory in an Alzheimer's disease mouse model.

    PubMed

    Leinenga, Gerhard; Götz, Jürgen

    2015-03-11

    Amyloid-β (Aβ) peptide has been implicated in the pathogenesis of Alzheimer's disease (AD). We present a nonpharmacological approach for removing Aβ and restoring memory function in a mouse model of AD in which Aβ is deposited in the brain. We used repeated scanning ultrasound (SUS) treatments of the mouse brain to remove Aβ, without the need for any additional therapeutic agent such as anti-Aβ antibody. Spinning disk confocal microscopy and high-resolution three-dimensional reconstruction revealed extensive internalization of Aβ into the lysosomes of activated microglia in mouse brains subjected to SUS, with no concomitant increase observed in the number of microglia. Plaque burden was reduced in SUS-treated AD mice compared to sham-treated animals, and cleared plaques were observed in 75% of SUS-treated mice. Treated AD mice also displayed improved performance on three memory tasks: the Y-maze, the novel object recognition test, and the active place avoidance task. Our findings suggest that repeated SUS is useful for removing Aβ in the mouse brain without causing overt damage, and should be explored further as a noninvasive method with therapeutic potential in AD.

  6. Impact of nodular size on the predictive values of gray-scale, color-Doppler ultrasound, and sonoelastography for assessment of thyroid nodules

    PubMed Central

    Hong, Yu-rong; Wu, Yu-lian; Luo, Zhi-yan; Wu, Ning-bo; Liu, Xue-ming

    2012-01-01

    Objective: To define the roles of gray-scale, color-Doppler ultrasound, and sonoelastography for the assessment of thyroid nodule to determine whether nodule size affects the differential diagnosis of benign and malignant. Methods: A total of 243 consecutive subjects (214 women, 29 men) with 329 thyroid nodules were examined by gray-scale, color-Doppler ultrasound, and sonoelastography in this prospective study. All patients underwent surgery and the final diagnosis was obtained from histopathological examination. Results: Three hundred and twenty-nine nodules (208 benign, 121 malignant) were divided into small (SNs, 5–10 mm, n=137) and large (LNs, >10 mm, n=192) nodules. Microcalcifications were more frequent in malignant LNs than in malignant SNs, but showed no significant difference between benign LNs and SNs. Poorly-circumscribed margins were not significantly different between malignant SNs and LNs, but were less frequent in benign LNs than in benign SNs. Among all nodules, marked intranodular vascularity was more frequent in LNs than in SNs. By comparison, shape ratio of anteroposterior to transverse dimensions (A/T) ≥1 was less frequent in LNs than in SNs. Otherwise, among all nodules, marked hypoechogenicity and elasticity score of 4–6 showed no significant difference between LNs and SNs. Conclusions: The predictive values of microcalcifications, nodular margins, A/T ratio, and marked intranodular vascularity depend on nodule size, but the predictive values of echogenicity and elastography do not. PMID:22949361

  7. [Evaluation of the diagnostic value of color Doppler ultrasound examination of salivary gland neoplasms and metastatic tumors from the facial bones].

    PubMed

    Falkowski, A

    1998-01-01

    The aim of the study was to evaluate usefulness of colour Doppler ultrasound examination in diagnosing the salivary gland tumours and the metastatic tumours of the neck originating from the facial part of the skull. Epidemiology and histopathology of the neoplasms involving the salivary glands and the facial skeleton were discussed including the route of their spreading to the neck. The author presents update techniques of bony face radiologic imaging and basic principles of modern colour Doppler ultrasound. The examinations with the use of a colour Doppler equipment-Acuson 128-XP 10 were performed in 150 patients with the neck tumours. The exact location, size, morphology and blood supply were assessed using B and B colour mode. Then some big neck vessels like the common, internal and external carotid artery, vertebral artery, internal jugular vein were visualized. All the patients were divided into three groups according to what they were suffering from: sialoadenitis, benign and malignant tumours. The obtained results were compared and confronted with clinical features. The pattern of vascularization failed to allow for establishing preliminary diagnosis in patients in each group. Within the first group, with inflamed glands did not compress the neck vessels. Of all the patients with benign tumours, extrinsic compression on the internal jugular vein and the carotid arteries was found in 16 and 14 patients respectively. In the third group of patients with malignant disease, compression on the veins was detected in 10 cases while 5 tumours compressed the arteries. The invasion involved the internal jugular vein in 7 patients while the common and internal carotid arteries were invaded in 6. The vertebral artery was never found to be affected. It was demonstrated that compression on veins resulted in disturbing the flow which was not observed as far as the arteries were concerned. Disturbing in the flow of veins and arteries was disclosed in cases of invasion

  8. Scanning Laser Doppler Vibrometer Measurements Inside Helicopter Cabins in Running Conditions: Problems and Mock-up Testing

    SciTech Connect

    Revel, G. M.; Castellini, P.; Chiariotti, P.; Tomasini, E. P.; Cenedese, F.; Perazzolo, A.

    2010-05-28

    The present work deals with the analysis of problems and potentials of laser vibrometer measurements inside helicopter cabins in running conditions. The paper describes the results of a systematic measurement campaign performed on an Agusta A109MKII mock-up. The aim is to evaluate the applicability of Scanning Laser Doppler Vibrometer (SLDV) for tests in simulated flying conditions and to understand how performances of the technique are affected when the laser head is placed inside the cabin, thus being subjected to interfering inputs. Firstly a brief description of the performed test cases and the used measuring set-ups are given. Comparative tests between SLDV and accelerometers are presented, analyzing the achievable performances for the specific application. Results obtained measuring with SLDV placed inside the helicopter cabin during operative excitation conditions are compared with those performed with the laser lying outside the mock-up, these last being considered as 'reference measurements'. Finally, in order to give an estimate of the uncertainty level on measured signals, a study linking the admitted percentage of noise content on vibrometer signals due to laser head vibration levels will be introduced.

  9. Are Results of 4-D Ultrasound Angiography Examinations Dependent on the Doppler Technology Applied? Comparison of Results Obtained from an In Vivo Model.

    PubMed

    Kudla, Marek J; Los, Andrzej; Alcazar, Juan Luis

    2016-02-01

    We aimed to evaluate the agreement of results obtained by 4-D spatio-temporal image correlation (STIC) angiography with two options of Doppler technology (power Doppler [PD] and high-definition flow [HDF]) from an ovary as an in vivo model. Thirty-eight ovaries were recorded by trans-vaginal ultrasound examination in the first part of the menstrual cycle. Two STIC sequences (4-D HDF and 4-D PD) were stored. Volumetric pulsatility index, volumetric resistance index and volumetric systolic/diastolic index for each of these sequences were calculated, and their mean values were compared and correlated. Agreement between 4-D HDF and 4-D PD was assessed using the intra-class correlation coefficient. Intra-class correlation coefficients for all three indices were high, but 95% confidence intervals and limits of agreement were wide. We conclude that both 4-D power Doppler and 4-D high-definition flow may be used for calculating volumetric pulsatility index, volumetric resistance index and volumetric systolic/diastolic index from a STIC sequence, at least in ovaries used as an in vivo model. However, values obtained by both methods cannot be used interchangeably.

  10. Can Doppler or contrast-enhanced ultrasound analysis add diagnostically important information about the nature of breast lesions?

    PubMed Central

    Stanzani, Daniela; Chala, Luciano F.; de Barros, Nestor; Cerri, Giovanni G.; Chammas, Maria Cristina

    2014-01-01

    OBJECTIVES: Despite evidence suggesting that Doppler ultrasonography can help to differentiate between benign and malignant breast lesions, it is rarely applied in clinical practice. The aim of this study was to determine whether certain vascular features of breast masses observed by duplex Doppler and color Doppler ultrasonography (before and/or after microbubble contrast injection) add information to the gray-scale analysis and support the Breast Imaging-Reporting and Data System (BI-RADS) classification. METHODS: Seventy solid lesions were prospectively evaluated with gray-scale ultrasonography, color Doppler ultrasonography, and contrast-enhanced ultrasonography. The morphological analysis and lesion vascularity were correlated with the histological results. RESULTS: Percutaneous core biopsies revealed that 25/70 (17.5%) lesions were malignant, while 45 were benign. Hypervascular lesions with tortuous and central vessels, a resistive index (RI)≥0.73 before contrast injection, and an RI≥0.75 after contrast injection were significantly predictive of malignancy (p<0.001). CONCLUSION: The combination of gray-scale ultrasonography data with unenhanced or enhanced duplex Doppler and color Doppler US data can provide diagnostically useful information. These techniques can be easily implemented because Doppler devices are already present in most health centers. PMID:24519198

  11. Mirror artifacts in obstetric ultrasound; case presentation of a ghost twin during the second trimester ultrasound scan

    PubMed Central

    Ahn, Hyunyoung; Hernández-Andrade, Edgar; Romero, Roberto; Patwardhan, Manasi; Goncalves, Luis F.; Aurioles, Alma; Garcia, Maynor; Hassan, Sonia S.; Yeo, Lami

    2014-01-01

    Mirror artifacts are produced by the reflection of ultrasound waves after they propagate through a structure and encounter a strong and smooth interface capable of acting as a mirror. Ultrasound waves bounce back and forth between the mirroring interface and the reflective object and then eventually return to the transducer. The typical display of the mirror artifact consists of two similar structures separated and at a similar distance from the reflective interface. We report a mirror artifact in a patient with a singleton gestation at 18 weeks. The image was interpreted as consistent with a twin gestation using transabdominal and transvaginal ultrasound. The differential diagnosis consisted of an abdominal heterotopic pregnancy. The presence of synchronized but opposite movements of both fetuses, and the blurred image of the second fetus, suggested a mirror artifact. The reflective surface was created by the interface located between a distended recto-sigmoid filled with gas and the posterior uterine wall. Mirror artifacts can lead to diagnostic errors. This case illustrates how a distended recto-sigmoid can generate an image that simulates either a twin gestation or an abdominal heterotopic pregnancy. PMID:24071724

  12. Diagnostic performance of axial-strain sonoelastography in confirming clinically diagnosed Achilles tendinopathy: comparison with B-mode ultrasound and color Doppler imaging.

    PubMed

    Ooi, Chin Chin; Schneider, Michal Elisabeth; Malliaras, Peter; Chadwick, Martine; Connell, David Alister

    2015-01-01

    This primary aim of this study was to evaluate the diagnostic performance of axial-strain sonoelastography (ASE), B-mode ultrasound (US) and color Doppler US in confirming clinically symptomatic Achilles tendinopathy. The secondary aim was to establish the relationship between the strain ratio during sonoelastography and Victorian Institute of Sport Assessment-Achilles (VISA-A) scores. The VISA-A questionnaire is a validated clinical rating scale that evaluates the symptoms and dysfunction of the Achilles tendon. One hundred twenty Achilles tendons of 120 consecutively registered patients with clinical symptoms of Achilles tendinopathy and another 120 gender- and age-matched, asymptomatic Achilles tendons of 120 healthy volunteers were assessed with B-mode US, ASE and color Doppler US. Symptomatic patients had significantly higher strain ratio scores and softer Achilles tendon properties compared with controls (p < 0.001). The strain ratio was moderately correlated with VISA-A scores (r = -0.62, p < 0.001). The diagnostic accuracy of B-mode US, ASE and color Doppler US in confirming clinically symptomatic Achilles tendinopathy was 94.7%, 97.8% and 82.5% respectively. There was excellent correlation between the clinical reference standard and the grade of tendon quality on ASE (κ = 0.91, p < 0.05), compared with B-mode US (κ = 0.74, p < 0.05) and color Doppler imaging (κ = 0.49, p < 0.05). ASE is an accurate clinical tool in the evaluation of Achilles tendinopathy, with results comparable to those of B-mode US and excellent correlation with clinical findings. The strain ratio may offer promise as a supplementary tool for the objective evaluation of Achilles tendon properties.

  13. Thermal therapy for breast tumors by using a cylindrical ultrasound phased array with multifocus pattern scanning: a preliminary numerical study

    NASA Astrophysics Data System (ADS)

    Ho, Cheng-Shiao; Ju, Kuen-Cheng; Cheng, Tze-Yuan; Chen, Yung-Yaw; Lin, Win-Li

    2007-08-01

    The purpose of this study is to investigate the feasibility of using a 1 MHz cylindrical ultrasound phased array with multifocus pattern scanning to produce uniform heating for breast tumor thermal therapy. The breast was submerged in water and surrounded by the cylindrical ultrasound phased array. A multifocus pattern was generated and electrically scanned by the phased array to enlarge the treatment lesion in single heating. To prevent overheating normal tissues, a large planning target volume (PTV) would be divided into several planes with several subunits on each plane and sequentially treated with a cooling phase between two successive heatings of the subunit. Heating results for different target temperatures (Ttgt), blood perfusion rates and sizes of the PTV have been studied. Furthermore, a superficial breast tumor with different water temperatures was also studied. Results indicated that a higher target temperature would produce a slightly larger thermal lesion, and a higher blood perfusion rate would not affect the heating lesion size but increase the heating time significantly. The acoustic power deposition and temperature elevations in ribs can be minimized by orienting the acoustic beam from the ultrasound phased array approximately parallel to the ribs. In addition, a large acoustic window on the convex-shaped breast surface for the proposed ultrasound phased array and the cooling effect of water would prevent the skin overheating for the production of a lesion at any desired location. This study demonstrated that the proposed cylindrical ultrasound phased array can provide effective heating for breast tumor thermal therapy without overheating the skin and ribs within a reasonable treatment time.

  14. Temperature-dependent ultrasound color flow Doppler imaging in the study of a VX2 tumor in rabbits: preliminary findings.

    PubMed

    Shmulewitz, A; Teefey, S A; Coldwell, D; Starr, F L

    1993-01-01

    Neovascularity in a VX2 carcinoma in rabbit liver was detectable, using an ultrasonic color Doppler flow imager. Intraportal infusion of heated saline increased the fractional area of color flow Doppler signals by at least 5% and as much as 30%, within and surrounding the tumors of all six rabbits studied. The effect of the fluid load was an increase in fractional area of color flow Doppler signals by 5 to 20% and was determined by the measurements following infusion and return to baseline temperature. The largest increment in color Doppler signal was observed in peritumoral vessels (10-40%). In contrast, the fractional area of color-coded pixels within the tumor was only slightly higher or lower (5-10%) at the peak temperature than at the baseline measurements. The temperature within the tumors was as much as 1 degree lower than parenchymal tissue in all animals measured. This was presumably due to the portal vein blood supply to normal tissue and predominantly hepatic artery supply to the pathological tissue. High velocities and persistent bidirectional flow were observed within the tumors only at the peak temperatures (> 43.5 degrees C). This experiment suggests that thermal stress may enhance tumor detectability by color Doppler imaging. Further development of a quantitative analysis method for color Doppler studies is needed. PMID:8511828

  15. Usefulness of Routine Head Ultrasound Scans Before Surgery for Congenital Heart Disease

    PubMed Central

    Rios, Danielle R.; Welty, Stephen E.; Gunn, Julia K.; Beca, John; Minard, Charles G.; Goldsworthy, Michelle; Coleman, Lee; Hunter, Jill V.; Andropoulos, Dean B.

    2013-01-01

    OBJECTIVE: The purpose of this study was to assess the utility of preoperative head ultrasound scan (HUS) in a cohort of newborns also undergoing preoperative MRI as part of a prospective research study of brain injury in infants having surgery for congenital heart disease (CHD). METHODS: A total of 167 infants diagnosed with CHD were included in this 3-center study. None of the patients had clinical signs or symptoms of preoperative brain injury, and all patients received both HUS and brain MRI before undergoing surgical intervention. HUS and MRI results were reported by experienced neuroradiologists who were blinded to any specific clinical details of the study participants. The findings of the individual imaging modes were compared to evaluate for the presence of brain injury. RESULTS: Preoperative brain injury was present on HUS in 5 infants (3%) and on MRI in 44 infants (26%) (P < .001). Four of the HUS showed intraventricular hemorrhage not seen on MRI, suggesting false-positive results, and the fifth showed periventricular leukomalacia. The predominant MRI abnormality was white matter injury (n = 32). Other findings included infarct (n = 16) and hemorrhage (n = 5). CONCLUSIONS: Preoperative brain injury on MRI was present in 26% of infants with CHD, but only 3% had any evidence of brain injury on HUS. Among positive HUS, 80% were false-positive results. Our findings suggest that routine HUS is not indicated in asymptomatic term or near-term neonates undergoing surgery for CHD, and MRI may be a preferable tool when the assessment of these infants is warranted. PMID:23690521

  16. 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)

  17. Comparison of Optical and Power Doppler Ultrasound Imaging for Non-Invasive Evaluation of Arsenic Trioxide as a Vascular Disrupting Agent in Tumors

    PubMed Central

    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. PMID:23029403

  18. Ultrasound annual, 1986

    SciTech Connect

    Sanders, R.C.; Hill, M.C.

    1986-01-01

    This book provides an analyses of developments in the field of diagnostic ultrasound. Endoscopic ultrasound and ultrasound-guided aspiration of ovarian follicles for in vitro fertilization are addressed. The use of Doppler ultrasound to measure blood flow in obstetrics is also examined.

  19. Basic Principles of Ultrasound

    NASA Astrophysics Data System (ADS)

    Robinson, Teresa M.

    Ultrasound has been used in medicine for at least 50 years. Its current importance can be judged by the fact that, of all the various kinds of diagnostic images produced in the world, 1 in 4 is an ultrasound scan. Ultrasound energy is exactly like sound energy, it is a variation in the pressure within a medium. The only difference is that the rate of variation of pressure, the frequency of the wave, is too rapid for humans to hear. Medical ultrasound lies within a frequency range of 30 kHz to 500 MHz. Generally, the lower frequencies (30 kHz to 3 MHz) are for therapeutic purposes, the higher ones (2 to 40 MHz) are for diagnosis (imaging and Doppler), the very highest (50 to 500 MHz) are for microscopic images. For diagnostic purposes two main techniques are employed; the pulse-echo method is used to create images of tissue distribution; the Doppler effect is used to assess tissue movement and blood flow.

  20. Bedside Doppler ultrasound for the assessment of renal perfusion in the ICU: advantages and limitations of the available techniques.

    PubMed

    Schnell, David; Darmon, Michael

    2015-12-01

    Three Doppler-derived techniques have been proposed to assess renal perfusion at bedside: Doppler-based renal resistive index (RI) which has been extensively but imperfectly studied in assessing renal allograft status and changes in renal perfusion in critically ill patients and for predicting the reversibility of an acute kidney injury (AKI), semi-quantitative evaluation of renal perfusion using colour-Doppler which may be easier to perform and may give similar information than RI and contrast-enhanced sonography that may allow more precise renal and cortical perfusion assessment. These promising tools have several obvious advantages including their feasibility, non-invasiveness, repeatability and potential interest in assessing renal function or perfusion. However, several limits need to be taken into account with these techniques, and promising results remain associated with large areas of uncertainty. This editorial will describe more carefully advantages and limits of these techniques and will discuss their potential interest in assessing renal perfusion.

  1. Phase-resolved optical coherence tomography and optical Doppler tomography for imaging blood flow in human skin with fast scanning speed and high velocity sensitivity

    SciTech Connect

    Zhao, Yonghua; Chen, Zhongping; Saxer, Christopher; Xiang, Shaohua; Boer, Johannes F. de; Nelson, J. Stuart

    2000-01-15

    We have developed a novel phase-resolved optical coherence tomography (OCT) and optical Doppler tomography (ODT) system that uses phase information derived from a Hilbert transformation to image blood flow in human skin with fast scanning speed and high velocity sensitivity. Using the phase change between sequential scans to construct flow-velocity imaging, this technique decouples spatial resolution and velocity sensitivity in flow images and increases imaging speed by more than 2 orders of magnitude without compromising spatial resolution or velocity sensitivity. The minimum flow velocity that can be detected with an axial-line scanning speed of 400 Hz and an average phase change over eight sequential scans is as low as 10 {mu}m/s , while a spatial resolution of 10 {mu}m is maintained. Using this technique, we present what are to our knowledge the first phase-resolved OCT/ODT images of blood flow in human skin. (c) 2000 Optical Society of America.

  2. The value of serial Doppler ultrasound as a predictor of clinical outcome and the need for transplantation in fulminant and severe acute liver failure.

    PubMed

    Deasy, N P; Wendon, J; Meire, H B; Sidhu, P S

    1999-02-01

    The aim of this study was to document the changes in Doppler ultrasound variables of the hepatic artery and portal vein in fulminant and severe acute liver failure, and to assess their prognostic significance. 18 adult patients with fulminant and severe acute liver failure underwent serial Doppler sonography, in the early stages after presentation. 12 hourly measurements of hepatic artery resistance index (HARI), spleen length, portal vein cross-sectional area, time average velocity (TAV) and flow volume were performed. Mean HARI (p = 0.03) and mean maximum HARI (p = 0.03) were significantly higher in those who fulfilled criteria for liver transplantation. Increased portal vein flow was demonstrated, although the difference between the groups was not significant. A significant increase in portal vein cross-sectional area (p < 0.02) and spleen length (p < 0.02) was demonstrated. In summary, an increase in portal blood flow to the damaged liver has been demonstrated. The mean HARI is significantly higher in patients who fulfil transplant criteria and may possibly be used as an indicator of poorer prognosis and the need for liver transplantation in acute severe and fulminant liver failure.

  3. Ultrasound features of lacrimal gland in Sjogren's syndrome: case report.

    PubMed

    Seceleanu, Andreea; Pop, Sorin; Preda, Dan; Szabo, Ioan; Rogojan, Liliana; Seceleanu, Radu

    2012-12-01

    A case is presented of bilateral lacrimal gland hypertrophy with secondary glaucoma due to the increased episcleralvenous pressure. Diagnostic work-up included clinical methods associated with ultrasound (A- and B-scan, Doppler ultrasound) and magnetic resonance imaging techniques. Clinical data revealed proptosis, episcleral congestion, and elevated intraocular pressure. Abnormal Schirmer's test and xerophthalmia were also present. Ultrasound examination identified enlarged masses of a cystic structure in lacrimal fossae bilaterally, superotemporally to the globe, more pronounced on the left side. Doppler ultrasound revealed vascularization and magnetic resonance imaging completed the findings offered by ultrasound methods. Based on the clinical aspect and the possible visual impairment due to secondary glaucoma, the mass lesion on the left side was removed by neurosurgical approach. Histopathology confirmed destruction of the lacrimal gland and immunohistochemistry indicated Sjogren's syndrome lesions. Sonography is able to provide noninvasively much of the information needed by the clinician. The A-scan and B-scan ultrasound techniques and color Doppler allow tracking and discrimination of orbital diseases, such as lacrimal gland lesions. Associated with clinical features, these methods provide the basis of correct diagnosis and appropriate therapy for lacrimal gland pathology.

  4. A wall-less poly(vinyl alcohol) cryogel flow phantom with accurate scattering properties for transcranial Doppler ultrasound propagation channels analysis.

    PubMed

    Weir, Alexander J; Sayer, Robin; Cheng-Xiang Wang; Parks, Stuart

    2015-08-01

    Medical phantoms are frequently required to verify image and signal processing systems, and are often used to support algorithm development for a wide range of imaging and blood flow assessments. A phantom with accurate scattering properties is a crucial requirement when assessing the effects of multi-path propagation channels during the development of complex signal processing techniques for Transcranial Doppler (TCD) ultrasound. The simulation of physiological blood flow in a phantom with tissue and blood equivalence can be achieved using a variety of techniques. In this paper, poly (vinyl alcohol) cryogel (PVA-C) tissue mimicking material (TMM) is evaluated in conjunction with a number of potential scattering agents. The acoustic properties of the TMMs are assessed and an acoustic velocity of 1524ms(-1), an attenuation coefficient of (0:49) × 10(-4)fdBm(1)Hz(-1), a characteristic impedance of (1.72) × 10(6)Kgm(-2)s(-1) and a backscatter coefficient of (1.12) × 10(-28)f(4)m(-1)Hz(-4)sr(-1) were achieved using 4 freeze-thaw cycles and an aluminium oxide (Al(2)O(3)) scattering agent. This TMM was used to make an anatomically realistic wall-less flow phantom for studying the effects of multipath propagation in TCD ultrasound.

  5. Cardiac-Gated En Face Doppler Measurement of Retinal Blood Flow Using Swept-Source Optical Coherence Tomography at 100,000 Axial Scans per Second

    PubMed Central

    Lee, ByungKun; Choi, WooJhon; Liu, Jonathan J.; Lu, Chen D.; Schuman, Joel S.; Wollstein, Gadi; Duker, Jay S.; Waheed, Nadia K.; Fujimoto, James G.

    2015-01-01

    Purpose. To develop and demonstrate a cardiac gating method for repeatable in vivo measurement of total retinal blood flow (TRBF) in humans using en face Doppler optical coherence tomography (OCT) at commercially available imaging speeds. Methods. A prototype swept-source OCT system operating at 100-kHz axial scan rate was developed and interfaced with a pulse oximeter. Using the plethysmogram measured from the earlobe, Doppler OCT imaging of a 1.5- × 2-mm area at the optic disc at 1.8 volumes/s was synchronized to cardiac cycle to improve sampling of pulsatile blood flow. Postprocessing algorithms were developed to achieve fully automatic calculation of TRBF. We evaluated the repeatability of en face Doppler OCT measurement of TRBF in 10 healthy young subjects using three methods: measurement at 100 kHz with asynchronous acquisition, measurement at 100 kHz with cardiac-gated acquisition, and a control measurement using a 400-kHz instrument with asynchronous acquisition. Results. The median intrasubject coefficients of variation (COV) of the three methods were 8.0%, 4.9%, and 6.1%, respectively. All three methods correlated well, without a significant bias. Mean TRBF measured at 100 kHz with cardiac-gated acquisition was 40.5 ± 8.2 μL/min, and the range was from 26.6 to 55.8 μL/min. Conclusions. Cardiac-gated en face Doppler OCT can achieve smaller measurement variability than previously reported methods. Although further validation in older subjects and diseased subjects is required, precise measurement of TRBF using cardiac-gated en face Doppler OCT at commercially available imaging speeds should be feasible. PMID:25744974

  6. Model based assessment of vestibular jawbone thickness using high frequency 3D ultrasound micro-scanning

    NASA Astrophysics Data System (ADS)

    Habor, Daniel; Neuhaus, Sarah; Vollborn, Thorsten; Wolfart, Stefan; Radermacher, Klaus; Heger, Stefan

    2013-03-01

    Endosseous implants are well-established in modern dentistry. However, without appropriate therapeutic intervention, progressive peri-implant bone loss may lead to failing implants. Conventionally, the particularly relevant vestibular jawbone thickness is monitored using radiographic 3D imaging methods. Ionizing radiation, as well as imaging artifacts caused by metallic implants and superstructures are major drawbacks of these imaging modalities. In this study, a high frequency ultrasound (HFUS) based approach to assess the vestibular jawbone thickness is being introduced. It should be emphasized that the presented method does not require ultrasound penetration of the jawbone. An in-vitro study using two porcine specimens with inserted endosseous implants has been carried out to assess the accuracy of our approach. The implant of the first specimen was equipped with a gingiva former while a polymer superstructure was mounted onto the implant of the second specimen. Ultrasound data has been acquired using a 4 degree of freedom (DOF) high frequency (<50MHz) laboratory ultrasound scanner. The ultrasound raw data has been converted to polygon meshes including the surfaces of bone, gingiva, gingiva former (first specimen) and superstructure (second specimen). The meshes are matched with a-priori acquired 3D models of the implant, the superstructure and the gingiva former using a best-fit algorithm. Finally, the vestibular peri-implant bone thickness has been assessed in the resulting 3D models. The accuracy of this approach has been evaluated by comparing the ultrasound based thickness measurement with a reference measurement acquired with an optical extra-oral 3D scanner prior to covering the specimens with gingiva. As a final result, the bone thicknesses of the two specimens were measured yielding an error of -46+/-89μm (first specimen) and 70+/-93μm (second specimen).

  7. Ultrasound scanning of the pelvis and abdomen for staging of gynecological tumors: a review.

    PubMed

    Fischerova, D

    2011-09-01

    This Review documents examination techniques, sonographic features and clinical considerations in ultrasound assessment of gynecological tumors. The methodology of gynecological cancer staging, including assessment of local tumor extent, lymph nodes and distant metastases, is described. With increased technical quality, sonography has become an accurate staging method for early and advanced gynecological tumors. Other complementary imaging techniques, such as computed tomography and magnetic resonance imaging, can be used as an adjunct to ultrasound in specific cases, but are not essential to tumor staging if sonography is performed by a specialist in gynecological oncology. Ultrasound is established as the method of choice for evaluating local extent of endometrial cancer and is the most important imaging method for the differential diagnosis of benign and malignant ovarian tumors. Ultrasound can be used to detect early as well as locally advanced cancers that extend from the vagina, cervix or other locations to the paracolpium, parametria, rectum and sigmoid colon, urinary bladder and other adjacent organs or structures. In cases of ureteric involvement, ultrasound is also helpful in locating the site of obstruction. Furthermore, it is specific for the detection of extrapelvic tumor spread to the abdominal cavity in the form of parietal or visceral carcinomatosis, omental and/or mesenteric infiltration. Ultrasound can be used to assess changes in infiltrated lymph nodes, including demonstration of characteristic sonomorphologic and vascular patterns. Vascular patterns are particularly well visualized in peripheral nodes using high resolution linear array probes or in the pelvis using high-frequency probes. The presence of peripheral or mixed vascularity or displacement of vessels seems to be the sole criterion in the diagnosis of metastatic or lymphomatous nodes. In the investigation of distant metastases, if a normal visceral organ or characteristic diffuse or

  8. Refractive outcomes comparison between the Lenstar LS 900® optical biometry and immersion A-scan ultrasound.

    PubMed

    Naicker, Palanyraj; Sundralingam, Siva; Peyman, Mohammadreza; Juana, Azida; Mohamad, Nor Fadhilah; Win, Maung Maung; Loo, Angela; Subrayan, Visvaraja

    2015-08-01

    To determine the accuracy of intraocular lens (IOL) calculations in eyes undergoing phacoemulsification cataract surgery with IOL implantation using immersion A-scan ultrasound (US) and Lenstar LS 900(®) biometry. In this prospective study, 200 eyes of 200 patients were randomized to undergo either Lenstar LS 900(®) or immersion A-scan US biometry to determine the IOL dioptric power prior to phacoemulsification cataract surgery. Post-operative refractive outcomes of these two groups of patients were compared. The result showed no significant difference between the target spherical equivalent (SE) and the post-operative SE value by the Lenstar LS 900(®) (p value = 0.632) or immersion A-scan US biometry (p value = 0.438) devices. The magnitude of difference between the two biometric devices were not significantly different (p value = 0.868). There was no significant difference in the predicted post-operative refractive outcome between immersion A-scan US biometry and Lenstar LS 900(®). Based on the results, the immersion A-scan US technique is as accurate as Lenstar LS 900(®) in the hands of an experienced operator.

  9. Performance of short-time spectral parametric methods for reducing the variance of the Doppler ultrasound mean instantaneous frequency estimation.

    PubMed

    Sava, H; Durand, L G; Cloutier, G

    1999-05-01

    To achieve an accurate estimation of the instantaneous turbulent velocity fluctuations downstream of prosthetic heart valves in vivo, the variability of the spectral method used to measure the mean frequency shift of the Doppler signal (i.e. the Doppler velocity) should be minimised. This paper investigates the performance of various short-time spectral parametric methods such as the short-time Fourier transform, autoregressive modelling based on two different approaches, autoregressive moving average modelling based on the Steiglitz-McBride method, and Prony's spectral method. A simulated Doppler signal was used to evaluate the performance of the above mentioned spectral methods and Gaussian noise was added to obtain a set of signals with various signal-to-noise ratios. Two different parameters were used to evaluate the performance of each method in terms of variability and accurate matching of the theoretical Doppler mean instantaneous frequency variation within the cardiac cycle. Results show that autoregressive modelling outperforms the other investigated spectral techniques for window lengths varying between 1 and 10 ms. Among the autoregressive algorithms implemented, it is shown that the maximum entropy method based on a block data processing technique gives the best results for a signal-to-noise ratio of 20 dB. However, at 10 and 0 dB, the Levinson-Durbin algorithm surpasses the performance of the maximum entropy method. It is expected that the intrinsic variance of the spectral methods can be an important source of error for the estimation of the turbulence intensity. The range of this error varies from 0.38% to 24% depending on the parameters of the spectral method and the signal-to-noise ratio. PMID:10505377

  10. Frequency Agile Tm,Ho:YLF Local Oscillator for a Scanning Doppler wind Lidar in Earth Orbit

    NASA Technical Reports Server (NTRS)

    Menzies, Robert T.; Hemmati, Hamid; Esproles, Carlos

    1997-01-01

    A compact cw Tm,Ho:YLF laser with single-mode tunability over +/-4 GHz has been developed into a modular unit containing an isolator and photomixer for offset tuning of the LO from a master oscillator which controls the frequency of a Doppler lidar transmitter. This and an alternative diode laser LO will be described.

  11. Experimental investigation of the effect of stiffness, exposure time and scan direction on the dimension of ultrasound histotripsy lesions.

    PubMed

    Xu, Jin; Bigelow, Timothy A

    2011-11-01

    Histotripsy uses high-intensity focused ultrasound to create energetic bubble clouds inside tissue to liquefy a region and has the advantages of higher contrast B-mode monitoring and sharp borders. This study experimentally investigated the effects of stiffness, exposure time and scan direction on the size of histotripsy-induced lesions in agar samples. A targeted region 0.45 cm wide (lateral) and 0.6 cm deep (axial) was scanned with the step sizes of 0.075 cm and 0.3 cm, respectively. The single-element spherically focused source (1.1 MHz, 6.34 cm focal length, f/1) had the peak compressional and rarefactional pressures of approximately 102 and 17 MPa. Pulses consisted of 20-cycle sine wave tone bursts with a burst period of 3 ms and exposure time of 15, 30 or 60 s. Also, both inward and outward scan direction were tested along the beam axis. The liquefied lesions generally had a larger size than the initially targeted region with larger sizes corresponding to softer agar and longer exposure. There was not a statistically significant difference in the lesion size with scan direction.

  12. Early life exposure to diagnostic radiation and ultrasound scans and risk of childhood cancer: case-control study

    PubMed Central

    Simpson, Jill; Neta, Gila; Berrington de Gonzalez, Amy; Ansell, Pat; Linet, Martha S; Ron, Elaine; Roman, Eve

    2011-01-01

    Objective To examine childhood cancer risks associated with exposure to diagnostic radiation and ultrasound scans in utero and in early infancy (age 0-100 days). Design Case-control study. Setting England and Wales. Participants 2690 childhood cancer cases and 4858 age, sex, and region matched controls from the United Kingdom Childhood Cancer Study (UKCCS), born 1976-96. Main outcome measures Risk of all childhood cancer, leukaemia, lymphoma, and central nervous system tumours, measured by odds ratios. Results Logistic regression models conditioned on matching factors, with adjustment for maternal age and child’s birth weight, showed no evidence of increased risk of childhood cancer with in utero exposure to ultrasound scans. Some indication existed of a slight increase in risk after in utero exposure to x rays for all cancers (odds ratio 1.l4, 95% confidence interval 0.90 to 1.45) and leukaemia (1.36, 0.91 to 2.02), but this was not statistically significant. Exposure to diagnostic x rays in early infancy (0-100 days) was associated with small, non-significant excess risks for all cancers and leukaemia, as well as increased risk of lymphoma (odds ratio 5.14, 1.27 to 20.78) on the basis of small numbers. Conclusions Although the results for lymphoma need to be replicated, all of the findings indicate possible risks of cancer from radiation at doses lower than those associated with commonly used procedures such as computed tomography scans, suggesting the need for cautious use of diagnostic radiation imaging procedures to the abdomen/pelvis of the mother during pregnancy and in children at very young ages. PMID:21310791

  13. Comparison of 99m technetium hexamethylpropylene-amine oxime labelled leucocyte with 111-indium tropolonate labelled granulocyte scanning and ultrasound in the diagnosis of intra-abdominal abscess.

    PubMed Central

    Weldon, M J; Joseph, A E; French, A; Saverymuttu, S H; Maxwell, J D

    1995-01-01

    Fifty patients with suspected intra-abdominal abscess were investigated prospectively with ultrasound and with 99mTc-hexamethylpropylene-amine oxime (HMPAO) isotope labelled mixed leucocytes, using 111-In tropolonate granulocyte scanning as the reference standard. Twenty five patients had inflammatory bowel disease (three were postoperative): 21 of these had Crohn's disease and four had ulcerative colitis. The remainder comprised nine with postoperative fever and 16 with fever and abdominal pain. An abscess was diagnosed when focal activity on serial 111-In tropolonate and 99m-Tc-HMPOA images at one, three, and 24 hours resulted in activity at least equal to liver activity at 24 hours. Thirteen abscesses were diagnosed using each type of white cell scanning, resulting in 100% sensitivity for 99m-Tc-HMPAO compared with 111-In tropolonate. Bowel inflammation was easily distinguished from abscess on serial images. Eight of these 13 abscesses were detected by ultrasound. Altogether 17 abscesses were found. Ultrasound detected 12, including four liver abscesses which were not purulent and had not been detected by white cell scanning. Ultrasound had a sensitivity of 71% (12 of 17) and a specificity of 87% (33 of 38) using all confirmed abscesses as the reference standard. White cell scanning showed a sensitivity of 76% (13 of 17: as a result of the four non-purulent liver abscesses) and a specificity of 100%. 99m-Tc-HMPAO scanning is as accurate as 111-In tropolonate scanning, and has several advantages including simplicity, availability, superior image quality, and reduced radiation dose. Both methods are more sensitive and specific than ultrasound for intra-abdominal abscess detection but ultrasound is advisable if a neutrophil infiltrate is not suspected. Images Figure 1 Figure 2 Figure 3 PMID:7489945

  14. SCAN+

    SciTech Connect

    Kenneth Krebs, John Svoboda

    2009-11-01

    SCAN+ is a software application specifically designed to control the positioning of a gamma spectrometer by a two dimensional translation system above spent fuel bundles located in a sealed spent fuel cask. The gamma spectrometer collects gamma spectrum information for the purpose of spent fuel cask fuel loading verification. SCAN+ performs manual and automatic gamma spectrometer positioning functions as-well-as exercising control of the gamma spectrometer data acquisitioning functions. Cask configuration files are used to determine the positions of spent fuel bundles. Cask scanning files are used to determine the desired scan paths for scanning a spent fuel cask allowing for automatic unattended cask scanning that may take several hours.

  15. The use of non-contrast computed tomography and color Doppler ultrasound in the characterization of urinary stones - preliminary results

    PubMed Central

    Bulakçı, Mesut; Tefik, Tzevat; Akbulut, Fatih; Örmeci, Mehmet Tolgahan; Beşe, Caner; Şanlı, Öner; Oktar, Tayfun; Salmaslıoğlu, Artür

    2015-01-01

    Objective To investigate the role of density value in computed tomography (CT) and twinkling artifact observed in color Doppler analysis for the prediction of the mineral composition of urinary stones. Material and methods A total of 42 patients who were operated via percutaneous or endoscopic means and had undergone abdominal non-contrast CT and color Doppler ultrasonography examinations were included in the study. X-ray diffraction method was utilized to analyze a total of 86 stones, and the correlations between calculated density values and twinkling intensities with stone types were investigated for each stone. Results Analyses of extracted stones revealed the presence of 40 calcium oxalate monohydrate, 12 calcium oxalate dihydrate, 9 uric acid, 11 calcium phosphate, and 14 cystine stones. The density values were calculated as 1499±269 Hounsfield Units (HU) for calcium oxalate monohydrate, 1505±221 HU for calcium oxalate dihydrate, 348±67 HU for uric acid, 1106±219 HU for calcium phosphate, and 563±115 HU for cystine stones. The artifact intensities were determined as grade 0 in 15, grade 1 in 32, grade 2 in 24, and grade 3 in 15 stones. Conclusion In case the density value of the stone is measured below 780 HU and grade 3 artifact intensity is determined, it can be inferred that the mineral composition of the stone tends to be cystine. PMID:26623143

  16. Venous Ultrasound (Extremities)

    MedlinePlus

    ... waves. Ultrasound imaging, also called ultrasound scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ...

  17. Head and Neck Veins of the Mouse. A Magnetic Resonance, Micro Computed Tomography and High Frequency Color Doppler Ultrasound Study.

    PubMed

    Mancini, Marcello; Greco, Adelaide; Tedeschi, Enrico; Palma, Giuseppe; Ragucci, Monica; Bruzzone, Maria Grazia; Coda, Anna Rita Daniela; Torino, Enza; Scotti, Alessandro; Zucca, Ileana; Salvatore, Marco

    2015-01-01

    To characterize the anatomy of the venous outflow of the mouse brain using different imaging techniques. Ten C57/black male mice (age range: 7-8 weeks) were imaged with high-frequency Ultrasound, Magnetic Resonance Angiography and ex-vivo Microcomputed tomography of the head and neck. Under general anesthesia, Ultrasound of neck veins was performed with a 20 MHz transducer; head and neck Magnetic Resonance Angiography data were collected on 9.4 T or 7 T scanners, and ex-vivo Microcomputed tomography angiography was obtained by filling the vessels with a radiopaque inert silicone rubber compound. All procedures were approved by the local ethical committee. The dorsal intracranial venous system is quite similar in mice and humans. Instead, the mouse Internal Jugular Veins are tiny vessels receiving the sigmoid sinuses and tributaries from cerebellum, occipital lobe and midbrain, while the majority of the cerebral blood, i.e. from the olfactory bulbs and fronto-parietal lobes, is apparently drained through skull base connections into the External Jugular Vein. Three main intra-extracranial anastomoses, absent in humans, are: 1) the petrosquamous sinus, draining into the posterior facial vein, 2) the veins of the olfactory bulb, draining into the superficial temporal vein through a foramen of the frontal bone 3) the cavernous sinus, draining in the External Jugular Vein through a foramen of the sphenoid bone. The anatomical structure of the mouse cranial venous outflow as depicted by Ultrasound, Microcomputed tomography and Magnetic Resonance Angiography is different from humans, with multiple connections between intra- and extra-cranial veins. PMID:26067061

  18. Head and Neck Veins of the Mouse. A Magnetic Resonance, Micro Computed Tomography and High Frequency Color Doppler Ultrasound Study

    PubMed Central

    Mancini, Marcello; Greco, Adelaide; Tedeschi, Enrico; Palma, Giuseppe; Ragucci, Monica; Bruzzone, Maria Grazia; Coda, Anna Rita Daniela; Torino, Enza; Scotti, Alessandro; Zucca, Ileana; Salvatore, Marco

    2015-01-01

    To characterize the anatomy of the venous outflow of the mouse brain using different imaging techniques. Ten C57/black male mice (age range: 7-8 weeks) were imaged with high-frequency Ultrasound, Magnetic Resonance Angiography and ex-vivo Microcomputed tomography of the head and neck. Under general anesthesia, Ultrasound of neck veins was performed with a 20MHz transducer; head and neck Magnetic Resonance Angiography data were collected on 9.4T or 7T scanners, and ex-vivo Microcomputed tomography angiography was obtained by filling the vessels with a radiopaque inert silicone rubber compound. All procedures were approved by the local ethical committee. The dorsal intracranial venous system is quite similar in mice and humans. Instead, the mouse Internal Jugular Veins are tiny vessels receiving the sigmoid sinuses and tributaries from cerebellum, occipital lobe and midbrain, while the majority of the cerebral blood, i.e. from the olfactory bulbs and fronto-parietal lobes, is apparently drained through skull base connections into the External Jugular Vein. Three main intra-extracranial anastomoses, absent in humans, are: 1) the petrosquamous sinus, draining into the posterior facial vein, 2) the veins of the olfactory bulb, draining into the superficial temporal vein through a foramen of the frontal bone 3) the cavernous sinus, draining in the External Jugular Vein through a foramen of the sphenoid bone. The anatomical structure of the mouse cranial venous outflow as depicted by Ultrasound, Microcomputed tomography and Magnetic Resonance Angiography is different from humans, with multiple connections between intra- and extra- cranial veins. PMID:26067061

  19. Peak velocity overestimation and linear-array spectral Doppler.

    PubMed

    Eicke, B M; Kremkau, F W; Hinson, H; Tegeler, C H

    1995-04-01

    Ultrasound instruments are used to evaluate blood flow velocities in the human body. Most clinical instruments perform velocity calculations based on the Doppler principle and measure the frequency shift of a reflected ultrasound beam. Doppler-only instruments use single-frequency, single-crystal transducers. Linear- and annular-array multiple-crystal transducers are used for duplex scanning (simultaneous B-mode image and Doppler). Clinical interpretation relies primarily on determination of peak velocities or frequency shifts as identified by the Doppler spectrum. Understanding of the validity of these measurements is important for instruments in clinical use. The present study examined the accuracy with which several ultrasound instruments could estimate velocities based on the identification of the peak of the Doppler spectrum, across a range of different angles of insonation, on a Doppler string phantom. The string was running in a water tank at constant speeds of 50, 100, and 150 cm/sec and also in a sine wave pattern at 100- or 150-cm/sec amplitude. Angles of insonation were 30, 45, 60, and 70 degrees. The single-frequency, single-crystal transducers (PC Dop 842, 2-MHz pulsed-wave, 4-MHz continuous-wave) provided acceptably accurate velocity estimates at all tested velocities independent of the angle of insonation. All duplex Doppler instruments with linear-array transducers (Philips P700, 5.0-MHz; Hewlett-Packard Sonos 1000, 7.5-MHz; ATL Ultramark 9 HDI, 7.5-MHz) exhibited a consistent overestimation of the true flow velocity due to increasing intrinsic spectral broadening with increasing angle of insonation.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Protocol of plain radiographs, hip ultrasound, and triple phase bone scans in the evaluation of the painful pediatric hip

    SciTech Connect

    Alexander, J.E.; Seibert, J.J.; Aronson, J.; Williamson, S.L.; Glasier, C.M.; Rodgers, A.B.; Corbitt, S.L.

    1988-04-01

    A useful protocol for the evaluation of hip pain in the pediatric patient, using a combination of plain radiographs, hip ultrasound (US), and triple phase radionuclide bone scans is presented. Patients with hip pain were initially evaluated by plain radiographs of the pelvis and hips. If no diagnosis was reached, the hips were studied for effusions by real-time hip ultrasonography. If an effusion was present, the joint was aspirated for diagnosis. If no effusion was present by US or if no diagnosis was reached by aspiration, triple phase radionuclide bone scans were performed. Fifty patients were evaluated by this prospective protocol, and the diagnosis was reached in 48 of the 50 cases (10 by plain radiographs, 16 by US, and aspiration of the joint, and 22 by triple phase bone scans). Hip effusions were found in 20 patients by US, with no false positives or false negatives. Previous studies for detecting effusions by US have emphasized absolute measurements of the capsular width, but we report a typical appearance of the hip capsule when fluid is present (a bulging convex capsule). When no effusion is present, the capsule is concave and parallels the long axis of the femoral neck.

  1. An introduction to the use of diagnostic ultrasound.

    PubMed

    Sweet, E M; Arneil, G C

    1975-10-01

    This article is meant to serve as a simple introduction to diagnostic ultrasound, explaining the nature of sonar and the basic equipment for its production and use. A scans, B scans, time-position scans, and Doppler-shift techniques are described, with some examples of the clinical applications of each. Some recent innovations such as scan conversion to improve gray scaling and electrocardiographically triggered cardiac sector scans are mentioned. The limitations of the technique are indicated, with measures that can be adopted to reduce them. The safety of the procedure is emphasized, with its freedom from the known biological effects of ionizing radiation.

  2. Genome-Wide Linkage Scan for Quantitative Trait Loci Underlying Normal Variation in Heel Bone Ultrasound Measures

    PubMed Central

    Lee, M.; Choh, A.C.; Williams, K.D.; Schroeder, V.; Dyer, T.D.; Blangero, J.; Cole, S.A.; Chumlea, WM.C.; Duren, D.L.; Sherwood, R.J.; Siervogel, R.M.; Towne, B.; Czerwinski, S.A.

    2012-01-01

    Quantitative ultrasound (QUS) traits are correlated with bone mineral density (BMD), but predict risk for future fracture independent of BMD. Only a few studies, however, have sought to identify specific genes influencing calcaneal QUS measures. The aim of this study was to conduct a genome-wide linkage scan to identify quantitative trait loci (QTL) influencing normal variation in QUS traits. QUS measures were collected from a total of 719 individuals (336 males and 383 females) from the Fels Longitudinal Study who have been genotyped and have at least one set of QUS measurements. Participants ranged in age from 18.0 to 96.6 years and were distributed across 110 nuclear and extended families. Using the Sahara ® bone sonometer, broadband ultrasound attenuation (BUA), speed of sound (SOS) and stiffness index (QUI) were collected from the right heel. Variance components based linkage analysis was performed on the three traits using 400 polymorphic short tandem repeat (STR) markers spaced approximately 10 cM apart across the autosomes to identify QTL influencing the QUS traits. Age, sex, and other significant covariates were simultaneously adjusted. Heritability estimates (h2) for the QUS traits ranged from 0.42 to 0.57. Significant evidence for a QTL influencing BUA was found on chromosome 11p15 near marker D11S902 (LOD = 3.11). Our results provide additional evidence for a QTL on chromosome 11p that harbors a potential candidate gene(s) related to BUA and bone metabolism. PMID:22237995

  3. Numerical simulation of ultrasound thermotherapy of brain with a scanned focus transducer

    NASA Astrophysics Data System (ADS)

    Behnia, Sohrab; Ghalichi, Farzan; Jafari, Amin; Bonabi, Ashkan

    2005-04-01

    Brain tumors are one of the most difficult ones to treat. The margin between destruction of the tumor and damage to the surrounding tissue is narrow in the brain. Ultrasound could be an effective treatment because of its ability to propagate deep in tissue and induce temperature rise at the focus while leaving the surrounding tissue intact. This study investigates whether using a fix-focus transducer could destroy brain tumor cells, in a cost effective manner which reduces the treatment time significantly. In this work an appropriate fix-focus transducer was designed considering effective parameters and limitations which are dominant in this case. Then a real 2-D brain model was constructed from a MR image. A piece of the skull bone has been removed to allow ultrasound to propagate into the brain. The resultant pressure field and the temperature rise were calculated by Rayleigh integral and bio-heat equation on the model. The obtained results were promising indicating that toxic temperatures could be obtained in short treatment times. This could be of great advantage especially in treating primary brain tumors.

  4. Can single use negative pressure wound therapy be an alternative method to manage keloid scarring? A preliminary report of a clinical and ultrasound/colour-power-doppler study.

    PubMed

    Fraccalvieri, Marco; Sarno, Antonino; Gasperini, Stefano; Zingarelli, Enrico; Fava, Raffaella; Salomone, Marco; Bruschi, Stefano

    2013-06-01

    Keloid scarring represents a pathological healing where primary healing phenomenon is deviated from normal. Pico is a single use negative pressure wound therapy system originally introduced to manage open or just closed wounds. Pico dressing is made of silicone, and distributes an 80 mmHg negative pressure across wound bed. Combination of silicon layer and continuous compression could be a valid method to manage keloid scarring. Since November 2011, three patients were enrolled and evaluated before negative pressure treatment, at end of treatment (1 month) and 2 months later, through Vancouver Scar Scale (VSS), Visual Analog Scale (VAS) and a scoring system for itching. Ultrasound (US) and colour-power-doppler (CPD) examination was performed to evaluate thickness and vascularisation of the scar. One patient was discharged from study after 1 week. In last two patients, VSS, VAS and itching significantly improved after 1 month therapy and the results were stable after 2 months without any therapy. At end of therapy, the 'appearance of palisade vessels' disappeared in both cases at CPD exam; US showed a thickness reduction (average 43·8%). We propose a well-tolerated, non invasive treatment to manage keloid scarring. Prospective studies are necessary to investigate whether these preliminary observations are confirmed.

  5. Non-invasive assessment of bone quantity and quality in human trabeculae using scanning ultrasound imaging

    NASA Astrophysics Data System (ADS)

    Xia, Yi

    Fractures and associated bone fragility induced by osteoporosis and osteopenia are widespread health threat to current society. Early detection of fracture risk associated with bone quantity and quality is important for both the prevention and treatment of osteoporosis and consequent complications. Quantitative ultrasound (QUS) is an engineering technology for monitoring bone quantity and quality of humans on earth and astronauts subjected to long duration microgravity. Factors currently limiting the acceptance of QUS technology involve precision, accuracy, single index and standardization. The objective of this study was to improve the accuracy and precision of an image-based QUS technique for non-invasive evaluation of trabecular bone quantity and quality by developing new techniques and understanding ultrasound/tissue interaction. Several new techniques have been developed in this dissertation study, including the automatic identification of irregular region of interest (iROI) in bone, surface topology mapping (STM) and mean scattering spacing (MSS) estimation for evaluating trabecular bone structure. In vitro results have shown that (1) the inter- and intra-observer errors in QUS measurement were reduced two to five fold by iROI compared to previous results; (2) the accuracy of QUS parameter, e.g., ultrasound velocity (UV) through bone, was improved 16% by STM; and (3) the averaged trabecular spacing can be estimated by MSS technique (r2=0.72, p<0.01). The measurement errors of BUA and UV introduced by the soft tissue and cortical shells in vivo can be quantified by developed foot model and simplified cortical-trabecular-cortical sandwich model, which were verified by the experimental results. The mechanisms of the errors induced by the cortical and soft tissues were revealed by the model. With developed new techniques and understanding of sound-tissue interaction, in vivo clinical trail and bed rest study were preformed to evaluate the performance of QUS in

  6. SCAN+

    2009-11-01

    SCAN+ is a software application specifically designed to control the positioning of a gamma spectrometer by a two dimensional translation system above spent fuel bundles located in a sealed spent fuel cask. The gamma spectrometer collects gamma spectrum information for the purpose of spent fuel cask fuel loading verification. SCAN+ performs manual and automatic gamma spectrometer positioning functions as-well-as exercising control of the gamma spectrometer data acquisitioning functions. Cask configuration files are used to determinemore » the positions of spent fuel bundles. Cask scanning files are used to determine the desired scan paths for scanning a spent fuel cask allowing for automatic unattended cask scanning that may take several hours.« less

  7. 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

  8. 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 ...

  9. Internal iliac and uterine arteries Doppler ultrasound in the assessment of normotensive and chronic hypertensive pregnant women

    PubMed Central

    Guedes-Martins, L.; Cunha, A.; Saraiva, J.; Gaio, R.; Macedo, F.; Almeida, H.

    2014-01-01

    The objective of this work was to compare Doppler flows pulsatility index (PI) and resistance indexes (RI) of uterine and internal iliac arteries during pregnancy in low risk women and in those with stage-1 essential hypertension. From January 2010 and December 2012, a longitudinal and prospective study was carried out in 103 singleton uneventful pregnancies (72 low-risk pregnancies and 31 with stage 1 essential hypertension)at the 1st, 2nd and 3rd trimesters. Multiple linear regression models, fitted using generalized least squares and whose errors were allowed to be correlated and/or have unequal variances, were employed; a model for the relative differences of both arteries impedance was utilized. In both groups, uterine artery PI and RI exhibited a gestational age related decreasing trend whereas internal iliac artery PI and RI increased. The model testing the hemodynamic adaptation in women with and without hypertension showed similar trend. Irrespective of blood pressure conditions, the internal iliac artery resistance pattern contrasts with the capacitance pattern of its immediate pelvic division, suggesting a pregnancy-related regulatory mechanism in the pelvic circulation. PMID:24445576

  10. Christian Doppler is 200 years young.

    PubMed

    Bollinger, Alfred; Partsch, Hugo

    2003-11-01

    Christian Doppler was born 200 years ago in Salzburg, Austria, on November 29, 1803, worked in Prague and Vienna and died 150 years ago in Venice. In an article of eight pages he described the principle, which made him famous. It appeared in 1842 with the exotic title: "On the Coloured Light of the Double Stars and Certain Other Stars of the Heaven". The validity of his principle for velocity measurement was confirmed by trumpet sounds produced on a train moving towards and away from the observer. Around 1960 Japanese scientists suggested that flow velocity in blood vessels could be determined by analysing the difference of frequency between emitted and backscattered ultrasound. Rushmer and coworkers built machines suitable for medicine in Seattle, where Eugene Strandness recognized their potential and applied them in first studies. In 1967 the technique jumped to Europe and started to be used worldwide. Already by using continuous wave ultrasound it was possible to diagnose occlusive disease of neck and limb arteries, venous thrombosis and valvular insufficiency with accuracy. Measurements of postestenotic ankle blood pressure were facilitated by Doppler sensing. Over the years more sophisticated instruments were developed. Pulsed emission of ultrasound waves opened a way to study flow velocity profiles across large vessels. By combining the method with A or B mode ultrasound blood flow could be quantified and finally perfused segments of blood vessels visualized. Duplex scanning in its simple and then in its colour coded version is nowadays the standard non-invasive technique that nobody would like to miss. Vascular territories like intracranial, renal and intestinal arteries can also be explored. For the assessment of microvascular flow in skin and mucosae laser Doppler instruments were introduced.

  11. Christian Doppler is 200 years young.

    PubMed

    Bollinger, Alfred; Partsch, Hugo

    2003-11-01

    Christian Doppler was born 200 years ago in Salzburg, Austria, on November 29, 1803, worked in Prague and Vienna and died 150 years ago in Venice. In an article of eight pages he described the principle, which made him famous. It appeared in 1842 with the exotic title: "On the Coloured Light of the Double Stars and Certain Other Stars of the Heaven". The validity of his principle for velocity measurement was confirmed by trumpet sounds produced on a train moving towards and away from the observer. Around 1960 Japanese scientists suggested that flow velocity in blood vessels could be determined by analysing the difference of frequency between emitted and backscattered ultrasound. Rushmer and coworkers built machines suitable for medicine in Seattle, where Eugene Strandness recognized their potential and applied them in first studies. In 1967 the technique jumped to Europe and started to be used worldwide. Already by using continuous wave ultrasound it was possible to diagnose occlusive disease of neck and limb arteries, venous thrombosis and valvular insufficiency with accuracy. Measurements of postestenotic ankle blood pressure were facilitated by Doppler sensing. Over the years more sophisticated instruments were developed. Pulsed emission of ultrasound waves opened a way to study flow velocity profiles across large vessels. By combining the method with A or B mode ultrasound blood flow could be quantified and finally perfused segments of blood vessels visualized. Duplex scanning in its simple and then in its colour coded version is nowadays the standard non-invasive technique that nobody would like to miss. Vascular territories like intracranial, renal and intestinal arteries can also be explored. For the assessment of microvascular flow in skin and mucosae laser Doppler instruments were introduced. PMID:14694774

  12. Gray-scale and color duplex Doppler ultrasound of hand joints in the evaluation of disease activity and treatment in rheumatoid arthritis

    PubMed Central

    Ivanac, Gordana; Morović-Vergles, Jadranka; Brkljačić, Boris

    2015-01-01

    Aim To evaluate the role of gray-scale and color duplex-Doppler ultrasound (CDUS) in diagnosis of changes of hand joints and assessment of treatment efficacy in patients with rheumatoid arthritis (RA) by comparing qualitative and quantitative US parameters with clinical and laboratory indicators of disease activity. Methods Ulnocarpal (UC), metacarpophalangeal (MCP), and proximal interphalangeal (PIP) joints in 30 patients with RA were examined by gray-scale and CDUS before and after six months of treatment. Morphologic and quantitative Doppler findings (synovial thickness, effusion quantity, vascularization degree, resistance index, velocities) were compared with clinical indicators of disease progression: disease activity score (DAS 28), Health Assessment Questionnaire (HAQ), rheumatoid factor (RF), erythrocyte sedimentation rate (ESR), and C reactive protein (CRP). Results Clinical indicators changed significantly after treatment: ESR from 38.1 ± 22.4 mm/h to 27.8 ± 20.9 mm/h (P = 0.013), DAS 28 from 5.47 ± 1.56 to 3.87 ± 1.65 (P < 0.001), and HAQ from 1.26 ± 0.66 to 0.92 ± 0.74 (P = 0.030), indicating therapeutic effectiveness. In all MCP and UC joints we observed a significant change in at least one US parameter, in 6 out of 12 joints we observed a significant change in ≥2 parameters, and in 2 UC joints we observed significant changes in ≥3 parameters. The new finding was that the cut-off values of resistance index of 0.40 at baseline and of 0.55 after the treatment indicated the presence of active disease and the efficacy of treatment, respectively; also it was noticed that PIP joints can be omitted from examination protocol. Conclusion Gray scale and CDUS are useful in diagnosis of changes in UC and MCP joints of patients with RA and in monitoring the treatment efficacy. PMID:26088853

  13. A 3D Freehand Ultrasound System for Multi-view Reconstructions from Sparse 2D Scanning Planes

    PubMed Central

    2011-01-01

    Background A significant limitation of existing 3D ultrasound systems comes from the fact that the majority of them work with fixed acquisition geometries. As a result, the users have very limited control over the geometry of the 2D scanning planes. Methods We present a low-cost and flexible ultrasound imaging system that integrates several image processing components to allow for 3D reconstructions from limited numbers of 2D image planes and multiple acoustic views. Our approach is based on a 3D freehand ultrasound system that allows users to control the 2D acquisition imaging using conventional 2D probes. For reliable performance, we develop new methods for image segmentation and robust multi-view registration. We first present a new hybrid geometric level-set approach that provides reliable segmentation performance with relatively simple initializations and minimum edge leakage. Optimization of the segmentation model parameters and its effect on performance is carefully discussed. Second, using the segmented images, a new coarse to fine automatic multi-view registration method is introduced. The approach uses a 3D Hotelling transform to initialize an optimization search. Then, the fine scale feature-based registration is performed using a robust, non-linear least squares algorithm. The robustness of the multi-view registration system allows for accurate 3D reconstructions from sparse 2D image planes. Results Volume measurements from multi-view 3D reconstructions are found to be consistently and significantly more accurate than measurements from single view reconstructions. The volume error of multi-view reconstruction is measured to be less than 5% of the true volume. We show that volume reconstruction accuracy is a function of the total number of 2D image planes and the number of views for calibrated phantom. In clinical in-vivo cardiac experiments, we show that volume estimates of the left ventricle from multi-view reconstructions are found to be in better

  14. Ultrasound-guided versus computed tomography-scan guided biopsy of pleural-based lung lesions

    PubMed Central

    Khosla, Rahul; McLean, Anna W; Smith, Jessica A

    2016-01-01

    Background: Computed tomography (CT) guided biopsies have long been the standard technique to obtain tissue from the thoracic cavity and is traditionally performed by interventional radiologists. Ultrasound (US) guided biopsy of pleural-based lesions, performed by pulmonologists is gaining popularity and has the advantage of multi-planar imaging, real-time technique, and the absence of radiation exposure to patients. In this study, we aim to determine the diagnostic accuracy, the time to diagnosis after the initial consult placement, and the complications rates between the two different modalities. Methods: A retrospective study of electronic medical records was done of patients who underwent CT-guided biopsies and US-guided biopsies for pleural-based lesions between 2005 and 2014 and the data collected were analyzed for comparing the two groups. Results: A total of 158 patients underwent 162 procedures during the study period. 86 patients underwent 89 procedures in the US group, and 72 patients underwent 73 procedures in the CT group. The overall yield in the US group was 82/89 (92.1%) versus 67/73 (91.8%) in the CT group (P = 1.0). Average days to the procedure was 7.2 versus 17.5 (P = 0.00001) in the US and CT group, respectively. Complication rate was higher in CT group 17/73 (23.3%) versus 1/89 (1.1%) in the US group (P < 0.0001). Conclusions: For pleural-based lesions the diagnostic accuracy of US guided biopsy is similar to that of CT-guided biopsy, with a lower complication rate and a significantly reduced time to the procedure. PMID:27625440

  15. Ultrasound-guided versus computed tomography-scan guided biopsy of pleural-based lung lesions

    PubMed Central

    Khosla, Rahul; McLean, Anna W; Smith, Jessica A

    2016-01-01

    Background: Computed tomography (CT) guided biopsies have long been the standard technique to obtain tissue from the thoracic cavity and is traditionally performed by interventional radiologists. Ultrasound (US) guided biopsy of pleural-based lesions, performed by pulmonologists is gaining popularity and has the advantage of multi-planar imaging, real-time technique, and the absence of radiation exposure to patients. In this study, we aim to determine the diagnostic accuracy, the time to diagnosis after the initial consult placement, and the complications rates between the two different modalities. Methods: A retrospective study of electronic medical records was done of patients who underwent CT-guided biopsies and US-guided biopsies for pleural-based lesions between 2005 and 2014 and the data collected were analyzed for comparing the two groups. Results: A total of 158 patients underwent 162 procedures during the study period. 86 patients underwent 89 procedures in the US group, and 72 patients underwent 73 procedures in the CT group. The overall yield in the US group was 82/89 (92.1%) versus 67/73 (91.8%) in the CT group (P = 1.0). Average days to the procedure was 7.2 versus 17.5 (P = 0.00001) in the US and CT group, respectively. Complication rate was higher in CT group 17/73 (23.3%) versus 1/89 (1.1%) in the US group (P < 0.0001). Conclusions: For pleural-based lesions the diagnostic accuracy of US guided biopsy is similar to that of CT-guided biopsy, with a lower complication rate and a significantly reduced time to the procedure.

  16. The effect of isometric exercise of the hand on the synovial blood flow in patients with rheumatoid arthritis measured by color Doppler ultrasound.

    PubMed

    Ellegaard, Karen; Torp-Pedersen, Søren; Lund, Hans; Pedersen, Kirsten; Henriksen, Marius; Danneskiold-Samsøe, Bente; Bliddal, Henning

    2013-01-01

    In 90% of patients with rheumatoid arthritis (RA), the joints of the hand are affected. Studies of grip strength training have not indicated a negative effect on disease activity after training. Introduction of ultrasound Doppler (USD) to measure increased blood flow induced by inflammation has made it possible to investigate the direct effect on blood supply in the synovium after training. In this case-control study, 24 patients with RA with USD activity in the wrist joint participated. The USD activity was measured by the color fraction (CF) (CF = colored pixels/total number of pixels in ROI). Twenty-four patients were assigned to an 8-week grip strength training program. At baseline and after 8 weeks of training, an USD examination of the wrist joint was performed. In the training group, we measured grip strength and pain in the wrist joint. Six patients withdrew from the training because of pain or change in medication. Eighteen patients served as control group. There was a modest, not significant, decrease in the CF in response to training (1.86%; P = 0.08). Grip strength increased 8.8% after training (P = 0.055). Pain in motion deceased after training (P = 0.04). No difference in the CF was seen between the training and control groups, neither at baseline nor at follow-up (P = 0.82 and P = 0.48). Patients withdrawing from training had a significantly higher CF than the other patients (P > 0.001). The results in this study might indicate that the flow in the synovium assessed by USD is not affected by grip strength training.

  17. Documentation and Instructions for Running Two Python Scripts that Aid in Setting up 3D Measurements using the Polytec 3D Scanning Laser Doppler Vibrometer.

    SciTech Connect

    Rohe, Daniel Peter

    2015-08-24

    Sandia National Laboratories has recently purchased a Polytec 3D Scanning Laser Doppler Vibrometer for vibration measurement. This device has proven to be a very nice tool for making vibration measurements, and has a number of advantages over traditional sensors such as accelerometers. The non-contact nature of the laser vibrometer means there is no mass loading due to measuring the response. Additionally, the laser scanning heads can position the laser spot much more quickly and accurately than placing an accelerometer or performing a roving hammer impact. The disadvantage of the system is that a significant amount of time must be invested to align the lasers with each other and the part so that the laser spots can be accurately positioned. The Polytec software includes a number of nice tools to aid in this procedure; however, certain portions are still tedious. Luckily, the Polytec software is readily extensible by programming macros for the system, so tedious portions of the procedure can be made easier by automating the process. The Polytec Software includes a WinWrap (similar to Visual Basic) editor and interface to run macros written in that programming language. The author, however, is much more proficient in Python, and the latter also has a much larger set of libraries that can be used to create very complex macros, while taking advantage of Python’s inherent readability and maintainability.

  18. Fluid mechanics of blood flow in human fetal left ventricles based on patient-specific 4D ultrasound scans.

    PubMed

    Lai, Chang Quan; Lim, Guat Ling; Jamil, Muhammad; Mattar, Citra Nurfarah Zaini; Biswas, Arijit; Yap, Choon Hwai

    2016-10-01

    The mechanics of intracardiac blood flow and the epigenetic influence it exerts over the heart function have been the subjects of intense research lately. Fetal intracardiac flows are especially useful for gaining insights into the development of congenital heart diseases, but have not received due attention thus far, most likely because of technical difficulties in collecting sufficient intracardiac flow data in a safe manner. Here, we circumvent such obstacles by employing 4D STIC ultrasound scans to quantify the fetal heart motion in three normal 20-week fetuses, subsequently performing 3D computational fluid dynamics simulations on the left ventricles based on these patient-specific heart movements. Analysis of the simulation results shows that there are significant differences between fetal and adult ventricular blood flows which arise because of dissimilar heart morphology, E/A ratio, diastolic-systolic duration ratio, and heart rate. The formations of ventricular vortex rings were observed for both E- and A-wave in the flow simulations. These vortices had sufficient momentum to last until the end of diastole and were responsible for generating significant wall shear stresses on the myocardial endothelium, as well as helicity in systolic outflow. Based on findings from previous studies, we hypothesized that these vortex-induced flow properties play an important role in sustaining the efficiency of diastolic filling, systolic pumping, and cardiovascular flow in normal fetal hearts. PMID:26676944

  19. Fluid mechanics of blood flow in human fetal left ventricles based on patient-specific 4D ultrasound scans.

    PubMed

    Lai, Chang Quan; Lim, Guat Ling; Jamil, Muhammad; Mattar, Citra Nurfarah Zaini; Biswas, Arijit; Yap, Choon Hwai

    2016-10-01

    The mechanics of intracardiac blood flow and the epigenetic influence it exerts over the heart function have been the subjects of intense research lately. Fetal intracardiac flows are especially useful for gaining insights into the development of congenital heart diseases, but have not received due attention thus far, most likely because of technical difficulties in collecting sufficient intracardiac flow data in a safe manner. Here, we circumvent such obstacles by employing 4D STIC ultrasound scans to quantify the fetal heart motion in three normal 20-week fetuses, subsequently performing 3D computational fluid dynamics simulations on the left ventricles based on these patient-specific heart movements. Analysis of the simulation results shows that there are significant differences between fetal and adult ventricular blood flows which arise because of dissimilar heart morphology, E/A ratio, diastolic-systolic duration ratio, and heart rate. The formations of ventricular vortex rings were observed for both E- and A-wave in the flow simulations. These vortices had sufficient momentum to last until the end of diastole and were responsible for generating significant wall shear stresses on the myocardial endothelium, as well as helicity in systolic outflow. Based on findings from previous studies, we hypothesized that these vortex-induced flow properties play an important role in sustaining the efficiency of diastolic filling, systolic pumping, and cardiovascular flow in normal fetal hearts.

  20. Application of the compound probability density function for characterization of breast masses in ultrasound B scans.

    PubMed

    Shankar, P M; Piccoli, C W; Reid, J M; Forsberg, F; Goldberg, B B

    2005-05-21

    The compound probability density function (pdf) is investigated for the ability of its parameters to classify masses in ultrasonic B scan breast images. Results of 198 images (29 malignant and 70 benign cases and two images per case) are reported and compared to the classification performance reported by us earlier in this journal. A new parameter, the speckle factor, calculated from the parameters of the compound pdf was explored to separate benign and malignant masses. The receiver operating characteristic curve for the parameter resulted in an A(z) value of 0.852. This parameter was combined with one of the parameters from our previous work, namely the ratio of the K distribution parameter at the site and away from the site. This combined parameter resulted in an A(z) value of 0.955. In conclusion, the parameters of the K distribution and the compound pdf may be useful in the classification of breast masses. These parameters can be calculated in an automated fashion. It should be possible to combine the results of the ultrasonic image analysis with those of traditional mammography, thereby increasing the accuracy of breast cancer diagnosis.

  1. 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

  2. Broadband ultrasound field mapping system using a wavelength tuned, optically scanned focused laser beam to address a Fabry Perot polymer film sensor.

    PubMed

    Zhang, Edward; Beard, Paul

    2006-07-01

    An optical system for rapidly mapping broad-band ultrasound fields with high spatial resolution has been developed. The transduction mechanism is based upon the detection of acoustically induced changes in the optical thickness of a thin polymer film acting as a Fabry Perot sensing interferometer (FPI). By using a PC-controlled galvanometer mirror to line-scan a focused laser beam over the surface of the FPI, and a wavelength-tuned phase bias control system to optimally set the FPI working point, a notional 1D ultrasound array was synthesized. This system enabled ultrasound fields to be mapped over an aperture of 40 mm, in 50-microm steps with an optically defined element size of 50 microm and an acquisition time of 50 ms per step. The sensor comprised a 38-microm polymer film FPI which was directly vacuum-deposited onto an impedance-matched polycarbonate backing stub. The -3 dB acoustic bandwidth of the sensor was 300 kHz to 28 MHz and the peak noise-equivalent-pressure was 10 kPa over a 20-MHz measurement bandwidth. To demonstrate the system, the outputs of various planar and focused pulsed ultrasound transducers with operating frequencies in the range 3.5 to 20 MHz were mapped. It is considered that this approach offers a practical and inexpensive alternative to piezoelectric-based arrays and scanning systems for rapid transducer field characterization and biomedical and industrial ultrasonic imaging applications. PMID:16889340

  3. Physical model from 3D ultrasound and magnetic resonance imaging scan data reconstruction of lumbosacral myelomeningocele in a fetus with Chiari II malformation.

    PubMed

    Werner, Heron; Lopes, Jorge; Tonni, Gabriele; Araujo Júnior, Edward

    2015-04-01

    Rapid prototyping is becoming a fast-growing and valuable technique for physical models in case of congenital anomalies. Manufacturing models are generally built from three-dimensional (3D) ultrasound, computed tomography, and fetal magnetic resonance imaging (MRI) scan data. Physical prototype has demonstrated to be clinically of value in case of complex fetal malformations and may improve antenatal management especially in cases of craniosynostosis, orofacial clefts, and giant epignathus. In addition, it may enhance parental bonding in visually impaired parents and have didactic value in teaching program. Hereby, the first 3D physical model from 3D ultrasound and MRI scan data reconstruction of lumbosacral myelomeningocele in a third trimester fetus affected by Chiari II malformation is reported. PMID:25686895

  4. Physical model from 3D ultrasound and magnetic resonance imaging scan data reconstruction of lumbosacral myelomeningocele in a fetus with Chiari II malformation.

    PubMed

    Werner, Heron; Lopes, Jorge; Tonni, Gabriele; Araujo Júnior, Edward

    2015-04-01

    Rapid prototyping is becoming a fast-growing and valuable technique for physical models in case of congenital anomalies. Manufacturing models are generally built from three-dimensional (3D) ultrasound, computed tomography, and fetal magnetic resonance imaging (MRI) scan data. Physical prototype has demonstrated to be clinically of value in case of complex fetal malformations and may improve antenatal management especially in cases of craniosynostosis, orofacial clefts, and giant epignathus. In addition, it may enhance parental bonding in visually impaired parents and have didactic value in teaching program. Hereby, the first 3D physical model from 3D ultrasound and MRI scan data reconstruction of lumbosacral myelomeningocele in a third trimester fetus affected by Chiari II malformation is reported.

  5. Diagnostic Accuracy of Ultrasound B scan using 10 MHz linear probe in ocular trauma;results from a high burden country

    PubMed Central

    Shazlee, Muhammad Kashif; Ali, Muhammad; SaadAhmed, Muhammad; Hussain, Ammad; Hameed, Kamran; Lutfi, Irfan Amjad; Khan, Muhammad Tahir

    2016-01-01

    Objective: To study the diagnostic accuracy of Ultrasound B scan using 10 MHz linear probe in ocular trauma. Methods: A total of 61 patients with 63 ocular injuries were assessed during July 2013 to January 2014. All patients were referred to the department of Radiology from Emergency Room since adequate clinical assessment of the fundus was impossible because of the presence of opaque ocular media. Based on radiological diagnosis, the patients were provided treatment (surgical or medical). Clinical diagnosis was confirmed during surgical procedures or clinical follow-up. Results: A total of 63 ocular injuries were examined in 61 patients. The overall sensitivity was 91.5%, Specificity was 98.87%, Positive predictive value was 87.62 and Negative predictive value was 99%. Conclusion: Ultrasound B-scan is a sensitive, non invasive and rapid way of assessing intraocular damage caused by blunt or penetrating eye injuries. PMID:27182245

  6. Development and definition of a simplified scanning procedure and scoring method for Haemophilia Early Arthropathy Detection with Ultrasound (HEAD-US).

    PubMed

    Martinoli, Carlo; Della Casa Alberighi, Ornella; Di Minno, Giovanni; Graziano, Ermelinda; Molinari, Angelo Claudio; Pasta, Gianluigi; Russo, Giuseppe; Santagostino, Elena; Tagliaferri, Annarita; Tagliafico, Alberto; Morfini, Massimo

    2013-06-01

    The aim of this study was to develop a simplified ultrasound scanning procedure and scoring method, named Haemophilia Early Arthropathy Detection with UltraSound [HEAD-US], to evaluate joints of patients with haemophilic arthropathy. After an initial consensus-based process involving a multidisciplinary panel of experts, three comprehensive and evidence-based US scanning procedures to image the elbow, knee and ankle were established with the aim to increase sensitivity in detection of early signs of joint involvement while keeping the technique easy and quick to perform. Each procedure included systematic evaluation of synovial recesses and selection of a single osteochondral surface for damage analysis. Based on expert consensus, a simplified scoring system based on an additive scale was created to define the joint status and, in perspective, to offer a tool to evaluate disease progression and monitor the result of treatment in follow-up studies.

  7. Proper orthogonal decomposition analysis of scanning laser Doppler vibrometer measurements of plaster status at the U.S. Capitol

    NASA Astrophysics Data System (ADS)

    Vignola, Joseph F.; Bucaro, Joseph A.; Tressler, James F.; Ellingston, Damon; Kurdila, Andrew J.; Adams, George; Marchetti, Barbara; Agnani, Alexia; Esposito, Enrico; Tomasini, Enrico P.

    2004-06-01

    A large-scale survey (~700 m2) of frescos and wall paintings was undertaken in the U.S. Capitol Building in Washington, D.C. to identify regions that may need structural repair due to detachment, delamination, or other defects. The survey encompassed eight pre-selected spaces including: Brumidi's first work at the Capitol building in the House Appropriations Committee room; the Parliamentarian's office; the House Speaker's office; the Senate Reception room; the President's Room; and three areas of the Brumidi Corridors. Roughly 60% of the area surveyed was domed or vaulted ceilings, the rest being walls. Approximately 250 scans were done ranging in size from 1 to 4 m2. The typical mesh density was 400 scan points per square meter. A common approach for post-processing time series called Proper Orthogonal Decomposition, or POD, was adapted to frequency-domain data in order to extract the essential features of the structure. We present a POD analysis for one of these panels, pinpointing regions that have experienced severe substructural degradation.

  8. Assessment of visual quality and spatial accuracy of fast anisotropic diffusion and scan conversion algorithms for real-time three-dimensional spherical ultrasound

    NASA Astrophysics Data System (ADS)

    Duan, Qi; Angelini, Elsa D.; Laine, Andrew

    2004-04-01

    Three-dimensional ultrasound machines based on matrix phased-array transducers are gaining predominance for real-time dynamic screening in cardiac and obstetric practice. These transducers array acquire three-dimensional data in spherical coordinates along lines tiled in azimuth and elevation angles at incremental depth. This study aims at evaluating fast filtering and scan conversion algorithms applied in the spherical domain prior to visualization into Cartesian coordinates for visual quality and spatial measurement accuracy. Fast 3d scan conversion algorithms were implemented and with different order interpolation kernels. Downsizing and smoothing of sampling artifacts were integrated in the scan conversion process. In addition, a denoising scheme for spherical coordinate data with 3d anisotropic diffusion was implemented and applied prior to scan conversion to improve image quality. Reconstruction results under different parameter settings, such as different interpolation kernels, scaling factor, smoothing options, and denoising, are reported. Image quality was evaluated on several data sets via visual inspections and measurements of cylinder objects dimensions. Error measurements of the cylinder's radius, reported in this paper, show that the proposed fast scan conversion algorithm can correctly reconstruct three-dimensional ultrasound in Cartesian coordinates under tuned parameter settings. Denoising via three-dimensional anisotropic diffusion was able to greatly improve the quality of resampled data without affecting the accuracy of spatial information after the modification of the introduction of a variable gradient threshold parameter.

  9. Children's (Pediatric) Abdominal Ultrasound Imaging

    MedlinePlus

    ... waves. Ultrasound imaging, also called ultrasound scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ...

  10. Ultrasound of the Thyroid Gland

    MedlinePlus

    ... waves. Ultrasound imaging, also called ultrasound scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ...

  11. Multiband superconductivity in 2 H -NbSe2 probed by Doppler-modulated scanning tunneling spectroscopy

    NASA Astrophysics Data System (ADS)

    Fridman, I.; Kloc, C.; Petrovic, C.; Wei, J. Y. T.

    Cooper pairing in multiband superconductors can involve carriers from bands having different dimensionalities, and the interband coupling can provide for novel pairing interactions. In addition to MgB2, recent experiments on 2 H -NbSe2 have studied the Fermi surface topology using angle- and temperature-dependent scanning tunneling spectroscopy. We present another novel method for probing multiband pairing: using a field-induced diamagnetic supercurrent, applied along different crystal axes, to perturb the quasiparticle density-of-states spectrum. By measuring the evolution of the quasiparticle spectrum under finite superfluid momentum, we characterize the pairing gaps and gap anisotropies. This approach is demonstrated on 2 H -NbSe2 at 300 mK with a magnetic field of up to 9 T applied in the ab -plane. The STM measurements revealed unambiguous evidence for multiband pairing, and evidence for a novel transition of the in-plane vortex lattice. We discuss the characteristics of this transition in light of data from other probes Work supported by NSERC, CFI/OIT, CIFAR, U.S. DOE and Brookhaven Science Associates (No. DE-AC02-98CH10886).

  12. Feasibility of Concurrent Treatment with the Scanning Ultrasound Reflector Linear Array System (SURLAS) and the Helical Tomotherapy System

    PubMed Central

    Peñagarícano, José A.; Moros, Eduardo; Novák, Petr; Yan, Yulong; Corry, Peter

    2010-01-01

    Purpose To evaluate the feasibility of concurrent treatment with the Scanning Ultrasound Reflector Linear Array System (SURLAS) and helical tomotherapy (HT) intensity modulated radiation therapy (IMRT). Methods The SURLAS was placed on a RANDO phantom simulating a patient with superficial or deep recurrent breast cancer. A Megavoltage CT (MVCT) of the phantom with and without the SURLAS was obtained in the HT system. MVCT images with the SURLAS were obtained for two configurations: i) with the SURLAS' long axis parallel and ii) perpendicular to the longitudinal axis of the phantom. The MVCT simulation data set was then transferred to a radiation therapy planning station. Organs at risk (OAR) were contoured including the lungs, heart, abdomen and spinal cord. The metallic parts of the SURLAS were contoured as well and constraints were assigned to completely or directionally block radiation through them. The MVCT-simulation data set and regions of interest (ROI) files were subsequently transferred to the HT planning station. Several HT plans were obtained with optimization parameters that are usually used in the clinic. For comparison purposes, planning was also performed without the SURLAS on the phantom. Results All plans with the SURLAS on the phantom showed adequate dose covering 95% of the planning target volume (PTV D95%), average dose and coefficient of variation of the planning target volume (PTV) dose distribution regardless of the SURLAS' orientation with respect to the RANDO phantom. Likewise, all OAR showed clinically acceptable dose values. Spatial dose distributions and dose-volume histogram (DVH) evaluation showed negligible plan degradation due to the presence of the SURLAS. Beam-on time varied depending on the selected optimization parameters. Conclusion From the perspective of the radiation dosage, concurrent treatment with the SURLAS and HT IMRT is feasible as demonstrated by the obtained clinically acceptable treatment plans. In addition, proper

  13. Microcalcifications in the breast detected by a color Doppler method using twinkling artifacts: some important discussions based on clinical cases and experiments with a new ultrasound modality called multidetector-ultrasonography (MD-US).

    PubMed

    Tsujimoto, Fumio

    2014-01-01

    The twinkling artifact is well known as a color Doppler artifact but it is still an unresolved phenomenon [Rahmouni et al., Radiology 1996;199:269-271 ; Atan et al., Astas Urol Esp 2001;35:396-402; Kamaya et al., AJR 2003;80:215-222]. Many factors affect the appearance of the twinkling artifact, such as the surface roughness of stones creating multiple reflections and a form of intrinsic noise known as clock jitter within the Doppler circuitry of the ultrasound equipment. However, no studies have reported on the twinkling artifact of breast microcalcifications. While considering these premises, I detected microcalcifications in the breast using twinkling artifacts that could not be detected on B-mode imaging. The twinkling artifact is a well-defined but not well-understood phenomenon that may assist in the detection of calcified foci. The phenomenon of the twinkling artifact is discussed here with regard to prospectively and retrospectively studied cases including experiments with a new ultrasound modality called multidetector-ultrasonography (MD-US). MD-US using detectability of the twinkling artifact in microcalcifications of the breast may play an important role in breast screening.

  14. Microcalcifications in the breast detected by a color Doppler method using twinkling artifacts: some important discussions based on clinical cases and experiments with a new ultrasound modality called multidetector-ultrasonography (MD-US).

    PubMed

    Tsujimoto, Fumio

    2014-01-01

    The twinkling artifact is well known as a color Doppler artifact but it is still an unresolved phenomenon [Rahmouni et al., Radiology 1996;199:269-271 ; Atan et al., Astas Urol Esp 2001;35:396-402; Kamaya et al., AJR 2003;80:215-222]. Many factors affect the appearance of the twinkling artifact, such as the surface roughness of stones creating multiple reflections and a form of intrinsic noise known as clock jitter within the Doppler circuitry of the ultrasound equipment. However, no studies have reported on the twinkling artifact of breast microcalcifications. While considering these premises, I detected microcalcifications in the breast using twinkling artifacts that could not be detected on B-mode imaging. The twinkling artifact is a well-defined but not well-understood phenomenon that may assist in the detection of calcified foci. The phenomenon of the twinkling artifact is discussed here with regard to prospectively and retrospectively studied cases including experiments with a new ultrasound modality called multidetector-ultrasonography (MD-US). MD-US using detectability of the twinkling artifact in microcalcifications of the breast may play an important role in breast screening. PMID:27277641

  15. Coordinated Observations of Ion-Neutral Dynamics from a Ground-based Scanning Doppler Imager (SDI) and an Advanced Modular Incoherent Scatter Radar (AMISR)

    NASA Astrophysics Data System (ADS)

    Anderson, C.; Kosch, M.; Nicolls, M. J.; Conde, M. G.

    2011-12-01

    Interactions between the plasma and neutral components of the upper atmosphere result in a diverse set of phenomena that occur over a wide range of spatial and temporal scales. Investigating these interactions requires essentially simultaneous measurements of (spatially resolved) ion and neutral parameters at a time resolution comparable to the time-scales of the underlying driving forces. Two instruments that are ideally suited to such investigations are the Scanning Doppler Imager (SDI) and the Advanced Modular Incoherent Scatter Radar (AMISR). The SDI is capable of resolving small-scale neutral horizontal flow structures and temperature fields across a wide field-of-view, with a temporal resolution of around 4 minutes. The AMISR allows for 'volumetric' ionospheric imaging by sampling along multiple range resolved beams simultaneously, with integration times at least comparable to the SDI. Here we present initial results from a campaign of coordinated observations between an AMISR and SDI located at Poker Flat Research Range in Alaska. This study focuses on the observed signatures of ion-neutral coupling at E and F-region altitudes, in particular the directly measured local ion-neutral velocity difference (required for calculating frictional heating rates) and estimates of the ion-neutral collision frequency from measurements taken along the local geomagnetic field-aligned direction. These observations are placed in the context of the large-scale neutral and ion flows.

  16. Characterization of sub-cloud vertical velocity distributions and precipitation-driven outflow dynamics using a ship-based, scanning Doppler lidar during VOCALS-Rex

    NASA Astrophysics Data System (ADS)

    Brewer, A.; Feingold, G.; Tucker, S. C.; Covert, D. S.; Hardesty, R.

    2010-12-01

    During the VOCALS Regional Experiment NOAA's High Resolution Doppler Lidar (HRDL) operated from the RV Ronald H. Brown and made continuous measurements of sub-cloud horizontal and vertical wind speed and aerosol backscatter signal strength. We will present averaged profiles of vertical velocity distributions and turbulence parameters, stratified by a range of conditions including diurnal variation, precipitation, and distance from shore. The results point to a strong diurnal dependence in the strength of turbulence with nighttime conditions exhibiting stronger subcloud variance. Skewness shows less diurnal sensitivity with a trend towards more negative skewness near cloud base. Combining HRDL’s scanning horizontal wind speed measurements with other ship based in-situ and remote sensing measurements, we investigate the dynamics of precipitation-driven outflows and their impact on surface thermodynamic and aerosol properties. Using a sample of over 150 airmass transitions over the course of the 5 week deployment, we observed that warmer outflow air is typically drier, has less aerosol scattering and tends to have higher ozone concentrations (indicating the transport of air from above the boundary layer top). Transitions to cooler air are generally moister, have more aerosol scattering and show no significant change in ozone concentration. We will present animations of combined lidar/radar/GOES imagery that were used to facilitate visualization and interpretation of the dynamics of the outflows.

  17. Ultrasound pregnancy

    MedlinePlus

    Pregnancy sonogram; Obstetric ultrasonography; Obstetric sonogram; Ultrasound - pregnancy; IUGR - ultrasound; Intrauterine growth - ultrasound; Polyhydramnios - ultrasound; Oligohydramnios - ultrasound; Placenta previa - ultrasound; Multiple ...

  18. Assessment of trabecular bone quality in human cadaver calcaneus using scanning confocal ultrasound and dual x-ray absorptiometry (DEXA) measurements

    NASA Astrophysics Data System (ADS)

    Qin, Yixian; Xia, Yi; Lin, Wei; Rubin, Clinton; Gruber, Barry

    2004-10-01

    Microgravity and aging induced bone loss is a critical skeleton complication, occurring particularly in the weight-supporting skeleton, which leads to osteoporosis and fracture. Advents in quantitative ultrasound (QUS) provide a unique method for evaluating bone strength and density. Using a newly developed scanning confocal acoustic diagnostic (SCAD) system, QUS assessment for bone quality in the real body region was evaluated. A total of 19 human cadaver calcanei, age 66 to 97 years old, were tested by both SCAD and nonscan mode. The scanning region covered an approximate 40×40 mm2 with 0.5 mm resolution. Broadband ultrasound attenuation (BUA, dB/MHz), energy attenuation (ATT, dB), and ultrasound velocity (UV, m/s) were measured. The QUS properties were then correlated to the bone mineral density (BMD) measured by DEXA. Correlations between BMD and QUS parameters were significantly improved by using SCAD as compared to nonscan mode, yielding correlations between BMD and SCAD QUS parameters as R=0.82 (BUA), and R=0.86 (est. BMD). It is suggested that SCAD is feasible for in vivo bone quality mapping. It can be potentially used for monitoring instant changes of bone strength and density. [Work supported by the National Space Biomedical Research Institute (TD00207), and New York Center for Biotechnology.

  19. 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 ...

  20. Evaluation of a pulsed ultrasonic Doppler flowmeter

    NASA Technical Reports Server (NTRS)

    Wells, M. K.

    1973-01-01

    The in vivo application of the pulsed ultrasound Doppler velocity meter (PUDVM) for measuring arterial velocity waveforms is reported. In particular, the performance of the PUDVM is compared with a hot film anemometer of proven accuracy.

  1. The ScanTrainer obstetrics and gynaecology ultrasound virtual reality training simulator: A cost model to determine the cost viability of replacing clinical training with simulation training

    PubMed Central

    Ray, AF

    2015-01-01

    The aim of this study was to produce an economic cost model comparing the use of the Medaphor ScanTrainer virtual reality training simulator for obstetrics and gynaecology ultrasound to achieve basic competence, with the traditional training method. A literature search and survey of expert opinion were used to identify resources used in training. An executable model was produced in Excel. The model showed a cost saving for a clinic using the ScanTrainer of £7114 per annum. The uncertainties of the model were explored and it was found to be robust. Threshold values for the key drivers of the model were identified. Using the ScanTrainer is cost saving for clinics with at least two trainees per year to train, if it would take at least six lists to train them using the traditional training method and if a traditional training list has at least two fewer patients than a standard list. PMID:27433245

  2. Comparison of transverse and longitudinal real-time ultrasound scans for prediction of lean cut yields and fat-free lean content in live pigs.

    PubMed

    Cisneros, F; Ellis, M; Miller, K D; Novakofski, J; Wilson, E R; McKeith, F K

    1996-11-01

    Live animal real-time ultrasound scans and carcass measures were taken on 80 pigs comprising two sexes (42 barrows; 38 gilts) and two halothane genotypes (40 carriers and 40 negatives) that were slaughtered between 108 and 148 kg live weight. Transverse scans (TRUS), at right angles to the midline, were taken on right (RS) and left (LS) sides at the last rib. Longitudinal scans (LON) were taken 6.5 cm off the midline immediately anterior (ANT) and posterior (PST) to the last rib on both the RS and LS. Longissimus muscle depth and area and backfat thickness over the longissimus muscle were measured on TRUS. Backfat thickness and longissimus muscle depth were measured at each end of the LON. Backfat thickness and longissimus muscle measurements were taken at the 10th and last rib on the RS of the carcass. Carcasses were fabricated using standard techniques to establish lean cut yields and carcass soft tissue was chemically analyzed to determine fat-free lean contents. Stepwise regression analysis was performed to develop equations to predict the weights and percentages of lean cuts and fat-free lean. Fat and muscle measures taken from ultrasound scans were generally less accurate than last rib carcass measures at predicting composition. There was little difference in R2 for equations based on either TRUS or ANT/LON; however, PST/LON, generally, were less accurate than ANT/LON. Combining measurements from more than one scan gave little improvement in R2 compared with the best single scan. Estimates of sex bias for carcass composition prediction were small. Halothane genotype and carcass lean content biases were detected; equations derived from the pooled data tended to overestimate the lean content of negative pigs and fatter carcasses and underestimate the lean content of carrier animals and leaner carcasses.

  3. Distortion of thermospheric air masses by horizontal neutral winds over Poker Flat Alaska measured using an all-sky scanning Doppler imager

    NASA Astrophysics Data System (ADS)

    Dhadly, M. S.; Conde, M.

    2016-01-01

    An air mass transported by a wind field will become distorted over time by any gradients present in the wind field. To study this effect in Earth's thermosphere, we examine the behavior of a simple parameter that we describe here as the "distortion gradient." It incorporates all of the wind field's departures from uniformity and is thus capable of representing all contributions to the distortion or mixing of air masses. The distortion gradient is defined such that it is always positive, so averaging over time and/or space does not suppress small-scale features. Conventional gradients, by contrast, are signed quantities that would often average to zero. To analyze the climatological behavior of this distortion gradient, we used three years (2010, 2011, and 2012) of thermospheric F region wind observations from a high-latitude ground-based all-sky wavelength scanning Doppler Fabry-Perot interferometer located at Poker Flat Alaska. Climatological averaging of the distortion gradient allowed us to investigate its diurnal and seasonal (annual) behaviors at our observing location. Distortion was observed to be higher before local magnetic midnight and to be seasonally dependent. While maximum distortion occurred before local magnetic midnight under all geomagnetic conditions, the peak distortion occurred earlier under moderate geomagnetic conditions as compared to the quiet geomagnetic conditions and even earlier still when geomagnetic conditions were active. Peak distortion was stronger and appeared earlier when interplanetary magnetic field (IMF) was southward compared to northward. By contrast, we could not resolve any time-shift effect due to the IMF component tangential to Earth's orbit.

  4. The clinical use of contrast-enhanced ultrasound in the kidney.

    PubMed

    Tenant, Sean C; Gutteridge, Catherine M

    2016-05-01

    Traditional B-Mode and Doppler sonography have been the stalwart of renal tract imaging for many years, and indeed, are in daily use in most centres as the modality of choice for the initial assessment of renal pathology. However, traditional ultrasound scanning can be limited in its ability to accurately characterise renal pathology, and can be inaccurate at determining benign from malignant lesions. Contrast-enhanced ultrasound conveys many benefits, being safe (especially in patients with renal dysfunction), does not require the use of ionising radiation, is quick and relatively cheap and can help to establish whether a focal renal lesion is sinister. Furthermore, it is our experience that contrast-enhanced ultrasound is not a difficult technique to master for the experienced ultrasound practitioner. In this article, we discuss the technique, interpretation and value of contrast-enhanced ultrasound in renal imaging, and describe how we use it in our practice.

  5. Ultrasonic Doppler Modes

    NASA Astrophysics Data System (ADS)

    Tortoli, Piero; Fidanzati, Paolo; Luca, Bassi

    Any US equipment includes Doppler facilities capable of providing information about moving structures inside the human body. In most cases, the primary interest is in the investigation of blood flow dynamics, since this may be helpful for early diagnosis of cardiovascular diseases. However, there is also an increasing interest in tracking the movements of human tissues, since such movements can give an indirect evaluation of their elastic properties, which are valuable indicators of the possible presence of pathologies. This paper aims at presenting an overview of the different ways in which the Doppler technique has been developed and used in medical ultrasound (US), from early continuous wave (CW) systems to advanced pulsed wave (PW) colour-Doppler equipment. In particular, the most important technical features and clinical applications of CW, single-gate PW, multi-gate PW and flow-imaging systems are reviewed. The main signal processing approaches used for detection of Doppler frequencies are described, including time-domain and frequency-domain (spectral) methods, as well as novel strategies like, e.g., harmonic Doppler mode, which have been recently introduced to exploit the benefits of US contrast agents.

  6. Trauma Ultrasound.

    PubMed

    Wongwaisayawan, Sirote; Suwannanon, Ruedeekorn; Prachanukool, Thidathit; Sricharoen, Pungkava; Saksobhavivat, Nitima; Kaewlai, Rathachai

    2015-10-01

    Ultrasound plays a pivotal role in the evaluation of acute trauma patients through the use of multi-site scanning encompassing abdominal, cardiothoracic, vascular and skeletal scans. In a high-speed polytrauma setting, because exsanguinations are the primary cause of trauma morbidity and mortality, ultrasound is used for quick and accurate detection of hemorrhages in the pericardial, pleural, and peritoneal cavities during the primary Advanced Trauma Life Support (ATLS) survey. Volume status can be assessed non-invasively with ultrasound of the inferior vena cava (IVC), which is a useful tool in the initial phase and follow-up evaluations. Pneumothorax can also be quickly detected with ultrasound. During the secondary survey and in patients sustaining low-speed or localized trauma, ultrasound can be used to help detect abdominal organ injuries. This is particularly helpful in patients in whom hemoperitoneum is not identified on an initial scan because findings of organ injuries will expedite the next test, often computed tomography (CT). Moreover, ultrasound can assist in detection of fractures easily obscured on radiography, such as rib and sternal fractures.

  7. A 1 kHz A-scan rate pump-probe laser-ultrasound system for robust inspection of composites.

    PubMed

    Pelivanov, Ivan; Shtokolov, Alex; Wei, Chen-Wei; O'Donnell, Matthew

    2015-09-01

    We recently built a fiber-optic laser-ultrasound (LU) scanner for nondestructive evaluation (NDE) of aircraft composites and demonstrated its greatly improved sensitivity and stability compared with current noncontact systems. It is also very attractive in terms of cost, stability to environmental noise and surface roughness, simplicity in adjustment, footprint, and flexibility. A new type of a balanced fiber-optic Sagnac interferometer is a key component of this all-optical LU pump-probe system. Very high A-scan rates can be achieved because no reference arm or stabilization feedback are needed. Here, we demonstrate LU system performance at 1000 A-scans/s combined with a fast 2-D translator operating at a scanning speed of 100 mm/s with a peak acceleration of 10 m/s(2) in both lateral directions to produce parallel B-scans at high rates. The fast scanning strategy is described in detail. The sensitivity of this system, in terms of noise equivalent pressure, was further improved to be only 8.3 dB above the Nyquist thermal noise limit. To our knowledge, this is the best reported sensitivity for a noncontact ultrasonic detector of this dimension used to inspect aircraft composites. PMID:26415130

  8. A 1 kHz A-scan rate pump-probe laser-ultrasound system for robust inspection of composites.

    PubMed

    Pelivanov, Ivan; Shtokolov, Alex; Wei, Chen-Wei; O'Donnell, Matthew

    2015-09-01

    We recently built a fiber-optic laser-ultrasound (LU) scanner for nondestructive evaluation (NDE) of aircraft composites and demonstrated its greatly improved sensitivity and stability compared with current noncontact systems. It is also very attractive in terms of cost, stability to environmental noise and surface roughness, simplicity in adjustment, footprint, and flexibility. A new type of a balanced fiber-optic Sagnac interferometer is a key component of this all-optical LU pump-probe system. Very high A-scan rates can be achieved because no reference arm or stabilization feedback are needed. Here, we demonstrate LU system performance at 1000 A-scans/s combined with a fast 2-D translator operating at a scanning speed of 100 mm/s with a peak acceleration of 10 m/s(2) in both lateral directions to produce parallel B-scans at high rates. The fast scanning strategy is described in detail. The sensitivity of this system, in terms of noise equivalent pressure, was further improved to be only 8.3 dB above the Nyquist thermal noise limit. To our knowledge, this is the best reported sensitivity for a noncontact ultrasonic detector of this dimension used to inspect aircraft composites.

  9. Ultrasound diagnosis of bilateral cataracts in a fetus with possible cerebro-ocular congential muscular dystrophy during the routine second trimester anomaly scan.

    PubMed

    Drought, Alexandra; Wimalasundera, Ruwan; Holder, Susan

    2015-08-01

    The finding of bilateral congenital cataracts in the fetus is rare. We report bilateral congenital cataracts detected during the routine second trimester anomaly scan, which subsequently were found to be associated with other congenital anomalies and the parents opted for a termination of pregnancy. At post-mortem, Muscle-Eye Brain disease or Walker-Warburg Syndrome was considered likely, which are autosomal recessive congenital muscular dystrophy disorders associated with cerebral, cerebellar, muscle and eye anomalies. On ultrasound, bilateral cataracts appear as echogenic, solid areas within the fetal orbits. The examination of the fetal face and orbits plays an important role in confirming fetal well-being antenatally. We propose that it should become a routine part of the structural survey of fetal anatomy during the obstetric anomaly scan. This is especially important in pregnancies previously affected by fetal cataracts or pregnancies at risk of rare genetic syndromes. PMID:27433255

  10. Ultrasound diagnosis of bilateral cataracts in a fetus with possible cerebro-ocular congential muscular dystrophy during the routine second trimester anomaly scan.

    PubMed

    Drought, Alexandra; Wimalasundera, Ruwan; Holder, Susan

    2015-08-01

    The finding of bilateral congenital cataracts in the fetus is rare. We report bilateral congenital cataracts detected during the routine second trimester anomaly scan, which subsequently were found to be associated with other congenital anomalies and the parents opted for a termination of pregnancy. At post-mortem, Muscle-Eye Brain disease or Walker-Warburg Syndrome was considered likely, which are autosomal recessive congenital muscular dystrophy disorders associated with cerebral, cerebellar, muscle and eye anomalies. On ultrasound, bilateral cataracts appear as echogenic, solid areas within the fetal orbits. The examination of the fetal face and orbits plays an important role in confirming fetal well-being antenatally. We propose that it should become a routine part of the structural survey of fetal anatomy during the obstetric anomaly scan. This is especially important in pregnancies previously affected by fetal cataracts or pregnancies at risk of rare genetic syndromes.

  11. Doppler echocardiography in stress testing.

    PubMed

    Teague, S M

    1991-06-01

    Doppler ultrasound may have a role in the stress testing laboratory for the identification of patients with coronary disease through the assessment of dynamic ventricular systolic function. Quantitative systolic ejection phase indexes of maximal acceleration, peak velocity, and volume of blood ejected from the left ventricle can be obtained in the exercising patient. Trials comparing stress Doppler ultrasound with ST-segment changes, gated blood pool radionuclide or echocardiographic studies of ejection fraction or wall motion abnormality, and thallium scintigraphic perfusion defects have returned comparable or better sensitivity and specificity referencing coronary angiography. Graded treadmill exercise, stationary bicycle exercise, and pharmacological stress (dipyridamole) have been used. The normal Doppler stress response is a near linear increase in peak ejection velocity with increasing cardiac work, as reflected in heart rate. Patients with coronary artery disease show blunted augmentation of Doppler ejection dynamics between rest and peak stress, and the degree of blunting appears to be proportional to the anatomic extent of coronary disease and the magnitude of ventricular perfusion and performance impairment. Stress Doppler ultrasound achieves diagnostic power for coronary disease with ultrasonic technology, inexpensive equipment, without ionizing radiation, and few personnel.

  12. Ultrasonic colour Doppler imaging

    PubMed Central

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

    2011-01-01

    Ultrasonic colour Doppler is an imaging technique that combines anatomical information derived using ultrasonic pulse-echo techniques with velocity information derived using ultrasonic Doppler techniques to generate colour-coded maps of tissue velocity superimposed on grey-scale images of tissue anatomy. The most common use of the technique is to image the movement of blood through the heart, arteries and veins, but it may also be used to image the motion of solid tissues such as the heart walls. Colour Doppler imaging is now provided on almost all commercial ultrasound machines, and has been found to be of great value in assessing blood flow in many clinical conditions. Although the method for obtaining the velocity information is in many ways similar to the method for obtaining the anatomical information, it is technically more demanding for a number of reasons. It also has a number of weaknesses, perhaps the greatest being that in conventional systems, the velocities measured and thus displayed are the components of the flow velocity directly towards or away from the transducer, while ideally the method would give information about the magnitude and direction of the three-dimensional flow vectors. This review briefly introduces the principles behind colour Doppler imaging and describes some clinical applications. It then describes the basic components of conventional colour Doppler systems and the methods used to derive velocity information from the ultrasound signal. Next, a number of new techniques that seek to overcome the vector problem mentioned above are described. Finally, some examples of vector velocity images are presented. PMID:22866227

  13. Effectiveness of evaluating tumor vascularization using 3D power Doppler ultrasound with high-definition flow technology in the prediction of the response to neoadjuvant chemotherapy for T2 breast cancer: a preliminary report

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

    The aim of this study was to evaluate the effectiveness of advanced ultrasound (US) imaging of vascular flow and morphological features in the prediction of a pathologic complete response (pCR) and a partial response (PR) to neoadjuvant chemotherapy for T2 breast cancer. Twenty-nine consecutive patients with T2 breast cancer treated with six courses of anthracycline-based neoadjuvant chemotherapy were enrolled. Three-dimensional (3D) power Doppler US with high-definition flow (HDF) technology was used to investigate the blood flow in and morphological features of the tumors. Six vascularity quantization features, three morphological features, and two vascular direction features were selected and extracted from the US images. A support vector machine was used to evaluate the changes in vascularity after neoadjuvant chemotherapy, and pCR and PR were predicted on the basis of these changes. The most accurate prediction of pCR was achieved after the first chemotherapy cycle, with an accuracy of 93.1% and a specificity of 85.5%, while that of a PR was achieved after the second cycle, with an accuracy of 79.31% and a specificity of 72.22%. Vascularity data can be useful to predict the effects of neoadjuvant chemotherapy. Determination of changes in vascularity after neoadjuvant chemotherapy using 3D power Doppler US with HDF can generate accurate predictions of the patient response, facilitating early decision-making.

  14. Three-dimensional ultrasound imaging of the vasculature.

    PubMed

    Fenster, A; Lee, D; Sherebrin, S; Rankin, R; Downey, D

    1998-02-01

    With conventional ultrasonography, the diagnostician must view a series of two-dimensional images in order to form a mental impression of the three-dimensional anatomy, an efficient and time consuming practice prone to operator variability, which may cause variable or even incorrect diagnoses. Also, a conventional two-dimensional ultrasound image represents a thin slice of the patients anatomy at a single location and orientation, which is difficult to reproduce at a later time. These factors make conventional ultrasonography non-optimal for prospective or follow-up studies. Our efforts have focused on overcoming these deficiencies by developing three-dimensional ultrasound imaging techniques that are capable of acquiring B-mode, colour Doppler and power Doppler images of the vasculature, by using a conventional ultrasound system to acquire a series of two-dimensional images and then mathematically reconstructing them into a single three-dimensional image, which may then be viewed interactively on an inexpensive desktop computer. We report here on two approaches: (1) free-hand scanning, in which a magnetic positioning device is attached to the ultrasound transducer to record the position and orientation of each two-dimensional image needed for the three-dimensional image reconstruction; and (2) mechanical scanning, in which a motor-driven assembly is used to translate the transducer linearly across the neck, yielding a set of uniformly-spaced parallel two-dimensional images.

  15. Real Time Fast Ultrasound Imaging Technology and Possible Applications

    NASA Astrophysics Data System (ADS)

    Cruza, J. F.; Perez, M.; Moreno, J. M.; Fritsch, C.

    In this work, a novel hardware architecture for fast ultrasound imaging based on FPGA devices is proposed. A key difference over other approaches is the unlimited scalability in terms of active channels without performance losses. Acquisition and processing tasks share the same hardware, eliminating communication bottlenecks with smaller size and power losses. These features make this system suitable to implement the most demanding imaging applications, like 3D Phased Array, Total Focusing Method, Vector Doppler, Image Compounding, High Speed Part Scanning and advanced elastographic techniques. A single medium sized FPGA allows beamforming up to 200 scan lines simultaneously, which is enough to perform most of the above mentioned applications in strict real time.

  16. Photoacoustic Doppler Effect from Flowing Small Light-Absorbing Particles

    NASA Astrophysics Data System (ADS)

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

    2007-11-01

    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.

  17. Photoacoustic Doppler effect from flowing small light-absorbing particles.

    PubMed

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

    2007-11-01

    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.

  18. Role of B-scan ocular ultrasound as an adjuvant for the clinical assessment of eyeball diseases: a pictorial essay.

    PubMed

    Dessì, Gerardo; Lahuerta, Eduardo Ferrer; Puce, Fabrizio Giorgio; Mendoza, Luis Humberto Ros; Stefanini, Teseo; Rosenberg, Ilan; Del Prato, Alberto; Perinetti, Michela; Villa, Alessandro

    2015-09-01

    We report our experience in B-mode ocular ultrasonography, focusing on its contribution when the clinical examination proves to be difficult, mainly due to the existence of intraocular opacities of the ocular fundus or diagnostic doubts. We revise the ocular ultrasound technique, its indications and contraindications, comparing to the other imaging techniques. In our experience ultrasonography revealed pathological findings which confirmed the clinical suspicion in most of cases or provide additional information. With understanding of the indications for ultrasonography and proper examination technique, one can gather a vast amount of information not possible with clinical examination alone.

  19. Additive and epistatic genome-wide association for growth and ultrasound scan measures of carcass-related traits in Brahman cattle.

    PubMed

    Ali, A A; Khatkar, M S; Kadarmideen, H N; Thomson, P C

    2015-04-01

    Genome-wide association studies are routinely used to identify genomic regions associated with traits of interest. However, this ignores an important class of genomic associations, that of epistatic interactions. A genome-wide interaction analysis between single nucleotide polymorphisms (SNPs) using highly dense markers can detect epistatic interactions, but is a difficult task due to multiple testing and computational demand. However, It is important for revealing complex trait heredity. This study considers analytical methods that detect statistical interactions between pairs of loci. We investigated a three-stage modelling procedure: (i) a model without the SNP to estimate the variance components; (ii) a model with the SNP using variance component estimates from (i), thus avoiding iteration; and (iii) using the significant SNPs from (ii) for genome-wide epistasis analysis. We fitted these three-stage models to field data for growth and ultrasound measures for subcutaneous fat thickness in Brahman cattle. The study demonstrated the usefulness of modelling epistasis in the analysis of complex traits as it revealed extra sources of genetic variation and identified potential candidate genes affecting the concentration of insulin-like growth factor-1 and ultrasound scan measure of fat depth traits. Information about epistasis can add to our understanding of the complex genetic networks that form the fundamental basis of biological systems. PMID:25754883

  20. Scanning Ultrasound (SUS) Causes No Changes to Neuronal Excitability and Prevents Age-Related Reductions in Hippocampal CA1 Dendritic Structure in Wild-Type Mice

    PubMed Central

    Hatch, Robert John; Leinenga, Gerhard

    2016-01-01

    Scanning ultrasound (SUS) is a noninvasive approach that has recently been shown to ameliorate histopathological changes and restore memory functions in an Alzheimer's disease mouse model. Although no overt neuronal damage was reported, the short- and long-term effects of SUS on neuronal excitability and dendritic tree morphology had not been investigated. To address this, we performed patch-clamp recordings from hippocampal CA1 pyramidal neurons in wild-type mice 2 and 24 hours after a single SUS treatment, and one week and 3 months after six weekly SUS treatments, including sham treatments as controls. In both treatment regimes, no changes in CA1 neuronal excitability were observed in SUS-treated neurons when compared to sham-treated neurons at any time-point. For the multiple treatment groups, we also determined the dendritic morphology and spine densities of the neurons from which we had recorded. The apical trees of sham-treated neurons were reduced at the 3 month time-point when compared to one week; however, surprisingly, no longitudinal change was detected in the apical dendritic trees of SUS-treated neurons. In contrast, the length and complexity of the basal dendritic trees were not affected by SUS treatment at either time-point. The apical dendritic spine densities were reduced, independent of the treatment group, at 3 months compared to one week. Collectively, these data suggest that ultrasound can be employed to prevent an age-associated loss of dendritic structure without impairing neuronal excitability. PMID:27727310

  1. Additive and epistatic genome-wide association for growth and ultrasound scan measures of carcass-related traits in Brahman cattle.

    PubMed

    Ali, A A; Khatkar, M S; Kadarmideen, H N; Thomson, P C

    2015-04-01

    Genome-wide association studies are routinely used to identify genomic regions associated with traits of interest. However, this ignores an important class of genomic associations, that of epistatic interactions. A genome-wide interaction analysis between single nucleotide polymorphisms (SNPs) using highly dense markers can detect epistatic interactions, but is a difficult task due to multiple testing and computational demand. However, It is important for revealing complex trait heredity. This study considers analytical methods that detect statistical interactions between pairs of loci. We investigated a three-stage modelling procedure: (i) a model without the SNP to estimate the variance components; (ii) a model with the SNP using variance component estimates from (i), thus avoiding iteration; and (iii) using the significant SNPs from (ii) for genome-wide epistasis analysis. We fitted these three-stage models to field data for growth and ultrasound measures for subcutaneous fat thickness in Brahman cattle. The study demonstrated the usefulness of modelling epistasis in the analysis of complex traits as it revealed extra sources of genetic variation and identified potential candidate genes affecting the concentration of insulin-like growth factor-1 and ultrasound scan measure of fat depth traits. Information about epistasis can add to our understanding of the complex genetic networks that form the fundamental basis of biological systems.

  2. [Cesarean scar ectopic pregnancy: diagnosis with 2D, three-dimensional (3D) ultrasound and 3D power doppler of a case and review of the literature].

    PubMed

    Pavlova, E; Gunev, D; Diavolov, V; Slavchev, B

    2013-01-01

    Cesarean scar pregnancy is rare type of ectopic pregnancy. It is associated with severe complication if it is not diagnosed early in pregnancy. We present a case of difficult first-trimester diagnosis of Cesarean scar pregnancy. In this paper we discuss the incidence of this condition, the antenatal diagnosis, the prognosis and management and the importance of 2D and 3D ultrasound technique as a diagnostic tool. PMID:24501880

  3. [Ultrasound duplex scanning in the assessment of the effectiveness of gravitation therapy and conservative treatment of patients with atherosclerosis obliterans of the lower extremities].

    PubMed

    Galkin, R A; Makarov, I V; Preobrazhenskaia, N M

    2004-01-01

    Ultrasound duplex scanning was used to compare the results of the treatment of 162 patients suffering from atherosclerosis obliterans of the lower extremities. It is to be noted that 50 patients were administered only gravitation therapy, 72 patients underwent a complex of treatment measures including, in addition to gravitation therapy, physiotherapy and drug treatment, and 40 patients received conservative treatment alone. The assessment criteria were the maximal systolic velocity of blood flow (V(max)), end diastolic mean, velocity (V(min)), mean maximal velocity (V(mean)), volume velocity of blood flow (V(vol)), ankle/brachial index (ABI), and index of regional perfusion (IRP), proposed by us and representing the percent ratio of the volume velocity of blood flow to the minute heart volume (MHV). It has been revealed in the course of the treatment that the best clinical outcome was recorded in patients who received a complex of treatment measures. The use of gravitation therapy alone provided better treatment results as compared to those obtained in patients administered standard conservative therapy. Of all the indicators used, only V(mean), V(vol), ABI and IRP are of the clinical significance. However, the most significant information on the segmental blood flow was obtained on the assessment of the IRP whose values did not depend on the changes in central hemodynamics. In contrast to the ABI, the advantage of the IRP lies in the possibility of blood flow assessment in different segments and arteries of the extremities. So, the use of the quantitative indicators of ultrasound duplex scanning and, first of all, of the IRP, allows an objective evaluation of the segmental blood flow and may serve one of the significant criteria of the treatment effectiveness.

  4. The Effectiveness of Real-Time Feedback with an Audible Pulse: A Preliminary Study in Renal Doppler Ultrasonography

    PubMed Central

    Lee, Min Hee; Lee, Hae Kyung; Choi, Seo-Youn; Yi, Boem Ha

    2016-01-01

    Purpose The effectiveness of real-time feedback using an audible pulse in renal Doppler ultrasonography was evaluated. Methods This study was approved by the institutional review board of our hospital. Written informed consent was provided by all volunteers at enrollment. The 26 healthy volunteers enrolled in this study underwent Doppler ultrasound of both kidneys using audible and inaudible pulses in randomized order and at 1-week intervals. Doppler waveforms were obtained at the interlobar or arcuate arteries using a 2-mm Doppler gate. Each session was considered complete when reproducible waveforms were obtained for 5 s in three predefined regions of the kidney. The scan times needed to obtain waveforms of the right and left kidneys were recorded separately. Measurements were compared using a paired t-test and a two-sample Wilcoxon rank-sum test. Results The total recorded Doppler sonography scan time for each kidney ranged from 33 to 146 s. The mean scan time was 56.83 s (right, 58.19 s; left, 55.46 s) in the audible session and 72.58 s (right, 72.08 s; left, 73.08 s) in the inaudible session. The scan times were significantly shorter in the audible than inaudible session (p<0.001), whereas the difference in the scan times between the right and left kidneys was not significant. The order of the sessions had no effect on the total scan time. Conclusion Real-time feedback using an audible pulse may encourage patient cooperation during breath-holding and can shorten the time needed to perform Doppler ultrasonography. PMID:27685667

  5. Two-dimensional blood flow velocity estimation using ultrasound speckle pattern dependence on scan direction and A-line acquisition velocity.

    PubMed

    Xu, Tiantian; Bashford, Gregory

    2013-05-01

    We have previously investigated the change of apparent lateral speckle size caused by the direction and spatial rate of scanner A-line acquisition (scan velocity). An algorithm which measures the lateral component of blood flow velocity was developed based on the increase in speckle size resulting from relative motion between moving scatterers and the scan velocity. In this paper, the change of the apparent dominant angle of the speckle pattern in a straight vessel was investigated and a new method of two-dimensional blood flow velocity estimation is introduced. Different scan velocities were used for data acquisition from blood flow traveling at an angle relative to the ultrasound beam. The apparent angle of the speckle pattern changes with different scan velocities because of misregistration between the ultrasound beam and scatterers. The apparent angle of the speckle pattern was resolved by line-to-line cross-correlation in the fast-time (axial) direction on a region-of-interest (ROI) in each blood flow image and used to spatially align the ROI. The resulting lateral speckle size within the aligned ROI was calculated. The lateral component of the blood flow is shown to be closest to the scan velocity which gives the maximum speckle size and the apparent angle of speckle pattern collected by this scan velocity is the best estimate for the actual angle of blood flow. These two components produce two-dimensional blood flow velocity estimations. This method was studied through both computer simulation and experiments with a blood flow phantom. Nine scan velocities were used to collect blood flow data with velocities ranging from 33 to 98 cm/s and four beam-to-flow angles. In simulated plug blood flow, the mean bias of angle estimation is below 2% with an average standard deviation of 3.6%. In simulated parabolic blood flow, the angle of blood flow is overestimated because of speckle decorrelation caused by flow gradients and the estimation bias increases with

  6. Doppler echocardiography

    SciTech Connect

    Labovitz, A.J.; Williams, G.A.

    1988-01-01

    The authors are successful in presenting a basic book on clinical quantitative Doppler echocardiography. It is not intended to be a comprehensive text, but it does cover clinical applications in a succinct fashion. Only the more common diseases in the adult are considered. The subjects are presented logically and are easy to comprehend. The illustrations are good, and the book is paperbound. The basic principles of Doppler echocardiography are presented briefly. The book ends with chapters on left ventricular function (stroke volume and cardiac output), congenital heart disease, and color Doppler echo-cardiography. There are numerous references and a good glossary and index.

  7. Laser Doppler flowmetry imaging

    NASA Astrophysics Data System (ADS)

    Nilsson, Gert E.; Wardell, Karin

    1994-02-01

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

  8. Calibration of non-contact ultrasound as an online sensor for wood characterization: Effects of temperature, moisture, and scanning direction

    NASA Astrophysics Data System (ADS)

    Vun, R. Y.; Hoover, K.; Janowiak, J.; Bhardwaj, M.

    2008-01-01

    Numerous handheld moisture meters are available for measuring moisture levels of wood and building materials for a vast range of quality control and moisture diagnosis applications. However, many methods currently available require physical contact of a probe with the test material to operate. The contact requirement of such devices has limited applications for these purposes. There is a tremendous demand for dynamic online quality assessment of in-process materials for moisture content (MC) measurements. In this paper, a non-destructive non-contact ultrasound technology was used to evaluate the effects of increasing temperature in two MC levels and of increasing MC in lumber. The results show that the ultrasonic absolute transmittance and velocity parameters are directly correlated very well (R2≥0.87) with temperature for the two moisture levels in wood. At constant temperature, however, the velocity is inversely correlated with MC. It was also found that the distribution of MC along the length is marginally insignificant to both ultrasonic measurements. The transmittance measurement along the orthogonal thickness direction is insignificant above the fiber saturation MC; similarly, the velocity measurement is marginally insignificant. The study concludes a positive correlation and a good fit for this technology to advance into the development of an automated device for determining wood moisture levels, which will in turn be used to control the dynamics of wood drying/sterilization processes. Further calibration research is recommended to ascertain the constraints and limitations of the technology to specific wood species and dimension.

  9. Comparison between doppler ultrasound resistive index, serum creatinine, and histopathologic changes in patients with kidney transplant dysfunction in early posttransplantation period: A single center study with review of literature.

    PubMed

    Patel, Kajal N; Patel, Nitin A; Gandhi, Shruti P

    2016-05-01

    To determine the relationship between resistive index (RI) measured by Doppler ultrasound, serum creatinine (SCr), and histopathological changes on biopsy during kidney trans- plant dysfunction in early postoperative period, we studied 47 kidney transplant patients; 61% of the patients had acute transplant rejection, 19% had acute tubular necrosis, 4% had calcineurin inhibitor toxicity, 11% had normal morphology in biopsy, and 5% had changes compatible with pyelonephritis. None of the study patients had interstitial fibrosis or tubular atrophy on biopsy. We found that the sensitivity and specificity of RI in diagnosing transplant dysfunction was highly variable depending on the selected cutoff value. Sensitivity of RI decreased and its specificity increased with increasing the RI thresholds. Using an RI threshold of 0.7 resulted in a high sensitivity of 78% at a cost of very low specificity 40%, whereas using an RI threshold of 0.9 resulted in 100% specificity at a cost of very low sensitivity 16%. Acceptable specificity was only achieved at the expense of very low sensitivity, resulting in poor utility of RI as a screening tool for dysfunction. We found that there were no significant differences in the mean RI value between patients with and without biopsy-proven transplant dysfunction. However, we found a significant correlation between SCr value and RI of 0.383, P = 0.007.

  10. Comparison between doppler ultrasound resistive index, serum creatinine, and histopathologic changes in patients with kidney transplant dysfunction in early posttransplantation period: A single center study with review of literature.

    PubMed

    Patel, Kajal N; Patel, Nitin A; Gandhi, Shruti P

    2016-05-01

    To determine the relationship between resistive index (RI) measured by Doppler ultrasound, serum creatinine (SCr), and histopathological changes on biopsy during kidney trans- plant dysfunction in early postoperative period, we studied 47 kidney transplant patients; 61% of the patients had acute transplant rejection, 19% had acute tubular necrosis, 4% had calcineurin inhibitor toxicity, 11% had normal morphology in biopsy, and 5% had changes compatible with pyelonephritis. None of the study patients had interstitial fibrosis or tubular atrophy on biopsy. We found that the sensitivity and specificity of RI in diagnosing transplant dysfunction was highly variable depending on the selected cutoff value. Sensitivity of RI decreased and its specificity increased with increasing the RI thresholds. Using an RI threshold of 0.7 resulted in a high sensitivity of 78% at a cost of very low specificity 40%, whereas using an RI threshold of 0.9 resulted in 100% specificity at a cost of very low sensitivity 16%. Acceptable specificity was only achieved at the expense of very low sensitivity, resulting in poor utility of RI as a screening tool for dysfunction. We found that there were no significant differences in the mean RI value between patients with and without biopsy-proven transplant dysfunction. However, we found a significant correlation between SCr value and RI of 0.383, P = 0.007. PMID:27215246

  11. 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

  12. "Holy scan" or "picture of the baby?" Biomedicalization and stratification in the use of obstetric ultrasound in Rio de Janeiro.

    PubMed

    Chazan, Lilian Krakowski; Faro, Livi F T

    2016-01-01

    Based on ethnographic studies conducted at public and private healthcare facilities in Rio de Janeiro, we argue that the dissemination of (bio)medicalization varies in accordance with the social stratum of the expectant mothers, thereby producing thoroughly distinct fetal and pregnant bodies, as well as different gestational processes. Starting from the basic premise that biomedicalization represents a transformation in the process of medicalization, characterized by the growing incorporation of technoscience into biomedicine, the observed universes displayed different stages in this transformation, consonant with the social stratification of the women who underwent the scans. PMID:27008074

  13. Measurement uncertainty in pulmonary vascular input impedance and characteristic impedance estimated from pulsed-wave Doppler ultrasound and pressure: clinical studies on 57 pediatric patients.

    PubMed

    Tian, Lian; Hunter, Kendall S; Kirby, K Scott; Ivy, D Dunbar; Shandas, Robin

    2010-06-01

    Pulmonary vascular input impedance better characterizes right ventricular (RV) afterload and disease outcomes in pulmonary hypertension compared to the standard clinical diagnostic, pulmonary vascular resistance (PVR). Early efforts to measure impedance were not routine, involving open-chest measurement. Recently, the use of pulsed-wave (PW) Doppler-measured velocity to non-invasively estimate instantaneous flow has made impedance measurement more practical. One critical concern remains with clinical use: the measurement uncertainty, especially since previous studies only incorporated random error. This study utilized data from a large pediatric patient population to comprehensively examine the systematic and random error contributions to the total impedance uncertainty and determined the least error prone methodology to compute impedance from among four different methods. We found that the systematic error contributes greatly to the total uncertainty and that one of the four methods had significantly smaller propagated uncertainty; however, even when this best method is used, the uncertainty can be large for input impedance at high harmonics and for the characteristic impedance modulus. Finally, we found that uncertainty in impedance between normotensive and hypertensive patient groups displays no significant difference. It is concluded that clinical impedance measurement would be most improved by advancements in instrumentation, and the best computation method is proposed for future clinical use of the input impedance.

  14. [Ultrasound imaging in laryngology].

    PubMed

    Zajkowski, Piotr; Białek, Ewa J

    2007-01-01

    Modern ultrasound with high resolution transducers, and sensitive power Doppler and color Doppler modes, and other options, such as panoramic and 3D imaging, allows for detailed imaging of many anatomical structures and pathologic lesions of the head and neck. Only the structures situated in the sonographic acoustic shadow: behind bones, calcified cartilages, stones, and behind organs containing gas (f.e. trachea and larynx) can not be visualized. Ultrasound is widely regarded as the first imaging method in the diseases of the thyroid, salivary glands (parotid gland, submandibular gland and sublingual gland), lymph nodes, muscles, soft tissues of the head and neck, and as an valuable adjunct in some laryngeal pathologies. Real time ultrasound examination allows for dynamic assessment of organs and lesions, lets the examiner check the susceptibility of tumors for pressure, which is inaccessible in other imaging methods. Tumors and congenital lesions, inflammation, abscesses, abnormal lymph nodes, cysts, muscle hypertrophy and posttraumatic conditions may be well evaluated with ultrasound. However, most neck tumors (f.e. in the thyroid, salivary glands, and soft tisses) as well as equivocal lymph nodes demand fine needle aspiration biopsy to determine their benign or malignant nature. This paper presents application of ultrasound examination in the head and neck area including limitations of ultrasound diagnostics in many clinical cases. Data taken from Polish and foreign literature and author's experience are included in this paper.

  15. To assess the intimal thickness, flow velocities, and luminal diameter of carotid arteries using high-resolution B-mode ultrasound doppler imaging

    NASA Astrophysics Data System (ADS)

    Vemuru, Madhuri; Jabbar, Afzal; Chandra, Suman

    2004-04-01

    Carotid imaging is a Gold Standard test that provides useful information about the structure and functions of carotid arteries. Spectral imaging helps to evaluate the vessel and hemodynamic changes. High resolution B-mode imaging has emerged as one of the methods of choice for determining the anatomic extent of atherosclerosis and its progression and for assessing cardiovascular risks. The measurements made with Doppler correlate well with pathologic measurements. Recent prospective studies have clearly demonstrated that these measurements of carotid intimal thickness are potent predictors of Myocardial Infarction and Stroke. This method appears very attractive as it is non-invasive, extremely safe, well accepted by the patient and relatively inexpensive. It can be performed serially and has the advantage of visualizing the arterial wall in contrast to angiographic techniques which provide only an outline of the arterial lumen. Recently, there has been an interest in the clinical use of this technique in making difficult clinical decisions like deciding on preventive therapies. 30 subjects aged 21-60 years and 30 subjects aged 61-85 years of both sexes are selected after doing a baseline study to exclude Hypertension, Diabetes, Obesity and Hyperlipidemia. The carotid arteries were examined for intimal thickening, blood flow velocities and luminal diameter. With aging there is a narrowing of the carotid vessels and significant increase in intimal thickening with a consequent increase in the blood flow velocities. Inter-observer, intra-observer and instrument variations are seen and there is no significant change in the values when the distal flow pattern is considered for measurements. Aging produces major cardiovascular changes including decreased elasticity and compliance of great arteries leading to structural and functional alterations in heart and vessels. With aging there is increased intimal thickness and increased pulse wave velocity which is clearly

  16. Axial ultrasound B-scans of the entire eye with a 20-MHz linear array: correction of crystalline lens phase aberration by applying Fermat's principle.

    PubMed

    Mateo, Tony; Chang, Alexandre; Mofid, Yassine; Pisella, Pierre-Jean; Ossant, Frederic

    2014-11-01

    In ophthalmic ultrasonography the crystalline lens is known to be the main source of phase aberration, causing a significant decrease in resolution and distortion effects on axial B-scans. This paper proposes a computationally efficient method to correct the phase aberration arising from the crystalline lens, including refraction effects using a bending ray tracing approach based on Fermat's principle. This method is used as a basis to perform eye-adapted beamforming (BF), with appropriate focusing delays for a 128-element 20-MHz linear array in both emission and reception. Implementation was achieved on an in-house developed experimental ultrasound scanning device, the ECODERM. The proposed BF was tested in vitro by imaging a wire phantom through an eye phantom consisting of a synthetic gelatin lens anatomically set up in an appropriate liquid (turpentine) to approach the in vivo velocity ratio. Both extremes of accommodation shapes of the human crystalline lens were investigated. The performance of the developed BF was evaluated in relation to that in homogeneous medium and compared to a conventional delay-and-sum (DAS) BF and a second adapted BF which was simplified to ignore the lens refraction. Global expectations provided by our method with the transducer array are reviewed by an analysis quantifying both image quality and spatial fidelity, as well as the detrimental effects of a crystalline lens in conventional reconstruction. Compared to conventional array imaging, the results indicated a two-fold improvement in the lateral resolution, greater sensitivity and a considerable reduction of spatial distortions that were sufficient to envisage reliable biometry directly in B-mode, especially phakometry. PMID:24988589

  17. Assessment of the accuracy of an ultrasound elastography liver scanning system using a PVA-cryogel phantom with optimal acoustic and mechanical properties

    NASA Astrophysics Data System (ADS)

    Cournane, S.; Cannon, L.; Browne, J. E.; Fagan, A. J.

    2010-10-01

    The accuracy of a transient elastography liver-scanning ultrasound system was assessed using a novel application of PVA-cryogel as a tissue-mimicking material with acoustic and shear elasticity properties optimized to best represent those of liver tissue. Although the liver-scanning system has been shown to offer a safer alternative for diagnosing liver cirrhosis through stiffness measurement, as compared to the liver needle biopsy exam, the scanner's accuracy has not been fully established. Young's elastic modulus values of 5-6 wt% PVA-cryogel phantoms, also containing glycerol and 0.3 µm Al2O3 and 3 µm Al2O3, were measured using a 'gold standard' mechanical testing technique and transient elastography. The mechanically measured values and acoustic velocities of the phantoms ranged between 1.6 and 16.1 kPa and 1540 and 1570 m s-1, respectively, mimicking those observed in liver tissue. The values reported by the transient elastography system overestimated Young's elastic modulus values representative of the progressive stages of liver fibrosis by up to 32%. These results were attributed to the relative rather than absolute nature of the measurement arising from the single-point acoustic velocity calibration of the system, rendering the measurements critically dependent on the speed of sound of the sample under investigation. Given the wide range of acoustic velocities which exist in the liver, spanning healthy tissue to cirrhotic pathology, coupled with the system's assumption that the liver is approximately elastic when it is rather highly viscoelastic, care should be exercised when interpreting the results from this system in patient groups.

  18. 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.

  19. Use of A-scan for penetration control during dual-frequency ultrasound thermal therapy of superficial tissues overlaying bone and lung

    NASA Astrophysics Data System (ADS)

    Moros, Eduardo G.; Straube, William L.; Fan, Xiaobing

    1999-05-01

    An ultrasonic system capable of Lateral Power Conformability, Penetration Depth Control (PDC), and the ability to deliver hyperthermia concomitantly with external beam radiation is being developed. PDC is achieved by simultaneously insonating with beams of low (1 MHz) and high (5 MHz) frequency. This paper presents a sono-thermal numerical evaluation of the impact of PDC on thermal dose in the treatment of chest wall volumes. The main goal is to assess the potential advantages of impedance-mismatched interface depth-mapping, using therapy transducers in A-scan mode, to select optimal relative output intensities of the beams as a function of bone and lung depths. Simulation results for a representative chest wall anatomy showed that there exists a strong relationship between optimal relative output intensities and bone/lung depth for maximum thermal dose and minimum muscle-bone interface temperature. Consequently, interface depth-mapping prior to a dual- frequency ultrasound hyperthermia treatment would provide patient-specific data useful for selecting PDC parameters that maximize thermal dose and minimize bone heating.

  20. Searching the perfect ultrasonic classification in assessing carotid artery stenosis: comparison and remarks upon the existing ultrasound criteria.

    PubMed

    Mozzini, Chiara; Roscia, Giuseppe; Casadei, Alder; Cominacini, Luciano

    2016-01-01

    Doppler ultrasound scanning is the first line investigation for quantifying the internal carotid artery stenosis. Nevertheless, the lack of internationally accepted ultrasound criteria for describing the degree of stenosis has contributed to the different and confusing measurements ranges. The use of two different angiographic methods, the North American Symptomatic Carotid Endoarterectomy Study and the European Carotid Surgery Trial was probably the major initial source of confusion in deriving valid and reliable duplex ultrasound criteria worldwide. The consensus proposed in 2003 by the Society of Radiologists in Ultrasound has been a great attempt to create a conformity document, establishing grey scale and Doppler criteria in considering the different degrees of stenosis. According to this attempt, in 2010, the multi-parametric Deutsche Gesellschaft für Ultraschall in der Medizin ultrasound criteria have been proposed with a precise differentiation between main and additional criteria and depicted a different peak systolic velocity (PSV) threshold. In 2012, these criteria have been implemented, focusing on the multi-parametric approach, re-defining the PSV values and clearly introducing the concept of PSV average. Despite these attempts, a wide range of practice patterns still exists, with consistent disparities in patients' care. This paper collects these previous experiences and summarizes their strengths and weaknesses, to give a contribution in the carotid artery stenosis grading standardization using ultrasonic methods. Carotid ultrasound as the only diagnostic tool for the selection of patients for carotid surgery or stenting will be possible only with internationally accepted criteria.

  1. Searching the perfect ultrasonic classification in assessing carotid artery stenosis: comparison and remarks upon the existing ultrasound criteria.

    PubMed

    Mozzini, Chiara; Roscia, Giuseppe; Casadei, Alder; Cominacini, Luciano

    2016-01-01

    Doppler ultrasound scanning is the first line investigation for quantifying the internal carotid artery stenosis. Nevertheless, the lack of internationally accepted ultrasound criteria for describing the degree of stenosis has contributed to the different and confusing measurements ranges. The use of two different angiographic methods, the North American Symptomatic Carotid Endoarterectomy Study and the European Carotid Surgery Trial was probably the major initial source of confusion in deriving valid and reliable duplex ultrasound criteria worldwide. The consensus proposed in 2003 by the Society of Radiologists in Ultrasound has been a great attempt to create a conformity document, establishing grey scale and Doppler criteria in considering the different degrees of stenosis. According to this attempt, in 2010, the multi-parametric Deutsche Gesellschaft für Ultraschall in der Medizin ultrasound criteria have been proposed with a precise differentiation between main and additional criteria and depicted a different peak systolic velocity (PSV) threshold. In 2012, these criteria have been implemented, focusing on the multi-parametric approach, re-defining the PSV values and clearly introducing the concept of PSV average. Despite these attempts, a wide range of practice patterns still exists, with consistent disparities in patients' care. This paper collects these previous experiences and summarizes their strengths and weaknesses, to give a contribution in the carotid artery stenosis grading standardization using ultrasonic methods. Carotid ultrasound as the only diagnostic tool for the selection of patients for carotid surgery or stenting will be possible only with internationally accepted criteria. PMID:27298648

  2. A Cross-Track Cloud-Scanning Dual-Frequency Doppler (C2D2) Radar for the Proposed ACE Mission and Beyond

    NASA Technical Reports Server (NTRS)

    Sadowy, Gregory; Tanelli, Simone; Chamberlain, Neil; Durden, Stephen; Fung, Andy; Sanchez-Barbetty, Mauricio; Thrivikraman, Tushar

    2013-01-01

    The National Resource Council’s Earth Science Decadal Survey” (NRCDS) has identified the Aerosol/Climate/Ecosystems (ACE) Mission as a priority mission for NASA Earth science. The NRC recommended the inclusion of "a cross-track scanning cloud radar with channels at 94 GHz and possibly 34 GHz for measurement of cloud droplet size, glaciation height, and cloud height". Several radar concepts have been proposed that meet some of the requirements of the proposed ACE mission but none have provided scanning capability at both 34 and 94 GHz due to the challenge of constructing scanning antennas at 94 GHz. In this paper, we will describe a radar design that leverages new developments in microwave monolithic integrated circuits (MMICs) and micro-machining to enable an electronically-scanned radar with both Ka-band (35 GHz) and W-band (94-GHz) channels. This system uses a dual-frequency linear active electronically-steered array (AESA) combined with a parabolic cylindrical reflector. This configuration provides a large aperture (3m x 5m) with electronic-steering but is much simpler than a two-dimension AESA of similar size. Still, the W-band frequency requires element spacing of approximately 2.5 mm, presenting significant challenges for signal routing and incorporation of MMICs. By combining (Gallium Nitride) GaN MMIC technology with micro-machined radiators and interconnects and silicon-germanium (SiGe) beamforming MMICs, we are able to meet all the performance and packaging requirements of the linear array feed and enable simultaneous scanning of Ka-band and W-band radars over swath of up to 100 km.

  3. Sounding out erosion on the Mekong river banks: insights from combined terrestrial laser scanning, multibeam echo sounding and acoustic Doppler profiling

    NASA Astrophysics Data System (ADS)

    Best, J.; Hackney, C. R.; Leyland, J.; Darby, S. E.; Parsons, D. R.; Aalto, R. E.; Nicholas, A. P.

    2015-12-01

    Knowledge of bank erosion processes and rates along very large rivers remains incomplete, primarily due to the difficulties of obtaining morphological and flow data close to the bank across various flow stages. Moreover, obtaining such process information through the entire flow and bank depth has also proved challenging. Here, we present data from a series of high spatial resolution topographic (Terrestrial Laser Scanner and Multibeam Echo Sounder) and flow (Acoustic Doppler Current Profiler) surveys undertaken on the Mekong River, Cambodia, which reveal the temporal and spatial evolution of a series of embayments on the outer bank of a large meander. These techniques yield unique data that reveal how the flow field responds to the morphology of the outer bank and subaqueous slump blocks. Specifically, we show that in the early stage of embayment growth, deposited slump blocks induce flow upwelling and bank-directed flow that enhances bank erosion. Our data also suggest that as the initial erosion process continues, a threshold embayment size is reached. Below this threshold, flow separation acts to enhance embayment growth along with the fluid dynamic effects of slump blocks, but above the threshold size, the separation zone in the embayments acts as a protective layer, thus slowing erosion. This field data allows proposition of a new conceptual model of embayment evolution.

  4. Ultrasound Screening for Deep Venous Thrombosis Detection: A Prospective Evaluation of 200 Plastic Surgery Outpatients

    PubMed Central

    2015-01-01

    Background: Our understanding of the pathophysiology of venous thromboembolism is largely based on the experience of orthopedic patients undergoing total joint replacement. Little is known regarding the natural history of venous thromboembolism in plastic surgery outpatients. Today, ultrasound screening, including compression and Doppler color flow imaging, represents the standard for detecting deep venous thromboses. Methods: Ultrasound screening was offered to 200 consecutive plastic surgery outpatients undergoing 205 operations. Patients were scanned before surgery, on the day after surgery, and approximately 1 week after surgery. No patient declined to participate (inclusion rate, 100%). Spontaneous breathing, Avoid gas, Face up, Extremities mobile anesthesia was used, with no chemoprophylaxis. Patient surveys were administered. Results: Six hundred ultrasound screening tests were performed. All scans performed the day after surgery were negative. Only one examination was positive, 8 days after a lipoabdominoplasty. Subsequent scans revealed complete resolution of the thrombosis with anticoagulation. Ninety percent of surveyed patients would choose to have ultrasound screening in the future. Conclusions: The natural history of thromboembolism in plastic surgery outpatients differs from orthopedic patients. The risk of a deep venous thrombosis in a patient treated with Spontaneous breathing, Avoid gas, Face up, Extremities mobile anesthesia is approximately 0.5%. Thromboses are unlikely to develop intraoperatively. In the single affected patient, the thrombosis was located distally, in a location that is less prone to embolism and highly susceptible to anticoagulation. Ultrasound screening is an effective and highly feasible method to identify affected patients for treatment. PMID:25878943

  5. 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.

  6. ANL Doppler flowmeter

    NASA Astrophysics Data System (ADS)

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

    1985-10-01

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

  7. Electromagnetically navigated laparoscopic ultrasound.

    PubMed

    Wilheim, Dirk; Feussner, Hubertus; Schneider, Armin; Harms, Jens

    2003-01-01

    A three-dimensional (3D) representation of laparoscopic ultrasound examinations could be helpful in diagnostic and therapeutic laparoscopy, but has not yet been realised with flexible laparoscopic ultrasound probes. Therefore, an electromagnetic navigation system was integrated into the tip of a conventional laparoscopic ultrasound probe. Navigated 3D laparoscopic ultrasound was compared with the imaging data of 3D navigated transcutaneous ultrasound and 3D computed tomography (CT) scan. The 3D CT scan served as the "gold standard". Clinical applicability in standardized operating room (OR) settings, imaging quality, diagnostic potential, and accuracy in volumetric assessment of various well-defined hepatic lesions were analyzed. Navigated 3D laparoscopic ultrasound facilitates exact definition of tumor location and margins. As compared with the "gold standard" of the 3D CT scans, 3D laparoscopic ultrasound has a tendency to underestimate the volume of the region of interest (ROI) (Delta3.1%). A comparison of 3D laparoscopy and transcutaneous 3D ultrasonography demonstrated clearly that the former is more accurate for volumetric assessment of the ROI and facilitates a more detailed display of the lesions. 3D laparoscopic ultrasound imaging with a navigated probe is technically feasible. The technique facilitates detailed ultrasound evaluation of laparoscopic procedures that involve visual, in-depth, and volumetric perception of complex liver pathologies. Navigated 3D laparoscopic ultrasound may have the potential to promote the practical role of laparoscopic ultrasonography, and become a valuable tool for local ablative therapy. In this article, our clinical experiences with a certified prototype of a 3D laparoscopic ultrasound probe, as well as its in vitro and in vivo evaluation, is reported.

  8. Perineal scanning.

    PubMed

    Jeanty, P; d'Alton, M; Romero, R; Hobbins, J C

    1986-10-01

    Although various techniques have been described to aid in the ultrasound diagnosis of placenta previa and incompetent cervix, these maneuvers depend on the precise identification of the internal cervical os, a feat which is notoriously difficult to accomplish consistently. In an attempt to get a closer view of the cervix we tried another approach. This simple technique of perineal scanning has the potential to help considerably with these problems. PMID:3530265

  9. Doppler effect's contribution to ultrasonic modulation of multiply scattered coherent light: Monte Carlo modeling.

    PubMed

    Elazar, Jovan M; Steshenko, Oleg

    2008-01-15

    Modulation of light by ultrasound in turbid media is investigated by modified public domain software based on the Monte Carlo algorithm. Apart from the recognized modulation mechanisms, originating in scatterers' displacements and refractive index modulation, an additional mechanism, evolving from Doppler shift during photon scattering, is considered. Comparison of the relative contributions from all three mechanisms to light modulation by ultrasound is performed for different medium scattering properties and ultrasound frequencies. Refractive index modulation remains the strongest mechanism for light modulation by ultrasound, but for high ultrasound frequencies and for large scattering coefficients the Doppler effect can become dominant.

  10. Doppler flowmeter

    DOEpatents

    Karplus, H.H.B.; Raptis, A.C.

    1981-11-13

    A Doppler flowmeter impulses an ultrasonic fixed-frequency signal obliquely into a slurry flowing in a pipe and a reflected signal is detected after having been scattered off of the slurry particles, whereby the shift in frequencies between the signals is proportional to the slurry velocity and hence slurry flow rate. This flowmeter filters the Doppler frequency-shift signal, compares the filtered and unfiltered shift signals in a divider to obtain a ratio, and then further compares this ratio against a preset fractional ratio. The flowmeter utilizes a voltage-to-frequency convertor to generate a pulsed signal having a determinable rate of repetition precisely proportional to the divergence of the ratios. The pulsed signal serves as the input control for a frequency-controlled low-pass filter, which provides thereby that the cutoff frequency of the filtered signal is known. The flowmeter provides a feedback control by minimizing the divergence. With the cutoff frequency and preset fractional ratio known, the slurry velocity and hence flow will also be determinable.

  11. Photoacoustic Doppler flowmetry of carbon particles flow using an autocorrelation method

    NASA Astrophysics Data System (ADS)

    Lu, Tao

    2014-11-01

    In order to measure the axial flowing velocity of carbon particle suspension with particle diameter of tens of micrometers, the photoacoustic Doppler (PAD) frequency shift is calculated based on a series of individual A scans using an autocorrelation method. A 532 nm pulsed laser with repetition rate of 20 Hz is used as a pumping source to generate photoacoustic signal. The photoacoustic signals are detected using a focused piezoelectric (PZT) ultrasound transducer with central frequency of 5 MHz. The suspension of carbon particles is driven by a syringe pump. The complex photoacoustic signal is calculated by the Hilbert transformation from time-domain photoacoustic signal, and then it is autocorrelated to calculate the Doppler frequency shift. The photoacoustic Doppler frequency shift is calculated by averaging the autocorrelation results of some individual A scans. The advantage of the autocorrelation method is that the time delay in autocorrelation can be defined by user, and the requirement of high pulse repetition rate is avoided. The feasibility of the proposed autocorrelation method is preliminarily demonstrated by quantifying the motion of a carbon particle suspension with flow velocity from 5 mm/s to 60 mm/s. The experimental results show that there is an approximately linear relation between the autocorrelation result and the setting velocity.

  12. 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.

  13. Cardiological Ultrasound Imaging.

    PubMed

    Thijssen, Johan M; de Korte, Chris L

    2014-01-01

    This review paper is intended for the interested outsider of the field of echocardiography and it presents a short introduction into the numerous ultrasound (US) methods and techniques for anatomical and functional diagnosis of the heart. The basic techniques are generally used for some times already, as there are one dimensional (1D) M(otion) mode, the real time 2D B(rightness) mode technique and the various Doppler measurement techniques and imaging modes. The M-mode technique shows the movements of the tissue in a 1D B-mode display vs. time. The 2D B-mode images are showing the heart contractions and dilations in real time, thus making this technique the basic tool for detecting anatomical disturbances and myocardial (localized) abnormal functioning. Improved image quality is achieved by Second Harmonic Imaging and myocardial perfusion can be quantified using Contrast Agent Imaging. Doppler techniques were introduced in the fifties of last century and used for blood flow velocity measurement. Continuous wave (CW) Doppler has the advantage of allowing measurement of high velocities, as may occur in vascular or valvular stenosis and insufficiency. The exact location of the major Doppler signal received cannot be estimated making this technique ambiguous in some clinical problems. Single gated Pulse Wave (PW) Doppler velocity measurement delivers exact location of the measurement position by using an interactively positioned time (=depth) gate in which the velocity is being measured. The disadvantage of this technique is the relatively low maximum velocity that can be measured. Multigate PW Doppler techniques can be used for the assessment of a velocity profile over the vessel cross section. A more sophisticated use of this technique is the combination with 2D B-mode imaging in the color Doppler mode, called "color flow mapping", in which the multigate Doppler signal is color coded and shown in 2D format overlayed in the conventional 2D B mode image. In the past

  14. Reconstructing two-dimensional acoustic object fields by use of digital phase conjugation of scanning laser vibrometry recordings.

    PubMed

    Zipser, Lothar; Franke, Heinz; Olsson, Erik; Molin, Nils-Erik; Sjödahl, Mikael

    2003-10-10

    A scanning laser Doppler vibrometer is used to record two-dimensional ultrasound fields in air. The laser light of the vibrometer traverses the sound field to and from a rigid reflector and determines the velocity field, a quantity proportional to the sound pressure rate, in each scanned point relative to the sound source. The object sound is the scattered field from objects outside the recording area. Digital reconstruction by use of phase conjugation (time reversal) of the object sound field is then performed, and the original object field intensity and phase is reconstructed.

  15. Photoacoustic Doppler flowmetry of carbon particles flow using an autocorrelation method

    NASA Astrophysics Data System (ADS)

    Lu, Tao

    2014-09-01

    In order to measure the axial flowing velocity of a suspension carbon particles of tens of micometer-scale, the photoacoustic doppler frequency shift was calculated from a series of individual A scans using a autocorrelation method. A 532nm pulsed laser with the repetition rate of 20Hz was used as a pumping source to generate photoacoustic signal. The photoacoustic signals were detected using a focused PZT ultrasound transducer with central frequency of 5MHz. The suspension of carbon particles was driven by a syringe pump. Firstly, the complex photoacoustic signal was calculated by the Hilbert transformation from time-domain photoacoustic signal. The complex photoacoustic signal was then autocorrelated to calculate doppler frequency shift. The flow velocity was calculated by averaging the autocorrelation results of individual A scans. In comparison , the previously reported data processing methods using cross-correlation method in time domain or frequency domain require high sequential scanning rate or high laser repetition rate up to several kHz to avoid aliasing or uncorrelation between sequential waveform pairs. But it is difficult to get several kHz repetition rate for a single pulsed laser and the correlation between waveform pairs of sequential A scans were also limited by the laser repetition rate. To solve the problem, we used the autocorrelation method of individual A scans to calculated Doppler frequency shift. The time delay can be user defined to avoid aliasing. The feasibility of the proposed autocorrelation method was preliminarily demonstrated by quantifying the motion of a carbon particles suspension flow from 5 to 60 mm/s. The experimental results showed that the autocorrelation result approximately agreed with the setting velocity linearly.

  16. Acoustic output measured by thermal and mechanical indices during fetal echocardiography at the time of the first trimester scan.

    PubMed

    Nemescu, Dragos; Berescu, Anca

    2015-01-01

    We measured acoustic output, expressed as the thermal index (TI) and mechanical index (MI), during fetal echocardiography at the time of the first trimester scan. TI and MI were retrieved from the saved displays during gray-mode, high-definition color flow Doppler and pulsed-wave Doppler (tricuspid flow) ultrasound examinations of the fetal heart and from the ductus venosus assessment. A total of 399 fetal cardiac examinations were evaluated. There was a significant increase in TI values from B-mode studies (0.07 ± 0.04 [mean ± SD]) to color flow mapping (0.2 ± 0.0) and pulsed-wave Doppler studies (0.36 ± 0.05). The TI from ductus venosus assessment (0.1 ± 0.01) was significantly lower than those from Doppler examinations of the heart. MI values from B-mode scans (0.65 ± 0.12) and color flow mapping (0.71 ± 0.11) were comparable, although different, and both values were higher than those from pulsed-wave Doppler tricuspid evaluation (0.39 ± 0.03). There were no differences in MI values from power Doppler assessment between the tricuspid flow and ductus venosus. Safety indices were remarkably stable and were largely constant, especially for color Doppler (TI), tricuspid flow (MI) and ductus venosus assessment (TI, MI). We acquired satisfactory Doppler images and/or signals at acoustic levels that were lower than the actual recommendations and never reached a TI of 0.5.

  17. Airborne cw Doppler lidar (ADOLAR)

    NASA Astrophysics Data System (ADS)

    Rahm, Stefan; Werner, Christian; Nagel, E.; Herrmann, H.; Klier, M.; Knott, H. P.; Haering, R.; Wildgruber, J.

    1994-12-01

    During the last 10 years the DLR container LDA (Laser Doppler Anemometer) was used for many wind related measurements in the atmospheric boundary layer. The experience out of this were used to construct an airborne Doppler lidar ADOLAR. Based on the available Doppler lidars it is now proposed to perform a campaign to demonstrate the concept of the spaceborne sensor ALADIN, and to answer some questions concerning the signal quality from clouds, water and land. For the continuous wave CO2 laser, the energy is focused by the telescope into the region of investigation. Some of the radiation is back scattered by small aerosol particles drifting with the wind speed through the sensing volume. The back scattered radiation is collected by the telescope and detected by coherent technique. With the laser Doppler method one gets the radial wind component. To determine the magnitude and direction of the horizontal wind, some form of scanning in azimuth and elevation is required. To keep the airborne system compact, the transceiver optics is directly coupled to a wedge scanner which provides the conical scan with the axis in Nadir direction from the aircraft. The system ADOLAR was tested in 1994. Results of the flight over the lake Ammersee are presented and are compared with the data of the inertial reference system of the aircraft.

  18. Intravascular ultrasound

    MedlinePlus

    IVUS; Ultrasound - coronary artery; Endovascular ultrasound; Intravascular echocardiography ... A tiny ultrasound wand is attached to the top of a thin tube. This tube is called a catheter. The catheter ...

  19. Duplex ultrasound

    MedlinePlus

    Vascular ultrasound; Peripheral vascular ultrasound ... Deane CR, Goss DE. Peripheral arteries and veins. In: Allan PL, Baxter GM, Weston MJ, eds. Allan & Baxter: Clinical Ultrasound . 3rd ed. Philadelphia, PA: Elsevier ...

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

    NASA Astrophysics Data System (ADS)

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

    2010-02-01

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

  1. 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.

  2. An introduction and guide to effective Doppler assessment.

    PubMed

    Benbow, Maureen

    2014-12-01

    Accurate and timely diagnosis of leg ulceration is an essential factor in making evidence-based, effective decisions regarding patient management with the aim of swift wound healing and/or referral to the appropriate specialty. Nurses are professionally responsible for ensuring that patients receive the appropriate assessment and evidence-based management. This article examines the most up-to-date guidance on Doppler ultrasound as a key element of this assessment. Approaches to assessment will be explored, with emphasis on the need to include a Doppler ultrasound as one key element of a larger, holistic assessment. An introduction to the ankle-brachial pressure index (ABPI) will be given, followed by a step-by-step guide to standard procedures for carrying out a full Doppler ultrasound. Alternative options for measuring ABPI are also provided. PMID:25478852

  3. Doppler micro sense and avoid radar

    NASA Astrophysics Data System (ADS)

    Gorwara, Ashok; Molchanov, Pavlo; Asmolova, Olga

    2015-10-01

    There is a need for small Sense and Avoid (SAA) systems for small and micro Unmanned Aerial Systems (UAS) to avoid collisions with obstacles and other aircraft. The proposed SAA systems will give drones the ability to "see" close up and give them the agility to maneuver through tight areas. Doppler radar is proposed for use in this sense and avoid system because in contrast to optical or infrared (IR) systems Doppler can work in more harsh conditions such as at dusk, and in rain and snow. And in contrast to ultrasound based systems, Doppler can better sense small sized obstacles such as wires and it can provide a sensing range from a few inches to several miles. An SAA systems comprised of Doppler radar modules and an array of directional antennas that are distributed around the perimeter of the drone can cover the entire sky. These modules are designed so that they can provide the direction to the obstacle and simultaneously generate an alarm signal if the obstacle enters within the SAA system's adjustable "Protection Border". The alarm signal alerts the drone's autopilot to automatically initiate an avoidance maneuver. A series of Doppler radar modules with different ranges, angles of view and transmitting power have been designed for drones of different sizes and applications. The proposed Doppler radar micro SAA system has simple circuitry, works from a 5 volt source and has low power consumption. It is light weight, inexpensive and it can be used for a variety of small unmanned aircraft.

  4. Analysis of Doppler lidar data

    NASA Technical Reports Server (NTRS)

    Rothermel, J.

    1985-01-01

    Dual Doppler lidar analyses of data taken by pulsed lidars demonstrated feasibility of deriving wind fields from coordinated lidar scans. Limited case histories of thunderstorm outflows were obtained. Co-located comparison between Marshall Space Flight Center lidar and NCAR 5.5 cm radar demonstrated desirability of lidar in cases of marginal radar reflectivity in clear air and low-elevation scans. Analysis continued on backscattered intensity and velocity measurements made from April 1983 to February 1984. A slant path method was used to calculate vertical profiles of volumetric backscatter and adsorption in the lower troposphere. High-quality VAD scans were identified as candidates for investigating feasibility of calculating horizontal motion fields using single Doppler lidar. Activities during FY-85 also included participation in Fall 1984 airborne Doppler lidar flight experiments. Preliminary data review was begun using McIdas system. Analysis of backscatter and absorpiton profiles continues. Focus is on understanding spatial and temporal variations, as well as frequency distribution, of backscatter at several tropospheric levels. Results from this study provide input to evaluation of clean/dirty airmass hypothesis of aerosol distribution. Assistance is being given to preparation of a comprehensive, global backscatter measurement plan. Analysis of data from Fall 1984 flight experiments is just beginning. Work has begun on preprocessing data to minimize errors due to electro-optic modulator malfunction during flights.

  5. 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

  6. Lung ultrasound in the critically ill.

    PubMed

    Lichtenstein, Daniel A

    2014-01-01

    ), 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

  7. [Comprehensive ultrasound diagnosis of orbital tumors and preudotumors].

    PubMed

    Aznabaev, M T; Gabdrakhmanova, A F; Gaĭsina, G F

    2006-01-01

    A comprehensive ultrasound examination was made in 37 patients with orbital tumors and pseudotumors. The basic differential diagnostic sonographic and Doppler signs were defined in capillary hemangioma, vasculitis at the stage of infiltration and malignancies of the orbit.

  8. Color Doppler Imaging of Cardiac Catheters Using Vibrating Motors

    PubMed Central

    Reddy, Kalyan E.; Light, Edward D.; Rivera, Danny J.; Kisslo, Joseph A.; Smith, Stephen W.

    2010-01-01

    We attached a miniature motor rotating at 11,000 rpm onto the proximal end of cardiac electrophysiological (EP) catheters in order to produce vibrations at the tip which were then visualized by color Doppler on ultrasound scanners. We imaged the catheter tip within a vascular graft submerged in a water tank using the Volumetrics Medical Imaging 3D scanner, the Siemens Sonoline Antares 2D scanner, and the Philips ie33 3D ultrasound scanner with TEE probe. The vibrating catheter tip was visualized in each case though results varied with the color Doppler properties of the individual scanner. PMID:19514134

  9. 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)

  10. 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.

  11. Controlled Study of Traditional Ultrasound and Ultrasound Elastography on the Diagnosis of Breast Masses.

    PubMed

    Li, Qin; Wang, Ling; Wu, Haojie; Wei, Xiangkun; Duan, Yajie; Xu, Lingyao; Yang, Zheng; Liu, Liu

    2015-12-01

    This study aims to explore the application values of traditional ultrasound (contrast ultrasound [CUS]) and ultrasound elastography (UE) (including gray-scale ultrasound, color Doppler flow imaging, spectral Doppler ultrasound) in the diagnosis of breast masses. Postoperative histopathological diagnosis was used as the gold standard. One hundred seventy benign and malignant breast lesions from our hospital were retrospectively analyzed. The sensitivity, specificity, and diagnostic accuracy differences of breast malignancy diagnosed by UE and CUS were compared. The sensitivity, specificity, and diagnostic accuracy rates of breast malignancy diagnosed by UE were 98.7%, 90.2%, and 97.7%, whereas that by CUS were 93.6%, 76.1%, and 78.9%, respectively. The specificity and diagnosis rate of UE in the differential diagnosis of malignant breast lesions are superior to those of CUS and have an important clinical value.

  12. 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

  13. 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.

  14. Ultrasound and the IRB

    ERIC Educational Resources Information Center

    Epstein, Melissa A.

    2005-01-01

    The purpose of this paper is to assist researchers in writing their research protocols and subject consent forms so that both the Institutional Review Board (IRB) and subjects are assured of the minimal risk associated with diagnostic B-scan ultrasound as it is used in speech research. There have been numerous epidemiological studies on fetal…

  15. DOPPLER WEATHER SYSTEM

    2002-08-05

    The SRS Doppler Weather System consists of a Doppler Server, A Master Server (also known as the Weather Server), several Doppler Slave Servers, and client-side software program called the Doppler Radar Client. This system is used to display near rel-time images taken from the SRS Weather Center's Doppler Radar computer. The Doppler Server is software that resides on the SRS Doppler Computer. It gathers raw data, 24-bit color weather images via screen scraping ever fivemore » minutes as requested by the Master Server. The Doppler Server then reduces the 24-bit color images to 8-bit color using a fixed color table for analysis and compression. This preserves the fidelity of the image color and arranges the colors in specific order for display. At the time of color reduction, the white color used for the city names on the background images are remapped to a different index (color) of white that the white on the weather scale. The Weather Server places a time stamp on the image, then compresses the image and passes it to all Doppler Slave servers. Each of the Doppler Slave servers mainitain a circular buffer of the eight most current images representing the last 40 minutes of weather data. As a new image is added, the oldest drops off. The Doppler Radar Client is an optional install program for any site-wide workstation. When a Client session is started, the Client requests Doppler Slave server assignment from the Master Server. Upon its initial request to the Slave Server, the Client obtains all eight current images and maintains its own circular buffer, updating its images every five minutes as the Doppler Slave is updated. Three background reference images are stored as part of the Client. The Client brings up the appropriate background image, decompresses the doppler data, and displays the doppler data on the background image.« less

  16. DOPPLER WEATHER SYSTEM

    SciTech Connect

    Berlin, Gary J.

    2002-08-05

    The SRS Doppler Weather System consists of a Doppler Server, A Master Server (also known as the Weather Server), several Doppler Slave Servers, and client-side software program called the Doppler Radar Client. This system is used to display near rel-time images taken from the SRS Weather Center's Doppler Radar computer. The Doppler Server is software that resides on the SRS Doppler Computer. It gathers raw data, 24-bit color weather images via screen scraping ever five minutes as requested by the Master Server. The Doppler Server then reduces the 24-bit color images to 8-bit color using a fixed color table for analysis and compression. This preserves the fidelity of the image color and arranges the colors in specific order for display. At the time of color reduction, the white color used for the city names on the background images are remapped to a different index (color) of white that the white on the weather scale. The Weather Server places a time stamp on the image, then compresses the image and passes it to all Doppler Slave servers. Each of the Doppler Slave servers mainitain a circular buffer of the eight most current images representing the last 40 minutes of weather data. As a new image is added, the oldest drops off. The Doppler Radar Client is an optional install program for any site-wide workstation. When a Client session is started, the Client requests Doppler Slave server assignment from the Master Server. Upon its initial request to the Slave Server, the Client obtains all eight current images and maintains its own circular buffer, updating its images every five minutes as the Doppler Slave is updated. Three background reference images are stored as part of the Client. The Client brings up the appropriate background image, decompresses the doppler data, and displays the doppler data on the background image.

  17. Role of ultrasound in posteromedial tarsal tunnel syndrome: 81 cases.

    PubMed

    Fantino, Olivier

    2014-06-01

    Posteromedial tarsal tunnel syndrome is a disorder affecting the tibial nerve or its branches. Diagnosis is established on the basis of physical examination and can be confirmed by electrophysiological evidence. However, diagnostic imaging is always required to identify the possible site of compression. High-resolution ultrasound (US) is playing an increasingly important role in the study of the nerves thanks to a series of advantages over magnetic resonance imaging, such as lower costs and widespread availability, high spatial resolution, fast examination using axial scans, dynamic and comparative studies, possibility of carrying out a study with the patient in the standing position, US Tinel sign finding, and the contribution of color/power Doppler US. We present the results obtained in a series of 81 patients who underwent US imaging between 2008 and 2013 due to posteromedial tarsal tunnel syndrome.

  18. 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

  19. A genomewide association mapping study using ultrasound-scanned information identifies potential genomic regions and candidate genes affecting carcass traits in Nellore cattle.

    PubMed

    Santana, M H A; Ventura, R V; Utsunomiya, Y T; Neves, H H R; Alexandre, P A; Oliveira Junior, G A; Gomes, R C; Bonin, M N; Coutinho, L L; Garcia, J F; Silva, S L; Fukumasu, H; Leme, P R; Ferraz, J B S

    2015-12-01

    The aim of this study was to identify candidate genes and genomic regions associated with ultrasound-derived measurements of the rib-eye area (REA), backfat thickness (BFT) and rumpfat thickness (RFT) in Nellore cattle. Data from 640 Nellore steers and young bulls with genotypes for 290 863 single nucleotide polymorphisms (SNPs) were used for genomewide association mapping. Significant SNP associations were explored to find possible candidate genes related to physiological processes. Several of the significant markers detected were mapped onto functional candidate genes including ARFGAP3, CLSTN2 and DPYD for REA; OSBPL3 and SUDS3 for BFT; and RARRES1 and VEPH1 for RFT. The physiological pathway related to lipid metabolism (CLSTN2, OSBPL3, RARRES1 and VEPH1) was identified. The significant markers within previously reported QTLs reinforce the importance of the genomic regions, and the other loci offer candidate genes that have not been related to carcass traits in previous investigations.

  20. Infrared thermography and ultrasound C-scan for non-destructive evaluation of 3D carbon fiber materials: a comparative study

    NASA Astrophysics Data System (ADS)

    Zhang, Hai; Genest, Marc; Robitaille, Francois; Maldague, Xavier; West, Lucas; Joncas, Simon; Leduc, Catherine

    2015-05-01

    3D Carbon fiber polymer matrix composites (3D CF PMCs) are increasingly used for aircraft construction due to their exceptional stiffness and strength-to-mass ratios. However, defects are common in the 3D combining areas and are challenging to inspect. In this paper, Stitching is used to decrease these defects, but causes some new types of defects. Infrared NDT (non-destructive testing) and ultrasound NDT are used. In particular, a micro-laser line thermography technique (micro-LLT) and a micro-laser spot thermography (micro-LST) with locked-in technique are used to detect the micro-defects. In addition, a comparative study is conducted by using pulsed thermography (PT), vibrothermography (VT). In order to confirm the types of the defects, microscopic inspection is carried out before NDT work, after sectioning and polishing a small part of the sample..

  1. Thyroid ultrasound

    PubMed Central

    Chaudhary, Vikas; Bano, Shahina

    2013-01-01

    Thyroid ultrasonography has established itself as a popular and useful tool in the evaluation and management of thyroid disorders. Advanced ultrasound techniques in thyroid imaging have not only fascinated the radiologists but also attracted the surgeons and endocrinologists who are using these techniques in their daily clinical and operative practice. This review provides an overview of indications for ultrasound in various thyroid diseases, describes characteristic ultrasound findings in these diseases, and illustrates major diagnostic pitfalls of thyroid ultrasound. PMID:23776892

  2. 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

    2014-10-01

    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.

  3. 3D ultrafast ultrasound imaging in vivo

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    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.

  4. 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

    2014-10-01

    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. PMID:25207828

  5. 3D Ultrafast Ultrasound Imaging In Vivo

    PubMed Central

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

    2014-01-01

    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 real-time 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 three dimensions 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 capability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3-D Shear-Wave Imaging, 3-D Ultrafast Doppler Imaging and finally 3D Ultrafast combined Tissue and Flow Doppler. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3-D Ultrafast Doppler was used to obtain 3-D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, for the first time, the complex 3-D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, and the 3-D 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 3-D Ultrafast Ultrasound Imaging for the 3-D real-time 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. PMID:25207828

  6. Christian Doppler and the Doppler effect

    NASA Astrophysics Data System (ADS)

    Toman, Kurt

    1984-04-01

    A summary is given of Doppler's life and career. He was born 180 years ago on November 29, 1803, in Salzburg, Austria. He died on March 17, 1853 in Venice. The effect bearing his name was first announced in a presentation before the Royal Bohemian Society of the Sciences in Prague on May 25, 1842. Doppler considered his work a generalization of the aberration theorem as discovered by Bradley. With it came the inference that the perception of physical phenomena can change with the state of motion of the observer. Acceptance of the principle was not without controversy. In 1852, the mathematician Petzval claimed that no useful scientific deductions can be made from Doppler's elementary equations. In 1860, Ernst Mach resolved the misunderstanding that clouded this controversy. The Doppler effect is alive and well. Its role in radio science and related disciplines is enumerated.

  7. Focused ultrasound in ophthalmology

    PubMed Central

    Silverman, Ronald H

    2016-01-01

    The use of focused ultrasound to obtain diagnostically significant information about the eye goes back to the 1950s. This review describes the historical and technological development of ophthalmic ultrasound and its clinical application and impact. Ultrasound, like light, can be focused, which is crucial for formation of high-resolution, diagnostically useful images. Focused, single-element, mechanically scanned transducers are most common in ophthalmology. Specially designed transducers have been used to generate focused, high-intensity ultrasound that through thermal effects has been used to treat glaucoma (via ciliodestruction), tumors, and other pathologies. Linear and annular transducer arrays offer synthetic focusing in which precise timing of the excitation of independently addressable array elements allows formation of a converging wavefront to create a focus at one or more programmable depths. Most recently, linear array-based plane-wave ultrasound, in which the array emits an unfocused wavefront and focusing is performed solely on received data, has been demonstrated for imaging ocular anatomy and blood flow. While the history of ophthalmic ultrasound extends back over half-a-century, new and powerful technologic advances continue to be made, offering the prospect of novel diagnostic capabilities. PMID:27757007

  8. Ultrasound for neuraxial blockade.

    PubMed

    Srinivasan, Karthikeyan Kallidaikurichi; Lee, Peter John; Iohom, Gabriella

    2014-12-01

    Neuraxial blockade is still largely performed as a blind procedure. Despite of developments in the type of needles used and drugs administered, the process of locating the epidural or intra-thecal space is still limited to identification of landmarks by palpation and reliance on tactile feedback of the operator. Ultrasound has provided the long needed "eye" to the procedure and has already shown promise of improving the safety and efficacy or neuraxial blocks. This review focuses on understanding the sonoanatomy of the neuraxial space, performing a systematic pre-procedural ultrasound scan, and reviewing the available evidence. PMID:25463890

  9. 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.

  10. 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. PMID:26276956

  11. [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.

  12. Transverse flowmetry of carbon particles based on photoacoustic Doppler standard deviation using an auto-correlation method

    NASA Astrophysics Data System (ADS)

    Lu, Tao; Sun, Li-jun

    2015-05-01

    In order to measure the flow velocity of carbon particle suspension perpendicular to the receiving axis of ultrasound transducer, the standard deviation of photoacoustic Doppler frequency spectrum is used to estimate the bandwidth broadening, and the spectrum standard deviation is calculated by an auto-correlation method. A 532 nm pulsed laser with the repetition rate of 20 Hz is used as a pumping source to generate photoacoustic signal. The photoacoustic signals are detected using a focused PZT ultrasound transducer with the central frequency of 10 MHz. The suspension of carbon particles is driven by a syringe pump. The complex photoacoustic signal is calculated by Hilbert transformation from time domain signal before auto-correlation. The standard deviation of the Doppler bandwidth broadening is calculated by averaging the auto-correlation results of several individual A scans. The feasibility of the proposed method is demonstrated by measuring the spectrum standard deviation of the transversal carbon particle flow from 5.0 mm/s to 8.4 mm/s. The experimental results show that the auto-correlation result is approximately linearly distributed within the measuring range.

  13. The Role of the Carotid Doppler Examination in the Evaluation of Atherosclerotic Changes in β-Thalassemia Patients

    PubMed Central

    Abdelsamei, Hoda A.; El-Sherif, Ashraf M.; Ismail, Ahlam M.; Abdel Hakeem, Gehan L.

    2015-01-01

    Background Iron overload in patients with beta-thalassemia major (BTM) lead to alterations in the arterial structures and the thickness of the carotid arteries. Doppler ultrasound scanning of extra-cranial internal carotid arteries is non-invasive and relatively quick to perform and may identify children at increased risk of stroke that would otherwise be missed. Increased carotid artery intima media thickness (CIMT) is a structural marker for early atherosclerosis and correlates with the vascular risk factors and to the severity and extent of coronary artery disease. Objective To evaluate the role of carotid Doppler examination and CIMT measurement as a predictor of atherosclerotic changes in BTM children with iron overload. Patients and Methods Sixty two children with BTM and, thirty age and sex matched normal controls were included. Complete blood count, ferritin, serum cholesterol were done, as well as carotid Doppler ultrasonography to measure the CIMT in both patients and controls. Results CIMT of thalassemic patients was significantly increased compared to controls (p=0.001). There was a significant positive correlation between CIMT and patient’s age, the duration from first blood transfusion, serum cholesterol and, iron overload parameters as serum ferritin, frequency of blood transfusion, iron chelation. The length of the transfusion period was the highest risk factor, and an inadequate iron chelation was a further risk factor. Significant negative correlation was found between CIMT and hematocrit value while no significant correlation was found between CIMT and weight, height, BMI centiles and Hb level. Conclusion Carotid Doppler is very useful in measurement of CIMT that increased in thalassemic patients that shows a strong relationship with features of iron overload. Routine Doppler measurement of CIMT in these patients is recommended to predict early atherosclerotic changes as well as in follow-up. PMID:25745550

  14. Advanced Doppler tracking experiments

    NASA Technical Reports Server (NTRS)

    Armstrong, J. W.

    1989-01-01

    The Doppler tracking method is currently the only technique available for broadband gravitational wave searches in the approx. 10(exp -4) to 10(exp -1) Hz low frequency band. A brief review is given of the Doppler method, a discussion of the main noise sources, and a review of experience with current spacecraft and the prospects for sensitivity improvements in an advanced Doppler tracking experiment.

  15. Advances in Doppler OCT

    PubMed Central

    Liu, Gangjun; Chen, Zhongping

    2014-01-01

    We review the principle and some recent applications of Doppler optical coherence tomography (OCT). The advances of the phase-resolved Doppler OCT method are described. Functional OCT algorithms which are based on an extension of the phase-resolved scheme are also introduced. Recent applications of Doppler OCT for quantification of flow, imaging of microvasculature and vocal fold vibration, and optical coherence elastography are briefly discussed. PMID:24443649

  16. Office-based ultrasound for the urologist.

    PubMed

    Terris, Martha K; Klaassen, Zachary

    2013-11-01

    This article presents an overview of the techniques and indications for office-based ultrasound for the clinical urologist. Discussion includes renal, bladder, scrotal, penile Doppler, and prostate ultrasonography and a review of the pertinent literature and images for each anatomic location.

  17. Clinical Applications of Doppler OCT and OCT Angiography

    NASA Astrophysics Data System (ADS)

    Tan, Ou; Jia, Yali; Wei, Eric; Huang, David

    Doppler optical coherence tomography (OCT) is a functional extension of OCT that allows for the visualization and measurement of blood flow [1, 2]. Phase-resolved Doppler OCT has become a standard algorithm for measuring Doppler shift with Fourier-domain (FD)-OCT because of its high velocity sensitivity [3]. In ophthalmology, several methods have been developed to measure in vivo retinal blood flow using this algorithm. Since Doppler OCT measures only the velocity component parallel to the OCT probe beam, additional information is needed to calculate absolute velocity and volumetric flow rate. One method is to employ two OCT beams with a fixed offset in incidence angles [4, 5]. However, this approach requires special hardware and is not compatible with commercial single-beam OCT systems. Another approach is to use special scan patterns to measure the Doppler angle (angle between the OCT beam and the blood vessel). Some groups used concentric scan patterns [6, 7], while other groups used raster scan patterns [8, 9]. Finally, Srinivasan et al. developed en face Doppler OCT for cerebral blood flow calculation, which obviated the need for Doppler angle estimation [10]. Bauman et al. adapted the method for total retinal blood flow (TRBF) calculation with ultrafast swept-source OCT [11]. In this chapter, we focus our attention on the double-circular scan pattern developed in our research group, which has been used in a number of clinical studies for preliminary demonstration of utility.

  18. Repeat scanning technology for laser ultrasonic propagation imaging

    NASA Astrophysics Data System (ADS)

    Lee, Jung-Ryul; Yenn Chong, See; Sunuwar, Nitam; Park, Chan Yik

    2013-08-01

    Laser ultrasonic scanning in combination with contact or non-contact sensors provides new paradigms in structural health management (SHM) and non-destructive in-process quality control (IPQC) for large composite structures. Wave propagation imaging technology based on laser ultrasonic scanning and fixed-point sensing shows remarkable advantages, such as minimal need for embedded sensors in SHM, minimum invasive defect visualization in IPQC and general capabilities of curved and complex target inspection, and temporal reference-free inspection. However, as with other SHM methods and non-destructive evaluation based on ultrasound, the signal-to-noise ratio (SNR) is a prevalent issue in real structural applications, especially with non-contact thin-composite sensing or with thick and heterogeneous composites. This study proposes a high-speed repeat scanning technique for laser ultrasonic propagation imaging (UPI) technology, which is realized with the scanning speed of 1 kHz of a Q-switched continuous wave laser, and precise control of the laser beam pulses for identical point scanning. As a result, the technique enables the achievement of significant improvement in the SNR to inspect real-world composite structures. The proposed technique provides enhanced results for impact damage detection in a 2 mm thick wing box made of carbon-fiber-reinforced plastic, despite the low sensitivity of non-contact laser ultrasonic sensing. A field-applicable pure laser UPI system has been developed using a laser Doppler vibrometer as the non-contact ultrasonic sensor. The proposed technique enables the visualization of the disbond defect in a 15 mm thick wind blade specimen made of glass-fiber-reinforced plastic, despite the high dissipation of ultrasound in the thick composite.

  19. 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".

  20. Maternal ophthalmic artery Doppler velocimetry in pre-eclampsia in Southwestern Nigeria

    PubMed Central

    Olatunji, Richard Busayo; Adekanmi, Ademola Joseph; Obajimi, Millicent Olubunmi; Roberts, Olumuyiwa Adebola; Ojo, Temitope Olumuyiwa

    2015-01-01

    Background Pre-eclampsia (PE) poses a serious challenge to maternal and fetal health in Africa. It is associated with hemodynamic changes that may affect the internal carotid/ophthalmic artery circulation with consequent neuro-ophthalmic manifestations. Ophthalmic artery Doppler (OAD) ultrasound is an important tool that can be used to detect hemodynamic changes in PE and monitor its severity. In this study, we evaluated hemodynamic changes on OAD ultrasound in the ophthalmic arteries of pre-eclamptic women and compared these with values in healthy pregnant women. Methods OAD parameters, such as, peak systolic velocity, peak diastolic velocity, end diastolic velocity, pulsatility index, and peak ratio, were measured on transorbital triplex ultrasound scan with a 7–10 MHz multifrequency linear transducer in 42 consenting pre-eclamptic patients and 41 pregnant controls matched for maternal age, gestational age, and parity at the Department of Radiology, University College Hospital, Ibadan. Univariate, bivariate, and receiver operating characteristic curve data analyses were performed. P<0.05 was considered to be statistically significant. Results Mean resistivity index, pulsatility index, and peak systolic velocity were significantly lower in pre-eclamptic patients than in the controls. Mean peak diastolic velocity, end diastolic velocity, and peak ratio were significantly higher in the pre-eclamptic group. The receiver operating characteristic curve showed that the resistivity index (sensitivity 75%, specificity 77.8%) could distinguish mild from severe PE while the peak ratio (sensitivity 90.5%, specificity 81.3%) could accurately detect PE. Conclusion OAD ultrasound can be used to monitor patients with PE for early detection of progression to severe forms before cerebral complications develop. OAD screening of patients at high risk for PE can also detect early changes of hemodynamic derangement. PMID:26229508

  1. Doppler and Zeeman Doppler Imaging of Stars

    NASA Astrophysics Data System (ADS)

    Kochukhov, Oleg

    In this chapter we discuss the problem of reconstructing two-dimensional stellar surface maps from the variability of intensity and/or polarisation profiles of spectral lines. We start by outlining the main principles of the scalar Doppler imaging problem concerned with recovering maps of chemical spots, temperature or brightness from the intensity spectra. After presenting the physical and mathematical foundations of this remote sensing method, we review its applications to mapping different types of spots in early-type chemically peculiar and late-type active stars, and non-radial pulsations in early-type stars. We also discuss an extension of Doppler imaging to the problem of recovering vector distributions of stellar magnetic fields from spectropolarimetric observations and review applications of this Zeeman Doppler imaging technique in the context of stellar magnetism studies.

  2. The Cognitive Doppler.

    ERIC Educational Resources Information Center

    Kozoil, Micah E.

    1989-01-01

    Discusses the learning needs of students in the concrete operational stage in mathematics. Identifies the phenomenon of reduced cognitive performance in an out-of-class environment as the "Cognitive Doppler." Suggests methods of reducing the pronounced effects of the Cognitive Doppler by capitalizing on the students' ability to memorize effective…

  3. Ultrasound screening for fetal abnormalities.

    PubMed

    Chitty, L S

    1995-12-01

    Ultrasound screening for fetal abnormalities is increasingly becoming part of routine antenatal care in Europe and the UK. However, there has been very little formal evaluation of this practice. In this article reports of routine ultrasound screening are reviewed and the advantages and disadvantages discussed. The majority of routine anomaly scanning is done in the second trimester but there may be a case for screening at other times in pregnancy and alternative anomaly screening policies are discussed. PMID:8710765

  4. Ultrasound physics.

    PubMed

    Shriki, Jesse

    2014-01-01

    Bedside ultrasound has become an important modality for obtaining critical information in the acute care of patients. It is important to understand the physics of ultrasound in order to perform and interpret images at the bedside. The physics of both continuous wave and pulsed wave sound underlies diagnostic ultrasound. The instrumentation, including transducers and image processing, is important in the acquisition of appropriate sonographic images. Understanding how these concepts interplay with each other enables practitioners to obtain the best possible images.

  5. 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

  6. Accuracy of heart strain rate calculation derived from Doppler tissue velocity data

    NASA Astrophysics Data System (ADS)

    Santos, Andres; Ledesma-Carbayo, Maria J.; Malpica, Norberto; Desco, Manuel; Antoranz, Jose C.; Marcos-Alberca, Pedro; Garcia-Fernandez, Miguel A.

    2001-05-01

    Strain Rate (SR) Imaging is a recent imaging technique that provides information about regional myocardial deformation by measuring local compression and expansion rates. SR can be obtained by calculating the local in-plane velocity gradients along the ultrasound beam from Doppler Tissue velocity data. However, SR calculations are very dependent on the image noise and artifacts, and different calculation algorithms may provide inconsistent results. This paper compares techniques to calculate SR. 2D Doppler Tissue Images (DTI) are acquired with an Acuson Sequoia scanner. Noise was measured with the aid of a rotating phantom. Processing is performed on polar coordinates. For each image, after removal of black spot artifacts by a selective median filter, two different SR calculation methods have been implemented. In the first one, SR is computed as the discrete velocity derivative, and noise is reduced with a variable-width gaussian filter. In the second method a smoothing cubic spine is calculated for every scan line according to the noise level and the derivative is obtained from an analytical expression. Both methods have been tested with DTI data from synthetic phantoms and normal volunteers. Results show that noise characteristics, border effects and the adequate scale are critical to obtain meaningful results.

  7. Prevalence of defined ultrasound findings of unknown significance at the second trimester fetal anomaly scan and their association with adverse pregnancy outcomes: the Welsh study of mothers and babies population‐based cohort

    PubMed Central

    Hurt, Lisa; Wright, Melissa; Dunstan, Frank; Thomas, Susan; Brook, Fiona; Morris, Susan; Tucker, David; Wills, Marilyn Ann; Davies, Colin; John, Gareth; Fone, David

    2015-01-01

    Abstract Objective The aim of this article was to estimate the population prevalence of seven defined ultrasound findings of uncertain significance (‘markers’) in the second trimester and the associated risk of adverse pregnancy outcomes. Method A prospective record‐linked cohort study of 30 078 pregnant women who had second trimester anomaly scans between July 2008 and March 2011 in Wales was conducted. Results The prevalence of markers ranged from 43.7 per 1000 singleton pregnancies for cardiac echogenic foci [95% confidence interval (CI): 38.8, 51.1] to 0.6 for mild‐to‐moderate ventriculomegaly (95% CI: 0.3, 1.0). Isolated echogenic bowel was associated with an increased risk of congenital anomalies [risk ratio (RR) 4.54, 95% CI: 2.12, 9.73] and preterm birth (RR 2.30, 95% CI: 1.08, 4.90). Isolated pelvicalyceal dilatation was associated with an increased risk of congenital anomalies (RR 3.82, 95% CI: 2.16, 6.77). Multiple markers were associated with an increased risk of congenital anomalies (RR 5.00, 95% CI: 1.35, 18.40) and preterm birth (RR 3.38, 95% CI 1.20, 9.53). Conclusions These data are useful for counselling families and developing clinical guidance and care pathways following the detection of markers in clinical practice, particularly the need for follow‐up scans to monitor placental function and growth in pregnancies with isolated echogenic bowel, and further investigation for multiple markers. © 2015 The Authors. Prenatal Diagnosis published by John Wiley & Sons Ltd. PMID:26475362

  8. 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

  9. Doppler radar flowmeter

    DOEpatents

    Petlevich, Walter J.; Sverdrup, Edward F.

    1978-01-01

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

  10. Use of Sonicated Albumin (Infoson) to Enhance Arterial Spectral and Color Doppler Imaging

    SciTech Connect

    Abildgaard, Andreas; Egge, Tor S.; Klow, Nils-Einar; Jakobsen, Jarl A.

    1996-04-15

    Purpose: To examine the effect of an ultrasound contrast medium (UCM), Infoson, on Doppler examination of stenotic arteries. Methods: Stenoses were created in the common carotid artery of six piglets, and examined with spectral Doppler and color Doppler imaging during UCM infusion in the left ventricle. Results: UCM caused a mean increase in recorded maximal systolic and end-diastolic velocities of 5% and 6%, respectively, while blood flow remained constant. Increased spectral intensity with UCM was accompanied by spectral broadening. Reduction of spectral intensity by adjustment of Doppler gain counteracted the velocity effects and the spectral broadening. With color Doppler, UCM caused dose-dependent color artifacts outside the artery. Flow in narrow stenoses could be visualized with UCM. Conclusion: The effects of UCM on velocity measurements were slight, and were related to changes in spectral intensity. With color Doppler, UCM may facilitate flow detection, but color artifacts may interfere.

  11. Doppler Lidar (DL) Handbook

    SciTech Connect

    Newsom, RK

    2012-02-13

    The Doppler lidar (DL) is an active remote sensing instrument that provides range- and time-resolved measurements of radial velocity and attenuated backscatter. The principle of operation is similar to radar in that pulses of energy are transmitted into the atmosphere; the energy scattered back to the transceiver is collected and measured as a time-resolved signal. From the time delay between each outgoing transmitted pulse and the backscattered signal, the distance to the scatterer is inferred. The radial or line-of-sight velocity of the scatterers is determined from the Doppler frequency shift of the backscattered radiation. The DL uses a heterodyne detection technique in which the return signal is mixed with a reference laser beam (i.e., local oscillator) of known frequency. An onboard signal processing computer then determines the Doppler frequency shift from the spectra of the heterodyne signal. The energy content of the Doppler spectra can also be used to determine attenuated backscatter.

  12. A High-Frequency High Frame Rate Duplex Ultrasound Linear Array Imaging System for Small Animal Imaging

    PubMed Central

    Zhang, Lequan; Xu, Xiaochen; Hu, Changhong; Sun, Lei; Yen, Jesse T.; Cannata, Jonathan M.; Shung, K. Kirk

    2010-01-01

    High-frequency (HF) ultrasound imaging has been shown to be useful for non-invasively imaging anatomical structures of the eye and small animals in biological and pharmaceutical research, achieving superior spatial resolution. Cardiovascular research utilizing mice requires not only real-time B-scan imaging, but also ultrasound Doppler to evaluate both anatomy and blood flow of the mouse heart. This paper reports the development of a high frequency ultrasound duplex imaging system capable of both B-mode imaging and Doppler flow measurements, using a 64-element linear array. The system included a HF pulsed-wave Doppler module, a 32-channel HF B-mode imaging module, a PC with a 200 MS/s 14-bit A/D card, and real-time LabView software. A 50dB signal-to-noise ratio (SNR) and a depth of penetration of larger than 12 mm were achieved using a 35 MHz linear array with 50 μm pitch. The two-way beam widths were determined to be 165 μm to 260 μm and the clutter energy to total energy ratio (CTR) were 9.1 dB to 12 dB, when the array was electronically focused at different focal points at depths from 4.8 mm to 9.6 mm. The system is capable of acquiring real-time B-mode images at a rate greater than 400 frames per second (fps) for a 4.8 × 13 mm field of view, using a 30 MHz 64-element linear array with 100 μm pitch. Sample in vivo cardiac high frame rate images and duplex images of mouse hearts are shown to assess its current imaging capability and performance for small animals. PMID:20639149

  13. Perfusion imaging with non-contrast ultrasound

    NASA Astrophysics Data System (ADS)

    Tierney, Jaime E.; Dumont, Douglas M.; Byram, Brett C.

    2016-04-01

    A Doppler ultrasound clutter filter that enables estimation of low velocity blood flow could considerably improve ultrasound as a tool for clinical diagnosis and monitoring, including for the evaluation of vascular diseases and tumor perfusion. Conventional Doppler ultrasound is currently used for visualizing and estimating blood flow. However, conventional Doppler is limited by frame rate and tissue clutter caused by involuntary movement of the patient or sonographer. Spectral broadening of the clutter due to tissue motion limits ultrasound's ability to detect blood flow less than about 5mm/s at an 8MHz center frequency. We propose a clutter filtering technique that may increase the sensitivity of Doppler measurements to at least as low as 0.41mm/s. The proposed filter uses an adaptive demodulation scheme that decreases the bandwidth of the clutter. To test the performance of the adaptive demodulation method at removing sonographer hand motion, six volunteer subjects acquired data from a basic quality assurance phantom. Additionally, to test initial in vivo feasibility, an arterial occlusion reactive hyperemia study was performed to assess the efficiency of the proposed filter at preserving signals from blood velocities 2mm/s or greater. The hand motion study resulted in initial average bandwidths of 577Hz (28.5mm/s), which were decreased to 7.28Hz (0.36mm/s) at -60 dB at 3cm using our approach. The in vivo power Doppler study resulted in 15.2dB and 0.15dB dynamic ranges between the lowest and highest blood flow time points for the proposed filter and conventional 50Hz high pass filter, respectively.

  14. Remote television viewing: an ultrasound teaching device.

    PubMed

    Raskin, M M; Vining, P E

    1979-07-01

    Remote viewing of ultrasound scans facilitates assessment of a student's technique while minimizing anxiety for both him and the patient. This method may also be effective for the busy physician who must monitor several procedures at the same time.

  15. High definition ultrasound imaging for battlefield medical applications

    SciTech Connect

    Kwok, K.S.; Morimoto, A.K.; Kozlowski, D.M.; Krumm, J.C.; Dickey, F.M.; Rogers, B; Walsh, N.

    1996-06-23

    A team has developed an improved resolution ultrasound system for low cost diagnostics. This paper describes the development of an ultrasound based imaging system capable of generating 3D images showing surface and subsurface tissue and bone structures. We include results of a comparative study between images obtained from X-Ray Computed Tomography (CT) and ultrasound. We found that the quality of ultrasound images compares favorably with those from CT. Volumetric and surface data extracted from these images were within 7% of the range between ultrasound and CT scans. We also include images of porcine abdominal scans from two different sets of animal trials.

  16. Cosmology with Doppler lensing

    NASA Astrophysics Data System (ADS)

    Bacon, David J.; Andrianomena, Sambatra; Clarkson, Chris; Bolejko, Krzysztof; Maartens, Roy

    2014-09-01

    Doppler lensing is the apparent change in object size and magnitude due to peculiar velocities. Objects falling into an overdensity appear larger on its near side, and smaller on its far side, than typical objects at the same redshifts. This effect dominates over the usual gravitational lensing magnification at low redshift. Doppler lensing is a promising new probe of cosmology, and we explore in detail how to utilize the effect with forthcoming surveys. We present cosmological simulations of the Doppler and gravitational lensing effects based on the Millennium simulation. We show that Doppler lensing can be detected around stacked voids or unvirialized overdensities. New power spectra and correlation functions are proposed which are designed to be sensitive to Doppler lensing. We consider the impact of gravitational lensing and intrinsic size correlations on these quantities. We compute the correlation functions and forecast the errors for realistic forthcoming surveys, providing predictions for constraints on cosmological parameters. Finally, we demonstrate how we can make 3D potential maps of large volumes of the Universe using Doppler lensing.

  17. [Color Doppler sonography of focal abdominal lesions].

    PubMed

    Licanin, Zoran; Lincender, Lidija; Djurović, V; Salihefendić, Nizama; Smajlović, Fahrudin

    2004-01-01

    Color Doppler sonography (CDS--spectral, color and power), harmonic imaging techniques (THI, PHI), possibility of 3D analysis of picture, usage of contrast agents, have raised the values of ultrasound as a diagnostic method to a very high level. THI--non-linear gray scale modality, is based on the processing of higher reflected frequencies, that has improved a picture resolution, which is presented with less artifacts and limiting effects of obesity and gases. Ultrasound contrast agents improve analysis of micro and macro circulation of the examined area, and with the assessment of velocity of supply in ROI (wash in), distribution and time of signal weakening (wash out), are significantly increasing diagnostic value of ultrasound. Besides the anatomical and topographic presentation of examined region (color, power), Color Doppler sonography gives us haemodynamic-functional information on vascularisation of that region, as well as on pathologic vascularisation if present. Avascular aspect of a focal pathologic lesion corresponds to a cyst or haematoma, while coloration and positive spectral curve discover that anechogenic lesions actually represents aneurysms, pseudoaneurysms or AVF. In local inflammatory lesion, abscess in an acute phase, CDS shows first increased, and then decreased central perfusion, while in a chronic phase, a pericapsular vascularisation is present. Contribution of CDS in differentiation of hepatic tumors (hemangioma, HCC and metastasis) is very significant. Central color dots along the peripheral blood vessels and the blush phenomenon are characteristics of capillary hemangioma, peritumoral vascular ring "basket" of HCC, and "detour" sign of metastasis. The central artery, RI from 0.45 to 0.60 and radial spreading characterize FNH. Hepatic adenoma is characterized by an intratumoral vein, and rarely by a vascular hallo. Further on, blood velocity in tumor defined by Color Doppler, distinguishes malignant from benign lesion, where 40 cm/s is a

  18. 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.

  19. Doppler Lidar Wind Value-Added Product

    SciTech Connect

    Newsom, R. K.; Sivaraman, C.; Shippert, T. R.; Riihimaki, L. D.

    2015-07-01

    Wind speed and direction, together with pressure, temperature, and relative humidity, are the most fundamental atmospheric state parameters. Accurate measurement of these parameters is crucial for numerical weather prediction. Vertically resolved wind measurements in the atmospheric boundary layer are particularly important for modeling pollutant and aerosol transport. Raw data from a scanning coherent Doppler lidar system can be processed to generate accurate height-resolved measurements of wind speed and direction in the atmospheric boundary layer.

  20. Effect of deviation from plane wave conditions on the Doppler spectrum from an ultrasonic blood flow detector.

    PubMed

    Ata, O W; Fish, P J

    1991-09-01

    Deviation from plane wave conditions within the ultrasound beam of a Doppler blood flow detector leads to a non-linear relationship between the phase angle of the back-scattered signal and the scatterer position. This in turn leads to frequency modulation of the Doppler signal and an increase in the Doppler spectrum width. The relationship between the ultrasound beam and the observed signal spectrum has been investigated by employing a computer-based model of the ultrasound field which enabled the calculation of: 1, pressure (amplitude and phase angle) field distributions from plane disc and focused transducers with unapodized and apodized aperture field distributions; 2, the Doppler signal from a scatterer moving through the field; and 3, the spectrum of this signal. The increase in spectral width resulting from deviations from plane wave conditions was calculated by comparing this spectrum with that of the signal from which frequency modulation had been removed.

  1. 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

  2. Unsupervised dealiasing and denoising of color-Doppler data.

    PubMed

    Muth, Stéphan; Dort, Sarah; Sebag, Igal A; Blais, Marie-Josée; Garcia, Damien

    2011-08-01

    Color Doppler imaging (CDI) is the premiere modality to analyze blood flow in clinical practice. In the prospect of producing new CDI-based tools, we developed a fast unsupervised denoiser and dealiaser (DeAN) algorithm for color Doppler raw data. The proposed technique uses robust and automated image post-processing techniques that make the DeAN clinically compliant. The DeAN includes three consecutive advanced and hands-off numerical tools: (1) statistical region merging segmentation, (2) recursive dealiasing process, and (3) regularized robust smoothing. The performance of the DeAN was evaluated using Monte-Carlo simulations on mock Doppler data corrupted by aliasing and inhomogeneous noise. Fifty aliased Doppler images of the left ventricle acquired with a clinical ultrasound scanner were also analyzed. The analytical study demonstrated that color Doppler data can be reconstructed with high accuracy despite the presence of strong corruption. The normalized RMS error on the numerical data was less than 8% even with signal-to-noise ratio as low as 10dB. The algorithm also allowed us to recover highly reliable Doppler flows in clinical data. The DeAN is fast, accurate and not observer-dependent. Preliminary results showed that it is also directly applicable to 3-D data. This will offer the possibility of developing new tools to better decipher the blood flow dynamics in cardiovascular diseases.

  3. Functional Doppler optical coherence tomography for cortical blood flow imaging

    NASA Astrophysics Data System (ADS)

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

    2010-02-01

    Optical methods have been widely used in basic neuroscience research to study the cerebral blood flow dynamics in order to overcome the low spatial resolution associated with magnetic resonance imaging and positron emission tomography. Although laser Doppler imaging and laser speckle imaging can map out en face cortical hemodynamics and columns, depth resolution is not available. Two-photon microscopy has been used for mapping cortical activity. However, flow measurement requires fluorescent dye injection, which can be problematic. The noninvasive and high resolution tomographic capabilities of optical coherence tomography make it a promising technique for mapping depth resolved cortical blood flow. Here, we present a functional Doppler optical coherence tomography (OCT) imaging modality for quantitative evaluation of cortical blood flow in a mouse model. Fast, repeated, Doppler OCT scans across a vessel of interest were performed to record flow dynamic information with a high temporal resolution of the cardiac cycles. Spectral Doppler analysis of continuous Doppler images demonstrates how the velocity components and longitudinally projected flow-volume-rate change over time, thereby providing complementary temporal flow information to the spatially distributed flow information of Doppler OCT. The proposed functional Doppler OCT imaging modality can be used to diagnose vessel stenosis/blockage or monitor blood flow changes due to pharmacological agents/neuronal activities. Non-invasive in-vivo mice experiments were performed to verify the capabilities of function Doppler OCT.

  4. Laser Doppler dust devil measurements

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

    A scanning laser doppler velocimeter (SLDV) system was used to detect, track, and measure the velocity flow field of naturally occurring tornado-like flows (dust devils) in the atmosphere. A general description of the dust devil phenomenon is given along with a description of the test program, measurement system, and data processing techniques used to collect information on the dust devil flow field. The general meteorological conditions occurring during the test program are also described, and the information collected on two selected dust devils are discussed in detail to show the type of information which can be obtained with a SLDV system. The results from these measurements agree well with those of other investigators and illustrate the potential for the SLDV in future endeavors.

  5. Ultrasound - Breast

    MedlinePlus

    ... discharge) and to characterize potential abnormalities seen on mammography or breast magnetic resonance imaging (MRI). Ultrasound imaging ... supply in breast lesions . Supplemental Breast Cancer Screening Mammography is the only screening tool for breast cancer ...

  6. Thyroid ultrasound

    MedlinePlus

    ... Performed Ultrasound is a painless method that uses sound waves to create images of the inside of the ... neck to help with the transmission of the sound waves. Next, the technician moves a wand, called a ...

  7. Abdominal Ultrasound

    MedlinePlus

    ... collects the sounds that bounce back and a computer then uses those sound waves to create an ... Ultrasound scanners consist of a console containing a computer and electronics, a video display screen and a ...

  8. Obstetrical Ultrasound

    MedlinePlus

    ... collects the sounds that bounce back and a computer then uses those sound waves to create an ... Ultrasound scanners consist of a console containing a computer and electronics, a video display screen and a ...

  9. [Interventional ultrasound].

    PubMed

    Blázquez Sánchez, N; Fernández Canedo, I; Valdés Vilches, L; de Troya Martín, M

    2015-11-01

    High-frequency ultrasound has become increasingly used in dermatology. This technique is accessible, non-invasive, and rapid and provides information in real time. Consequently, it has become of great diagnostic value in dermatology. However, high-frequency ultrasound also has a promising future as a complementary technique in interventional diagnostic procedures, even though its application in this field has been little studied by dermatologists. PMID:26895944

  10. High-overtone self-focusing acoustic transducers for high-frequency ultrasonic Doppler.

    PubMed

    Zhu, Jie; Lee, Chuangyuan; Kim, Eun Sok; Wu, Dawei; Hu, Changhong; Zhou, Qifa; Shung, K Kirk; Wang, Gaofeng; Yu, Hongyu

    2010-05-01

    This work reports the potential use of high-overtone self-focusing acoustic transducers for high-frequency ultrasonic Doppler. By using harmonic frequencies of a thick bulk Lead Zirconate Titanate (PZT) transducer with a novel air-reflector Fresnel lens, we obtained strong ultrasound signals at 60 MHz (3rd harmonic) and 100 MHz (5th harmonic). Both experimental and theoretical analysis has demonstrated that the transducers can be applied to Doppler systems with high frequencies up to 100 MHz.

  11. Vascular ultrasound for atherosclerosis imaging

    PubMed Central

    de Korte, Chris L.; Hansen, Hendrik H. G.; van der Steen, Anton F. W.

    2011-01-01

    Cardiovascular disease is a leading cause of death in the Western world. Therefore, detection and quantification of atherosclerotic disease is of paramount importance to monitor treatment and possible prevention of acute events. Vascular ultrasound is an excellent technique to assess the geometry of vessel walls and plaques. The high temporal as well as spatial resolution allows quantification of luminal area and plaque size and volume. While carotid arteries can be imaged non-invasively, scanning of coronary arteries requires invasive intravascular catheters. Both techniques have already demonstrated their clinical applicability. Using linear array technology, detection of disease as well as monitoring of pharmaceutical treatment in carotid arteries are feasible. Data acquired with intravascular ultrasound catheters have proved to be especially beneficial in understanding the development of atherosclerotic disease in coronary arteries. With the introduction of vascular elastography not only the geometry of plaques but also the risk for rupture of plaques might be identified. These so-called vulnerable plaques are frequently not flow-limiting and rupture of these plaques is responsible for the majority of cerebral and cardiac ischaemic events. Intravascular ultrasound elastography studies have demonstrated a high correlation between high strain and vulnerable plaque features, both ex vivo and in vivo. Additionally, pharmaceutical intervention could be monitored using this technique. Non-invasive vascular elastography has recently been developed for carotid applications by using compound scanning. Validation and initial clinical evaluation is currently being performed. Since abundance of vasa vasorum (VV) is correlated with vulnerable plaque development, quantification of VV might be a unique tool to even prevent this from happening. Using ultrasound contrast agents, it has been demonstrated that VV can be identified and quantified. Although far from routine

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

    SciTech Connect

    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 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.

  13. Ultrasound diagnosis of uterine myomas.

    PubMed

    Fascilla, Fabiana D; Cramarossa, Paola; Cannone, Rossella; Olivieri, Claudiana; Vimercati, Antonella; Exacoustos, Caterina

    2016-06-01

    Myomas represent a large part of benign gynecological pathology, widely spread in fertile female population. First step to diagnose fibroids is ultrasound (US) that can be 2-dimensional (2D), 3-dimensional (3D), Color Doppler (CD) and sonohysterography (SHG). This review develops according to MUSA's sonographic features (Morphological Uterus Sonographic Assessment). One of the main topic of interest for ultrasonographer today is endo/myometrial junctional zone (JZ), because it may be useful to discern a diagnosis of myoma and adenomyosis. Another important aspect of ultrasound is the analysis of vascularization in front of a uterine lesion. Indeed, vascular pattern can be used to make differential diagnosis between myoma-adenomyosis and leiomyosarcomas. Myomas should be described accurately according to sonographic guidelines. Sonographic features correlated with symptoms should guide an appropriate surgical or medical treatment. PMID:27014801

  14. [Ultrasound imaging of Dupuytren's contracture].

    PubMed

    Créteur, V; Madani, A; Gosset, N

    2010-06-01

    Dupuytren's contracture is characterized by two underlying lesions, nodules and cords. These involve the palmar fascia at the distal palmar crease, especially at the level of the third and fourth rays with progressive disabling finger contracture. The superficial palmar aponeurosis appears as a thin echogenic lamellar structure overlying the flexor tendons. The demonstration of hypoechoic bands adhering to the marging of the flexor tendons and deep surface of the dermis appears to be pathognomonic of the disease. Compared to tendons, early nodules are hypoechoic and typically hypervascular whereas older nodules are iso- to hyperechoic, without hypervascular Doppler signal. Ultrasound can sometimes demonstrate arterial encasement by fibrous or scarring tissue. Ultrasound therefore is very useful for the differential diagnosis of pathologies involving the palmar surface of the hand, for the early detection of Dupuytren's contracture, and for the detection of complication, especially vascular. These data may have an impact on management. PMID:20808269

  15. Role of Gray Scale, Color Doppler and Spectral Doppler in Differentiation Between Malignant and Benign Thyroid Nodules

    PubMed Central

    Palaniappan, Manoj Kumar; Aiyappan, Senthil Kumar

    2016-01-01

    Introduction High resolution ultrasound is the most sensitive imaging test available for the examination of the thyroid gland and due to increase in use of ultrasound more incidental thyroid nodules are diagnosed. In this study we try to establish the specific grayscale, color and spectral Doppler characteristics of malignant and benign thyroid nodules. Aim To determine the specific gray scale characteristics, angioarchitecture and cut-off values of Doppler indices of malignant and benign thyroid nodules. To assess the efficacy of grayscale, Doppler and combined conventional and Doppler using defined criteria in differentiating malignant from benign nodules. Materials and Methods We prospectively examined 194 thyroid nodules which were confirmed on FNAC. Each nodule was described according to size, number, contents, echogenicity, margins, halo, shape, calcification, local infiltration and lymphnode enlargement. Vascularity, RI and PI values of each nodule were assessed on Doppler. Each nodule was characterized as benign, indeterminate or malignant based on grayscale and Doppler characteristics. Cut-off RI and PI values for malignant thyroid nodules were obtained by ROC. Results Out of 194 nodules, 151 nodules were benign and 43 nodules were malignant. Significant relationship was observed between malignancy and hypoechogenicity, irregular margins, taller than wide, thick incomplete halo, micro calcifications, lymphnode enlargement and local infiltration. Intranodular vascularity was a significant criterion to suggest malignancy in thyroid nodules on color Doppler. Malignant nodules had a mean RI of 0.73 and mean PI of 1.3 which were significantly higher than the benign nodules. Accuracy of detecting malignant thyroid nodules by combining gray scale and Doppler is higher than either of them alone. Conclusion Using specific morphological pattern recognition features like microcalcifications, hypoechogenicity, taller than wide, irregular thick halo, lymphadenopathy

  16. Reduction of coherent scattering noise with multiple receiver Doppler.

    PubMed

    Jones, Steven A; Krishnamurthy, Kiran

    2002-05-01

    Doppler ultrasound (US) velocity estimates are inherently subject to error as a result of both Doppler ambiguity and coherent scattering. The coherent scattering error is a result of changes in the phase of the returned echo as particles enter and leave the sample volume. This phase depends on the distance from the transmitter to the scatterer and then to the receiver. This distance, in turn, depends on the angle of the receiver. A numerical simulation has been used to determine whether velocity estimates obtained from receiver probes at different angles are independent of one another. If so, then it is possible to obtain an improved velocity estimate from the combination of several receivers at different angles. The simulation results show that the cross-correlation between velocity estimates is reduced to 0.3 when receiver probes are oriented 5 degrees apart. These results suggest a new Doppler method that can significantly reduce velocity estimation error.

  17. Cranial Ultrasound/Head Ultrasound

    MedlinePlus

    ... collects the sounds that bounce back and a computer then uses those sound waves to create an ... Ultrasound scanners consist of a console containing a computer and electronics, a video display screen and a ...

  18. Physical principles of microbubbles for ultrasound imaging and therapy.

    PubMed

    Stride, Eleanor

    2015-01-01

    Microbubble ultrasound contrast agents have been in clinical use for more than two decades, during which time their range of applications has increased to encompass echocardiography, Doppler enhancement, perfusion studies and molecular imaging, as well as a number of therapeutic applications, including drug delivery, gene therapy, high-intensity focused ultrasound treatments and sonothrombolysis. The aim of this article is to review the different types of microbubble agents, their physical behaviours and the mechanisms underlying their effectiveness in imaging and therapeutic applications.

  19. Physical principles of microbubbles for ultrasound imaging and therapy.

    PubMed

    Stride, Eleanor

    2009-01-01

    Microbubble ultrasound contrast agents have been in clinical use for more than two decades, during which time their range of applications has increased to encompass echocardiography, Doppler enhancement, perfusion studies and molecular imaging, as well as a number of therapeutic applications including drug delivery, gene therapy, high-intensity focused ultrasound treatments and sonothrombolysis. The aim of this article is to review the different types of microbubble agent, their physical behaviour and the mechanisms underlying their effectiveness in imaging and therapeutic applications.

  20. Serial color Doppler flow of uterine vasculature combined with serum beta-hCG measurements for improved monitoring of patients with gestational trophoblastic disease. A preliminary report.

    PubMed

    Maymon, R; Schneider, D; Shulman, A; Bukowsky, I; Weinraub, Z

    1996-01-01

    Weekly serum beta-hCG measurements and transvaginal ultrasound scans coupled with color Doppler flow were performed on 8 patients with hydatidiform mole. Two patients later developed persistent trophoblastic disease, necessitating chemotherapy. The correlation coefficients between Doppler flow indices, systolic-diastolic (S/D) ratio and pulsatility index (PI) with log beta-hCG were -0.96 and -0.97, respectively. The weekly S/D and PI indices were plotted on an individual curve. Only the 2 patients who developed persistent gestational trophoblastic disease had PI index levels of < or = 1.5 as early as 2 weeks after molar evacuation. At that stage their serum beta-hCG levels were not different from some of the other patients. In this preliminary report, the regression of the disease could be reliably assessed by observing the changes in low resistance flow which paralleled the gradual decrements in serial beta-hCG levels. Thus, the contribution of this noninvasive imaging technique encourages the authors to further investigate Doppler flow monitoring among a larger sample of patients suffering from various gestational trophoblastic diseases.

  1. In vitro in-stent restenoses evaluated by 3D ultrasound.

    PubMed

    Lécart, Myriam; Cardinal, Marie-Hélène Roy; Qin, Zhao; Soulez, Gilles; Cloutier, Guy

    2009-02-01

    The purpose of this study was to quantify in-stent restenoses with 3D B mode and power Doppler ultrasound (U.S.) imaging. In-stent restenoses were mimicked with vascular phantoms in which a nonferromagnetic prototype stent (Boston Scientific) and a ferromagnetic clinical stainless steel stent (Palmaz P295) were embedded. Each phantom had an 80% in-stent stenosis and a 75% stenosis located outside the stent. These phantoms were compared to a reference phantom reproducing both stenoses without stent. Data sets of 2D cross-sectional U.S. images were acquired in freehand scanning using a magnetic sensor attached to the U.S. probe and in mechanical linear scanning with the probe attached to a step motor device. Each 2D image was automatically segmented before 3D reconstruction of the vessel. Results indicate that the reference phantom (without stent) was accurately assessed with errors below 1.8% for the 75% stenosis and 3.2% for the 80% stenosis in both B mode and power Doppler for the two scanning methods. The 80% in-stent stenoses in Boston Scientific and Palmaz stents were, respectively, evaluated at 73.8 (+/-3.2)% and 75.8 (+/- 3)% in B mode and at 82 (+/- 2.5)% and 86.2 (+/- 6.4)% in power Doppler when freehand scans were used. For comparison, when linear scans were selected, in-stent stenoses in the Boston Scientific or Palmaz stent were, respectively, evaluated at 77.4 (+/- 2.0)% and 73.8 (+/- 2.5)% in B mode and at 87.0 (+/- 1.3)% and 85.6 (+/- 5.8)% in power Doppler. To conclude, 3D freehand U.S. is a valuable method to quantify in-stent restenoses, particularly in B mode. It is thus hoped that, in the clinical setting, noninvasive 3D U.S. may provide sufficient precision to grade in-stent restenoses. PMID:19291990

  2. Laser Doppler imaging: usefulness in chronic pain medicine.

    PubMed

    Grothusen, John R; Schwartzman, Robert J

    2011-01-01

    Sympathetic nervous system dysfunction is thought to be a factor in neuropathic pain conditions such as Complex Regional Pain Syndrome and in vascular conditions such as Raynaud's phenomenon. Laser Doppler fluxmetry has been used as a fast non-invasive method to quantify changes in skin capillary blood flow which reflect activation of sympathetically mediated vasoconstriction of the arterioles that supply the capillaries. Studies of dynamic change of skin capillary blood flow with sympathetic activation such as cold or inspiratory gasp have generally used single point laser Doppler systems where the probe is in contact with the skin. The results are a single line tracing representing the capillary flow at a single point on the skin a few millimeters in diameter. Laser Doppler imaging (moorLDI laser Doppler imager, Moor Instruments Ltd.) allows for non-contact recording of skin blood flow of an area as large as 50 centimeters square with a resolution of 256 by 256 pixels and 4 milliseconds per pixel. Most work with laser Doppler imaging has studied changes that occur between successive scans. We have found it useful to look at changes that occur during a scan. In this way we obtain data that is comparable to the time resolution of single point laser Doppler methods, but with the larger spatial information that is available with laser Doppler imaging. We present a small series of case reports in which inspiratory gasp during laser Doppler imaging was able to provide quick, useful and unequivocal clinical information regarding the status of regional bilateral skin capillary response to sympathetic activation. This may be useful for distinguishing sympathetically mediated from sympathetically independent pain. We believe the methods described may provide the basis for future quantitative studies similar to those that use single point laser Doppler methods.

  3. Contrast-enhanced ultrasound of the spleen.

    PubMed

    Omar, Asha; Freeman, Simon

    2016-02-01

    Abnormalities in the spleen are less common than in most other abdominal organs. However, they will be regularly encountered by ultrasound practitioners, who carefully evaluate the spleen in their abdominal ultrasound studies. Conventional grey scale and Doppler ultrasound are frequently unable to characterise focal splenic abnormalities; even when clinical and laboratory information is added to the ultrasound findings, it is often not possible to make a definite diagnosis. Contrast-enhanced ultrasound (CEUS) is easy to perform, inexpensive, safe and will usually provide valuable additional information about splenic abnormalities, allowing a definitive or short differential diagnosis to be made. It also identifies those lesions that may require further imaging or biopsy, from those that can be safely dismissed or followed with interval ultrasound imaging. CEUS is also indicated in confirming the nature of suspected accessory splenic tissue and in selected patients with abdominal trauma. This article describes the CEUS examination technique, summarises the indications for CEUS and provides guidance on interpretation of the CEUS findings in splenic ultrasound.

  4. Comparison of transcranial ultrasound and cranial MRI in evaluations of brain injuries from neonatal asphyxia.

    PubMed

    Shen, Wei; Pan, Jia-Hua; Chen, Wei-Dong

    2015-01-01

    Full-term infants with early-stage brain injuries from asphyxia were examined with two-dimensional ultrasound and color Doppler to assess the use of ultrasound in evaluating early brain injuries after neonatal asphyxia. The sonographic features of ultrasound and color Doppler were compared to those of magnetic resonance imaging (MRI). Ultrasound was used to monitor the brain parenchyma, lateral ventricles, and cerebral hemodynamics in the asphyxia group and full-term control group 24, 48, and 72 h after birth. MRI and diffusion-weight imaging (DWI) were performed within 72 h. Cerebral edema changes were most obvious with ultrasound within 48 h of asphyxia, while the cerebral hemodynamic changes were most obvious within 24 h. These results suggested that ultrasound detected early cerebral edema better than MRI did. PMID:26770434

  5. Laser Doppler projection tomography.

    PubMed

    Zeng, Yaguang; Xiong, Ke; Lu, Xuanlong; Feng, Guanping; Han, Dingan; Wu, Jing

    2014-02-15

    We propose a laser Doppler projection tomography (LDPT) method to obtain visualization of three-dimensional (3D) flowing structures. With LDPT, the flowing signal is extracted by a modified laser Doppler method, and the 3D flowing image is reconstructed by the filtered backprojection algorithm. Phantom experiments are performed to demonstrate that LDPT is able to obtain 3D flowing structure with higher signal-to-noise ratio and spatial resolution. Our experiment results display its potentially useful application to develop 3D label-free optical angiography for the circulation system of live small animal models or microfluidic experiments.

  6. Doppler-based lateral motion tracking for optical coherence tomography.

    PubMed

    Weiss, Nicolás; van Leeuwen, Ton G; Kalkman, Jeroen

    2012-06-15

    Nonuniform lateral scanning of the probe beam in optical coherence tomography produces imaging artifacts and leads to a morphologically inaccurate representation of the sample. Here, we demonstrate a solution to this problem, which is based on the Doppler shift carried by the complex-valued depth-resolved scattering amplitude. Furthermore, we demonstrate the feasibility of Doppler flow velocity measurements in underlying flow channels while laterally scanning the imaging probe over large surfaces with arbitrary and varying velocity. Finally, we performed centimeters-long hand-held B-mode imaging of skin in vivo.

  7. Atmospheric probing by Doppler radar

    NASA Technical Reports Server (NTRS)

    Lhermitte, R. M.

    1969-01-01

    A survey is presented of the application of Doppler techniques to the study of atmospheric phenomena. Particular emphasis is placed on the requirement of adequate digital processing means for the Doppler signal and the Doppler data which are acquired at a very high rate. The need is discussed of a two or three Doppler method as an ultimate approach to the problem of observing the three-dimensional field of particle motion inside convective storms.

  8. Laser-diode based 10MHz photoacoustic Doppler flowmetry at 830 nm

    NASA Astrophysics Data System (ADS)

    Sheinfeld, Adi; Eyal, Avishay

    2012-02-01

    Photoacoustic Doppler Flowmetry has several potential advantages over its purely acoustical counterpart. The key ones are better inherent contrast and potential molecular information. It is therefore highly desired to continue to develop this modality into a viable complementary tool alongside with Doppler Ultrasound flowmetry. Working towards this goal we have constructed a Photoacoustic Doppler setup based on a combined pair of laser diodes at 830nm and a 10MHz focused acoustical transducer. Using tone-burst intensity modulation, depth-resolved Doppler spectrograms of a phantom vessel containing flowing suspension of carbon particles, were obtained. In order to investigate the conditions required for successful photoacoustic Doppler measurement in blood a k-space photoacoustic simulation was performed. It tested the photoacoustic response which is obtained for moving random spatial distributions of red blood cells and the effect of several parameters, such as particles density, ultrasonic frequency and optical spot size.

  9. Finnish Meteorological Institute Doppler Lidar

    SciTech Connect

    Ewan OConnor

    2015-03-27

    This doppler lidar system provides co-polar and cross polar attenuated backscatter coefficients,signal strength, and doppler velocities in the cloud and in the boundary level, including uncertainties for all parameters. Using the doppler beam swinging DBS technique, and Vertical Azimuthal Display (VAD) this system also provides vertical profiles of horizontal winds.

  10. The Doppler Pendulum Experiment

    ERIC Educational Resources Information Center

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

    2011-01-01

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

  11. Photonic doppler velocimetry

    SciTech Connect

    Lowry, M E; Molau, N E; Sargis, P D; Strand, O T; Sweider, D

    1999-01-01

    We are developing a novel fiber-optic approach to laser Doppler velocimetry as a diagnostic for high explosives tests. Using hardware that was originally developed for the telecommunications industry, we are able to measure surface velocities ranging from centimeters per second to kilometers per second. Laboratory measurements and field trials have shown excellent agreement with other diagnostics.

  12. [MRI and CT-scan in presumed benign ovarian tumors].

    PubMed

    Thomassin-Naggara, I; Bazot, M

    2013-12-01

    Radiological examinations are required for the assessment of complex or indeterminate ovarian masses, mainly using MRI and CT-scan. MRI provides better tissue characterization than Doppler ultrasound or CT-scan (LE2). Pelvic MRI is recommended in case of an indeterminate or complex ovarian ultrasonographic mass (grade B). The protocol of a pelvic MRI should include morphological T1 and T2 sequences (grade B). In case of solid portion, perfusion and diffusion sequences are recommended (grade C). In case of doubt about the diagnosis of ovarian origin, pelvic MRI is preferred over the CT-scan (grade C). MRI is the technique of choice for the difference between functional and organic ovarian lesion diagnosis (grade C). It can be useful in case of clinical diagnostic uncertainty between polycystic ovary syndrome and ovarian hyperstimulation and multilocular ovarian tumor syndrome (grade C). No MRI classification for ovarian masses is currently validated. The establishment of a presumption of risk of malignancy is required in a MRI report of adnexal mass with if possible a guidance on the histological diagnosis. In the absence of clinical or sonographic diagnosis, pelvic CT-scan is recommended in the context of acute painful pelvic mass in non-pregnant patients (grade C). It specifies the anomalies and allows the differential diagnosis with digestive and urinary diseases (LE4). Given the lack of data in the literature, the precautionary principle must be applied to the realization of a pelvic MRI in a pregnant patient. A risk-benefit balance should be evaluated case by case by the clinician and the radiologist and information should be given to the patient. In an emergency situation during pregnancy, pelvic MRI is an alternative to CT-scan for the exploration of acute pelvic pain in case of uncertain sonographic diagnosis (grade C).

  13. 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

  14. 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.

  15. Consider ultrasound first for imaging the female pelvis.

    PubMed

    Benacerraf, Beryl R; Abuhamad, Alfred Z; Bromley, Bryann; Goldstein, Steven R; Groszmann, Yvette; Shipp, Thomas D; Timor-Tritsch, Ilan E

    2015-04-01

    Ultrasound technology has evolved dramatically in recent years and now includes applications such as 3-dimensional volume imaging, real-time evaluation of pelvic organs (simultaneous with the physical examination), and Doppler blood flow mapping without the need for contrast, which makes ultrasound imaging unique for imaging the female pelvis. Among the many cross-sectional imaging techniques, we should use the most informative, less invasive, and less expensive modality to avoid radiation when possible. Hence, ultrasound imaging should be the first imaging modality used in women with pelvic symptoms.

  16. Color Doppler imaging of retinal diseases.

    PubMed

    Dimitrova, Galina; Kato, Satoshi

    2010-01-01

    Color Doppler imaging (CDI) is a widely used method for evaluating ocular circulation that has been used in a number of studies on retinal diseases. CDI assesses blood velocity parameters by using ultrasound waves. In ophthalmology, these assessments are mainly performed on the retrobulbar blood vessels: the ophthalmic, the central retinal, and the short posterior ciliary arteries. In this review, we discuss CDI use for the assessment of retinal diseases classified into the following: vascular diseases, degenerations, dystrophies, and detachment. The retinal vascular diseases that have been investigated by CDI include diabetic retinopathy, retinal vein occlusions, retinal artery occlusions, ocular ischemic conditions, and retinopathy of prematurity. Degenerations and dystrophies included in this review are age-related macular degeneration, myopia, and retinitis pigmentosa. CDI has been used for the differential diagnosis of retinal detachment, as well as the evaluation of retrobulbar circulation in this condition. CDI is valuable for research and is a potentially useful diagnostic tool in the clinical setting.

  17. Standardized ultrasound evaluation of carotid stenosis for clinical trials: University of Washington Ultrasound Reading Center

    PubMed Central

    2010-01-01

    Introduction Serial monitoring of patients participating in clinical trials of carotid artery therapy requires noninvasive precision methods that are inexpensive, safe and widely available. Noninvasive ultrasonic duplex Doppler velocimetry provides a precision method that can be used for recruitment qualification, pre-treatment classification and post treatment surveillance for remodeling and restenosis. The University of Washington Ultrasound Reading Center (UWURC) provides a uniform examination protocol and interpretation of duplex Doppler velocity measurements. Methods Doppler waveforms from 6 locations along the common carotid and internal carotid artery path to the brain plus the external carotid and vertebral arteries on each side using a Doppler examination angle of 60 degrees are evaluated. The UWURC verifies all measurements against the images and waveforms for the database, which includes pre-procedure, post-procedure and annual follow-up examinations. Doppler angle alignment errors greater than 3 degrees and Doppler velocity measurement errors greater than 0.05 m/s are corrected. Results Angle adjusted Doppler velocity measurements produce higher values when higher Doppler examination angles are used. The definition of peak systolic velocity varies between examiners when spectral broadening due to turbulence is present. Examples of measurements are shown. Discussion Although ultrasonic duplex Doppler methods are widely used in carotid artery diagnosis, there is disagreement about how the examinations should be performed and how the results should be validated. In clinical trails, a centralized reading center can unify the methods. Because the goals of research examinations are different from those of clinical examinations, screening and diagnostic clinical examinations may require fewer velocity measurements. PMID:20822530

  18. Ultrasound guided fluorescence tomography

    NASA Astrophysics Data System (ADS)

    Li, Baoqiang; Lesage, Frederic

    2012-10-01

    In this study, a hybrid-model imaging system combining fluorescence and ultrasound (US) was investigated with the motivation of providing structural priors towards improvement of fluorescence reconstruction. A single element transducer was scanned over the sample for anatomy. In the fluorescence part, a laser source was scanned over the sample with the emission received by an EMCCD camera. Synchronization was achieved by a pair of motorized linear stages. Structural information was derived from the US images and a profilometry and used to constrain reconstruction. In the reconstruction, we employed a GPU-based Monte Carlo simulation for forward modeling and a pattern-based method to take advantage of the huge dataset for the inverse problem. Performance of this system was validated with two phantoms with fluorophore inclusions. The results indicated that the fluorophore distribution could be accurately reconstructed. And the system has a potential for the future in-vivo study.

  19. 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…

  20. Fusion of color Doppler and magnetic resonance images of the heart.

    PubMed

    Wang, Chao; Chen, Ming; Zhao, Jiang-Min; Liu, Yi

    2011-12-01

    This study was designed to establish and analyze color Doppler and magnetic resonance fusion images of the heart, an approach for simultaneous testing of cardiac pathological alterations, performance, and hemodynamics. Ten volunteers were tested in this study. The echocardiographic images were produced by Philips IE33 system and the magnetic resonance images were generated from Philips 3.0-T system. The fusion application was implemented on MATLAB platform utilizing image processing technology. The fusion image was generated from the following steps: (1) color Doppler blood flow segmentation, (2) image registration of color Doppler and magnetic resonance imaging, and (3) image fusion of different image types. The fusion images of color Doppler blood flow and magnetic resonance images were implemented by MATLAB programming in our laboratory. Images and videos were displayed and saved as AVI and JPG. The present study shows that the method we have developed can be used to fuse color flow Doppler and magnetic resonance images of the heart. We believe that the method has the potential to: fill in information missing from the ultrasound or MRI alone, show structures outside the field of view of the ultrasound through MR imaging, and obtain complementary information through the fusion of the two imaging methods (structure from MRI and function from ultrasound). PMID:21656081