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Sample records for 30-mhz ultrasound array

  1. Realtime photoacoustic microscopy in vivo with a 30-MHz ultrasound array transducer

    Zemp, Roger J.; Song, Liang; Bitton, Rachel; Shung, K. Kirk; Wang, Lihong V.

    2008-01-01

    We present a novel high-frequency photoacoustic microscopy system capable of imaging the microvasculature of living subjects in realtime to depths of a few mm. The system consists of a high-repetition-rate Q-switched pump laser, a tunable dye laser, a 30-MHz linear ultrasound array transducer, a multichannel high-frequency data acquisition system, and a shared-RAM multi-core-processor computer. Data acquisition, beamforming, scan conversion, and display are implemented in realtime at 50 frame...

  2. All fiber sensor array for ultrasound sensing

    Gabai, Haniel; Steinberg, Idan; Eyal, Avishay

    2016-03-01

    The field of Optical Fiber Sensors (OFS) is gaining tremendous popularity in recent years. OFS natural immunity to electromagnetic disturbances, inherent biocompatibility and compactness making them highly attractive for ultrasound sensing. Moreover, their compatibility with photoacoustics can make them useful in situations where traditional piezoelectric probes are inadequate. However, the issue of multiplexing individual OFS into an array remains a challenging and costly task. In this work, we demonstrate a straightforward approach for multiplexing multiple broadband OFS for ultrasound sensing by exploiting most of the photoreceiver's bandwidth. The design is based on a recently developed system in which all sensing elements are connected to a single interrogator and to a single digitizing circuit. To mitigate aliasing, the system employs I/Q coherent detection. Synchronization of the sensor interrogation with the excitation enables very high repetition rates (kHz) making it ideal for applications where imaging of dynamic processes is desired.

  3. Breast ultrasound tomography with two parallel transducer arrays

    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.

  4. Phased-array ultrasound technology enhances accuracy of dual frequency ultrasound measurements - towards improved ultrasound bone diagnostics.

    Linder, Hans; Malo, Markus K H; Liukkonen, Jukka; Jurvelin, Jukka S; Töyräs, Juha

    2016-08-01

    Overlying soft tissues attenuate ultrasound backscattered from bone, complicating diagnostics of osteoporosis at the most important fracture sites. Dual-frequency ultrasound technique (DFUS) has been proposed to solve this problem through determination of thickness and composition of overlying soft tissue. This study applies DFUS technique for the first time with a phased-array transducer to investigate if the thickness of two interfering layers (oil and water) can be accurately determined in a variety of configurations. Results indicate that DFUS may be used with phased-array ultrasound systems, making them a suitable combination to consider in future development of clinical in vivo ultrasound methodologies. PMID:27187271

  5. Sub-array patterns of spherical-section phased array for high intensity focused ultrasound surgery

    WANG Xiaodong; WANG Xufei; LU Mingzhu; WAN Mingxi

    2005-01-01

    The sub-array field patterns of spherical-section phased array were implemented for noninvasive ultrasound surgery of liver-tumor. The sub-array approach included field calculation, pseudo-inverse method and genetic algorithm. The sub-arrays uncovered by ribs according to scanned images normally emitted ultrasound. The results from different sub-arrays demonstrated quite satisfied acoustic performances, which included qualified focus size and intensity level for ultrasound surgery with single-focus and multi-foci patterns. Moreover, the patterns could decrease power accumulation on the ribs, and avoid damaging normal tissues. Thus the sub-array method provides a promising tool for phased array ultrasound propagating through strong obstacles like human rib cage, and it may broaden the therapeutic area, make the surgery safer and more flexible.

  6. High-resolution medical ultrasound arrays using smart materials technology

    Bridger, Keith; Caldwell, Paul J.; Kuhn, Phillip; Winzer, Stephen R.

    1996-05-01

    Current ultrasound images have relatively low contrast (high levels of clutter) and resolution. Image quality could be dramatically improved if 2D ultrasound transducer arrays were available to perform the scans. These improvements would come from reducing clutter by eliminating target echoes that the beam width of a 1D array causes to be superimposed on a scan plane, and enhancing resolution by enabling the use of algorithms which correct the wavefront distortion introduced by propagation through tissue. The advent of 2D arrays would also enable 3D images to be displayed--eventually in real time. The fabrication of 2D ultrasound arrays is, however, very difficult. This stems from the acoustic requirements of the array (aperture, pitch and element size) which combine together to dictate large numbers (> 1000) of very-low capacitance (capacitance and impedance mismatch. This paper will show how the development of composite smart materials involving the integration of electromechanical elements with electronics is being extended to the development of relatively-inexpensive high-sensitivity 2D ultrasound arrays.

  7. High-frequency synthetic ultrasound array incorporating an actuator

    Ritter, Timothy A.; Shrout, Thomas R.; Shung, K. Kirk

    2001-05-01

    Ultrasound imaging at frequencies above 20 MHz relies almost exclusively on single-element transducers. IN order to apply array technology at these frequencies, several practical problems must be solved, including spatial scale and fabrication limitations, low device capacitance, and lack of a hardware beamformer. One method of circumventing these problems is to combine an array, an actuator, and a synthetic aperture software beamformer. The array can use relatively wide elements spaced on a coarse pitch. The actuator is used to move the array in short steps (less than the element pitch), and pulse-echo data is acquired at intermediate sample positions. The synthetic aperture beamformer reconstructs the image from the pulse-echo data. A 50 MHz example is analyzed in detail. Estimates of signal-to-noise reveal performance comparable to a standard phased array; furthermore, the actuated array requires half the number of elements, the elements are 8x wider, and only one channel is required. Simulated three-dimensional point spread functions demonstrate side lobe levels approaching - 40dB and main beam widths of 50 to 100 microns. A 50 MHz piezo-composite array design has been tested which displays experimental bandwidth of 70% while maintaining high sensitivity. Individual composite sub-elements are 18 microns wide. Once this array is integrated with a suitable actuator, it is anticipated that a tractable method of imaging with high frequency arrays will result.

  8. Ultrasound cylindrical phased array for transoesophageal thermal therapy: initial studies

    Melodelima, David [INSERM, Unite 556, 151 Cours Albert Thomas, 69424 Lyon (France); Lafon, Cyril [INSERM, Unite 556, 151 Cours Albert Thomas, 69424 Lyon (France); Prat, Frederic [Centre Hospitalier Bicetre, 78 Avenue General Leclerc, 94275 Le Kremlin Bicetre (France); Birer, Alain [INSERM, Unite 556, 151 Cours Albert Thomas, 69424 Lyon (France); Cathignol, Dominique [INSERM, Unite 556, 151 Cours Albert Thomas, 69424 Lyon (France)

    2002-12-07

    This work was undertaken to investigate the feasibility of constructing a cylindrical phased array composed of 64 elements spread around the periphery (OD 10.6 mm) for transoesophageal ultrasound thermotherapy. The underlying operating principle of this applicator is to rotate a plane ultrasound beam electronically. For this purpose, eight adjacent transducers were successively excited with appropriate delay times so as to generate a plane wave. The exposure direction was changed by exciting a different set of eight elements. For these feasibility studies, we used a cylindrical prototype (OD 10.6 mm) composed of 16 elementary transducers distributed over a quarter of the cylinder, all operating at 4.55 MHz. The active part was mechanically reinforced by a rigid damper structure behind the transducers. It was shown that an ultrasound field similar to that emitted by a plane transducer could be generated. Ex vivo experiments on pig's liver demonstrated that the ultrasound beam could be accurately rotated to generate sector-based lesions to a suitable depth (up to 19 mm). Throughout these experiments, exposures lasting 20 s were delivered at an acoustic intensity of 17 W cm{sup -2}. By varying the power from exposure to exposure, the depth of the lesion at different angles could be controlled.

  9. HIFU Monitoring and Control with Dual-Mode Ultrasound Arrays

    Casper, Andrew Jacob

    The biological effects of high-intensity focused ultrasound (HIFU) have been known and studied for decades. HIFU has been shown capable of treating a wide variety of diseases and disorders. However, despite its demonstrated potential, HIFU has been slow to gain clinical acceptance. This is due, in part, to the difficulty associated with robustly monitoring and controlling the delivery of the HIFU energy. The non-invasive nature of the surgery makes the assessment of treatment progression difficult, leading to long treatment times and a significant risk of under treatment. This thesis research develops new techniques and systems for robustly monitoring HIFU therapies for the safe and efficacious delivery of the intended treatment. Systems and algorithms were developed for the two most common modes of HIFU delivery systems: single-element and phased array applicators. Delivering HIFU with a single element transducer is a widely used technique in HIFU therapies. The simplicity of a single element offers many benefits in terms of cost and overall system complexity. Typical monitoring schemes rely on an external device (e.g. diagnostic ultrasound or MRI) to assess the progression of therapy. The research presented in this thesis explores using the same element to both deliver and monitor the HIFU therapy. The use of a dual-mode ultrasound transducer (DMUT) required the development of an FPGA based single-channel arbitrary waveform generator and high-speed data acquisition unit. Data collected from initial uncontrolled ablations led to the development of monitoring and control algorithms which were implemented directly on the FPGA. Close integration between the data acquisition and arbitrary waveform units allowed for fast, low latency control over the ablation process. Results are presented that demonstrate control of HIFU therapies over a broad range of intensities and in multiple in vitro tissues. The second area of investigation expands the DMUT research to an

  10. Photoacoustic-guided ultrasound therapy with a dual-mode ultrasound array

    Prost, Amaury; Funke, Arik; Tanter, Mickaël; Aubry, Jean-François; Bossy, Emmanuel

    2012-06-01

    Photoacoustics has recently been proposed as a potential method to guide and/or monitor therapy based on high-intensity focused ultrasound (HIFU). We experimentally demonstrate the creation of a HIFU lesion at the location of an optical absorber, by use of photoacoustic signals emitted by the absorber detected on a dual mode transducer array. To do so, a dedicated ultrasound array intended to both detect photoacoustic waves and emit HIFU with the same elements was used. Such a dual-mode array provides automatically coregistered reference frames for photoacoustic detection and HIFU emission, a highly desired feature for methods involving guidance or monitoring of HIFU by use of photoacoustics. The prototype is first characterized in terms of both photoacoustic and HIFU performances. The probe is then used to perform an idealized scenario of photoacoustic-guided therapy, where photoacoustic signals generated by an absorbing thread embedded in a piece of chicken breast are used to automatically refocus a HIFU beam with a time-reversal mirror and necrose the tissue at the location of the absorber.

  11. A nonlinear lumped model for ultrasound systems using CMUT arrays.

    Satir, Sarp; Degertekin, F Levent

    2015-10-01

    We present a nonlinear lumped model that predicts the electrical input-output behavior of an ultrasonic system using CMUTs with arbitrary array/membrane/electrode geometry in different transmit-receive configurations and drive signals. The receive-only operation, where the electrical output signal of the CMUT array in response to incident pressure field is calculated, is included by modifying the boundary elementbased vibroacoustic formulation for a CMUT array in rigid baffle. Along with the accurate large signal transmit model, this formulation covers pitch-catch and pulse-echo operation when transmit and receive signals can be separated in time. In cases when this separation is not valid, such as CMUTs used in continuous wave transmit-receive mode, pulse-echo mode with a nearby hard or soft wall or in a bounded space such as in a microfluidic channel, an efficient formulation based on the method of images is used. Some of these particular applications and the overall modeling approach have been validated through comparison with finite element analysis on specific examples including CMUTs with multiple electrodes. To further demonstrate the capability of the model for imaging applications, the two-way response of a partial dual-ring intravascular ultrasound array is simulated using a parallel computing cluster, where the output currents of individual array elements are calculated for given input pulse and compared with experimental results. With its versatility, the presented model can be a useful tool for rapid iterative CMUT-based system design and simulation for a broad range of ultrasonic applications. PMID:26470049

  12. 30 MHz radar observations of artificial E region field-aligned plasma irregularities

    D. L. Hysell

    2008-01-01

    Artificial E region field aligned irregularities (FAIs) have been observed during heating experiments at the HAARP facility using a new 30 MHz coherent scatter radar imager deployed near Homer, Alaska. Irregularities were observed during brief experiments on three quiet days in July and August, 2007, when the daytime E region critical frequency was close to 3 MHz. Irregularities were consistently generated and detected during experiments with O-mode HF pumping on zenith with a 1-min on, 1-min...

  13. Acoustical cross-talk in row–column addressed 2-D transducer arrays for ultrasound imaging

    Christiansen, Thomas Lehrmann; Jensen, Jørgen Arendt; Thomsen, Erik Vilain

    2015-01-01

    The acoustical cross-talk in row–column addressed 2-D transducer arrays for volumetric ultrasound imaging is investigated. Experimental results from a 2.7 MHz, λ/2-pitch capacitive micromachined ultrasonic transducer (CMUT) array with 62 rows and 62 columns are presented and analyzed in the...

  14. Diffraction and coherence in breast ultrasound tomography: a study with a toroidal array

    Huang, Lianjie [Los Alamos National Laboratory; Simonetti, Francesco [IMPERIAL COLL.; Duric, Neb [KCI; Littrup, Peter [KCI

    2008-01-01

    Ultrasound is commonly used as an adjunct to mammography for diagnostic evaluation of suspicions arising from breast cancer screening. As an alternative to conventional sonography that uses hand-held transducers, toroidal array probes that encircle the breast immersed in a water bath have been investigated for ultrasound tomography. In this paper, two sets of experiments performed with a prototype ultrasound scanner on a phantom and a human breast in vivo are used to investigate the effects of diffraction and coherence in ultrasound tomography. Reconstructions obtained with transmission diffraction tomography (TDT) are compared with conventional reflection imaging and computerized ultrasound tomography showing a substantial improvement. The in vivo tests demonstrate that TDT can image the complex boundary of a cancer mass and suggest that it can reveal the anatomy of milk ducts and Cooper's ligaments.

  15. Elastic characterization of swine aorta by scanning acoustic microscopy at 30 MHz

    Blase, Christopher; Shelke, Amit; Kundu, Tribikram; Bereiter-Hahn, Jürgen

    2011-04-01

    The mechanical properties of blood vessel walls are important determinants of physiology and pathology of the cardiovascular system. Acoustic imaging (B mode) is routinely used in a clinical setting to determine blood flow and wall distensibility. In this study scanning acoustic microscopy in vitro is used to determine spatially resolved tissue elastic properties. Broadband excitation of 30 MHz has been applied through scanning acoustic microscopy (SAM) for topographical imaging of swine thoracic aorta in reflection mode. Three differently treated tissue samples were investigated with SAM: a) treated with elastase to remove elastin, b) autoclaving for 5 hours to remove collagen and c) fresh controlled untreated sample as control. Experimental investigations are conducted for studying the contribution of individual protein components (elastin and collagen) to the material characteristics of the aortic wall. Conventional tensile testing has been conducted on the tissue samples to study the mechanical behavior. The mechanical properties measured by SAM and tensile testing show qualitative agreement.

  16. Synthetic Aperture Beamforming in Ultrasound using Moving Arrays

    Andresen, Henrik

    significant slice was missed and allows a more precise measurement of organ dimensions [2, 3, 4]. Conventional 3D ultrasound imaging is basically faced with two limitations. It is only able to have a single transmit focus point and each line in a 3D volume has to be created independently. This reduces image......Medical ultrasound (US) is widely used because it allows cheap real-time imaging of soft tissue with no known side-effects or hazards to either patients or operating personnel. US has existed since the 1960s and was originally adapted from the concept of radar and sonar. The development in...... ultrasound has allowed the technology to evolve from a showing a simple echo along a line to fully visualize entire organs. The image changes significantly depending on the orientation of the transducer, making it more difficult to see exact features. This poses challenges since anatomy is three...

  17. Improved beamforming using curved sparse 2D arrays in ultrasound.

    Kirkebø, Jan Egil; Austeng, Andreas

    2007-05-01

    In this work we have investigated the effect of curving phase-steered sparse periodic two-dimensional arrays in one direction, and relate this effect to the geometry of the arrays. We have shown that curving is equivalent to removing some of the element periodicity, thus adding some "randomness" to the layout. Compared to flat phase-steered periodically sparse two-dimensional arrays, curving offers an even greater suppression of grating lobes located at directions along the curvature. The class of arrays yielding improved performance due to this suppression of grating lobes has been characterized. The point spread functions of some previously proposed array layouts, shown to be promising for ultrasonic imaging, have been simulated. The arrays have been simulated with various number of elements as well as various focal points, with array and field parameters typical to those in volumetric cardiac imaging. On a 48 x 48 element grid with a transducer center frequency of 3 MHz and the target at 40 mm, reductions in the peak sidelobe level of up to 12dB were recorded for some critical steering directions, without significant differences in the beamwidth. The integrated sidelobe ratio was also examined, showing an almost equivalent performance as the flat array. This study shows that, without adding any complexity to the system, the overall image quality of a volumetric imaging system can be improved significantly by curving the array in one direction. PMID:17313966

  18. Electric Field Signatures in Wideband, 3 MHz and 30 MHz of Negative Ground Flashes Pertinent to Swedish Thunderstorms

    Mohd Muzafar Ismail

    2015-12-01

    Full Text Available In this study, the electric field signatures of negative ground flashes pertinent to the Swedish thunderstorms were recorded simultaneously during the summer of 2014 using wide (up to 100 MHz and narrow (at 3 MHz and 30 MHz as central frequencies bandwidth antenna systems. The electric field signatures were recorded for a time duration of 250 ms. In the analysis, the whole flash was considered and a total of 98 flashes were chosen where electric field signatures of all wideband, 3 MHz and 30 MHz signals were present. It is observed that preliminary breakdown pulses are stronger radiators at 3 and 30 MHz compared to the return strokes. A comparison of our results with those of the previous studies obtained from different geographical regions clearly shows that the strength of preliminary breakdown pulses is higher in the temperate region (Sweden for instance and is a function of latitude.

  19. Image-guided ultrasound phased arrays are a disruptive technology for non-invasive therapy.

    Hynynen, Kullervo; Jones, Ryan M

    2016-09-01

    Focused ultrasound offers a non-invasive way of depositing acoustic energy deep into the body, which can be harnessed for a broad spectrum of therapeutic purposes, including tissue ablation, the targeting of therapeutic agents, and stem cell delivery. Phased array transducers enable electronic control over the beam geometry and direction, and can be tailored to provide optimal energy deposition patterns for a given therapeutic application. Their use in combination with modern medical imaging for therapy guidance allows precise targeting, online monitoring, and post-treatment evaluation of the ultrasound-mediated bioeffects. In the past there have been some technical obstacles hindering the construction of large aperture, high-power, densely-populated phased arrays and, as a result, they have not been fully exploited for therapy delivery to date. However, recent research has made the construction of such arrays feasible, and it is expected that their continued development will both greatly improve the safety and efficacy of existing ultrasound therapies as well as enable treatments that are not currently possible with existing technology. This review will summarize the basic principles, current statures, and future potential of image-guided ultrasound phased arrays for therapy. PMID:27494561

  20. Genomic SNP array as a gold standard for prenatal diagnosis of foetal ultrasound abnormalities

    M. Srebniak (Malgorzata); M. Boter (Marjan); G.G. Oudesluijs (Grétel); T.E. Cohen-Overbeek (Titia); L.C. Govaerts (Lutgarde); K.E.M. Diderich (Karin); R. Oegema (Renske); M.F.C.M. Knapen (Maarten); I.M.B.H. van de Laar (Ingrid); M. Joosten (Marieke); A.R.M. van Opstal (Diane); R-J.H. Galjaard (Robert-Jan)

    2012-01-01

    textabstractBackground: We have investigated whether replacing conventional karyotyping by SNP array analysis in cases of foetal ultrasound abnormalities would increase the diagnostic yield and speed of prenatal diagnosis in clinical practice. Findings/results. From May 2009 till June 2011 we perfor

  1. Image-guided ultrasound phased arrays are a disruptive technology for non-invasive therapy

    Hynynen, Kullervo; Jones, Ryan M.

    2016-09-01

    Focused ultrasound offers a non-invasive way of depositing acoustic energy deep into the body, which can be harnessed for a broad spectrum of therapeutic purposes, including tissue ablation, the targeting of therapeutic agents, and stem cell delivery. Phased array transducers enable electronic control over the beam geometry and direction, and can be tailored to provide optimal energy deposition patterns for a given therapeutic application. Their use in combination with modern medical imaging for therapy guidance allows precise targeting, online monitoring, and post-treatment evaluation of the ultrasound-mediated bioeffects. In the past there have been some technical obstacles hindering the construction of large aperture, high-power, densely-populated phased arrays and, as a result, they have not been fully exploited for therapy delivery to date. However, recent research has made the construction of such arrays feasible, and it is expected that their continued development will both greatly improve the safety and efficacy of existing ultrasound therapies as well as enable treatments that are not currently possible with existing technology. This review will summarize the basic principles, current statures, and future potential of image-guided ultrasound phased arrays for therapy.

  2. 30 MHz radar observations of artificial E region field-aligned plasma irregularities

    D. L. Hysell

    2008-02-01

    Full Text Available Artificial E region field aligned irregularities (FAIs have been observed during heating experiments at the HAARP facility using a new 30 MHz coherent scatter radar imager deployed near Homer, Alaska. Irregularities were observed during brief experiments on three quiet days in July and August, 2007, when the daytime E region critical frequency was close to 3 MHz. Irregularities were consistently generated and detected during experiments with O-mode HF pumping on zenith with a 1-min on, 1-min off CW modulation. The scattering cross sections, rise, and fall times of the echoes were observed as well as their spectral properties. Results were found to be mainly in agreement with observations from other mid- and high-latitude sites with some discrepancies. Radar images of the irregularity-filled volume on one case exhibited clear variations in backscatter power and Doppler shift across the volume. The images furthermore show the emergence of a small irregularity-filled region to the south southwest of the main region in the approximate direction of magnetic zenith.

  3. 30 MHz hardware digital filter for signals of the ZEUS forward tracking detector

    Here we describe the FADC modules for the 5184 channels of the forward tracking detector of the ZEUS experiment at HERA (DESY), which convert the incoming analogue signals on a 104 MHz clock and apply a hardware digital filtering and zero suppression procedure on the acquired data. A module works on 32 input channels, nine boards are grouped in a 9HU crate. On a given trigger, the data are sequentially transferred to an output buffer for final acquisition, passing a 30 MHz digital filter and zero suppression hardware. The module uses a 9 bit signed FIR filter with eight tabs, where the eight filter coefficients are freely programmable. Only signals with two successive filtered values above a certain threshold are stored for output. Due to the filter procedure the data reduction rate is greater than 95%. The system provides a processing power of 600 mops per board for the foreseen application. In addition to the data reduction the main benefit of the filtering process is the significantly improved separation of double signals. ((orig.))

  4. SOUND-SPEED TOMOGRAPHY USING FIRST-ARRIVAL TRANSMISSION ULTRASOUND FOR A RING ARRAY

    HUANG, LIANJIE [Los Alamos National Laboratory; QUAN, YOULI [Los Alamos National Laboratory

    2007-01-31

    Sound-speed tomography images can be used for cancer detection and diagnosis. Tumors have generally higher sound speeds than the surrounding tissue. Quality and resolution of tomography images are primarily determined by the insonification/illumination aperture of ultrasound and the capability of the tomography method for accurately handling heterogeneous nature of the breast. We investigate the capability of an efficient time-of-flight tomography method using transmission ultrasound from a ring array for reconstructing sound-speed images of the breast. The method uses first arrival times of transmitted ultrasonic signals emerging from non-beamforming ultrasound transducers located around a ring. It properly accounts for ray bending within the breast by solving the eikonal equation using a finite-difference scheme. We test and validate the time-of-flight transmission tomography method using synthetic data for numerical breast phantoms containing various objects. In our simulation, the objects are immersed in water within a ring array. Two-dimensional synthetic data are generated using a finite-difference scheme to solve acoustic-wave equation in heterogeneous media. We study the reconstruction accuracy of the tomography method for objects with different sizes and shapes as well as different perturbations from the surrounding medium. In addition, we also address some specific data processing issues related to the tomography. Our tomography results demonstrate that the first-arrival transmission tomography method can accurately reconstruct objects larger than approximately five wavelengths of the incident ultrasound using a ring array.

  5. Real-time photoacoustic and ultrasound imaging: a simple solution for clinical ultrasound systems with linear arrays

    Montilla, Leonardo G.; Olafsson, Ragnar; Bauer, Daniel R.; Witte, Russell S.

    2013-01-01

    Recent clinical studies have demonstrated that photoacoustic imaging (PAI) provides important diagnostic information during a routine breast exam for cancer. PAI enhances contrast between blood vessels and background tissue, which can help characterize suspicious lesions. However, most PAI systems are either not compatible with commercial ultrasound systems or inefficiently deliver light to the region of interest, effectively reducing the sensitivity of the technique. To address and potentially overcome these limitations, we developed an accessory for a standard linear ultrasound array that optimizes light delivery for PAI. The photoacoustic enabling device (PED) exploits an optically transparent acoustic reflector to help direct laser illumination to the region of interest. This study compares the PED with standard fiber bundle illumination in scattering and non-scattering media. In scattering media with the same incident fluence, the PED enhanced the photoacoustic signal by 18 dB at a depth of 5 mm and 6 dB at a depth of 20 mm. To demonstrate in vivo feasibility, we also used the device to image a mouse with a pancreatic tumor. The PED identified blood vessels at the periphery of the tumor, suggesting that PAI provides complementary contrast to standard pulse echo ultrasound. The PED is a simple and inexpensive solution that facilitates the translation of PAI technology to the clinic for routine screening of breast cancer.

  6. Predicting the sky from 30 MHz to 800 GHz: the extended Global Sky Model

    Liu, Adrian

    We propose to construct the extended Global Sky Model (eGSM), a software package and associated data products that are capable of generating maps of the sky at any frequency within a broad range (30 MHz to 800 GHz). The eGSM is constructed from archival data, and its outputs will include not only "best estimate" sky maps, but also accurate error bars and the ability to generate random realizations of missing modes in the input data. Such views of the sky are crucial in the practice of precision cosmology, where our ability to constrain cosmological parameters and detect new phenomena (such as B-mode signatures from primordial gravitational waves, or spectral distortions of the Cosmic Microwave Background; CMB) rests crucially on our ability to remove systematic foreground contamination. Doing so requires empirical measurements of the foreground sky brightness (such as that arising from Galactic synchrotron radiation, among other sources), which are typically performed only at select narrow wavelength ranges. We aim to transcend traditional wavelength limits by optimally combining existing data to provide a comprehensive view of the foreground sky at any frequency within the broad range of 30 MHz to 800 GHz. Previous efforts to interpolate between multi-frequency maps resulted in the Global Sky Model (GSM) of de Oliveira-Costa et al. (2008), a software package that outputs foreground maps at any frequency of the user's choosing between 10 MHz and 100 GHz. However, the GSM has a number of shortcomings. First and foremost, the GSM does not include the latest archival data from the Planck satellite. Multi-frequency models depend crucially on data from Planck, WMAP, and COBE to provide high-frequency "anchor" maps. Another crucial shortcoming is the lack of error bars in the output maps. Finally, the GSM is only able to predict temperature (i.e., total intensity) maps, and not polarization information. With the recent release of Planck's polarized data products, the

  7. Solar U- and J- Bursts at the Frequencies 10-30MHz

    Dorovskyy, V. V.; Melnik, V. N.; Konovalenko, A. A.; Abranin, E. P.; Rucker, H. O.; Lecacheux, A.

    2006-08-01

    In the present report we discuss the results of observations of solar U- and J- bursts over the frequency range 10-30MHz, which have been obtained within the framework of an international observational campaign in June - August, 2004 at the radio telescope UTR-2 (Kharkov, Ukraine). We succeed to observe these types of bursts for the first time at such a low frequencies due to combination of large effective area of the radio telescope and high sensitivity of the new back-end. During June - August, 2004 about 30 U- and J- bursts were registered, and only 5 of them were confidently identified as U-bursts that may speak about the relative sparsity of the latter at mentioned frequencies. Both the isolated bursts and their sequences were observed. On average the turning frequencies lay in the range 10-22 MHz that corresponds to the arches heliocentric heights of 1.6-2.2 solar radii. In some sequences the bursts turning frequency was stable that may indicate the arch stability, while in others the turning frequency had tendency to vary from burst to burst. Durations of U- and J- bursts did not differ from those of usual Type III bursts (3-7s), while the drift rates of an ascending arm (on the average -1MHz/ s) was a little bit lower, than those of ordinary Type III bursts in this range. The harmonic structure of U- and J- bursts, and also Jb-J pairs (analogous to IIIb-III pairs) were registered. Also L-shaped bursts (Leblanc and Hoyos, 1985) were recorded. A specific feature of L-shaped bursts is prolonged zero-drift region on their dynamic spectra. The sizes and configurations of the arches were estimated on the base of obtained data. Possible explanations of the observed properties of U- and J- bursts are discussed.

  8. Design, development, and evaluation of focused ultrasound arrays for transesophageal cardiac ablations

    Lee, Hotaik

    The ultimate purpose of this dissertation is the evaluation of the feasibility of transesophageal cardiac surgery in arrhythmia treatment, using therapeutic ultrasound energy without the requirement for surgical incisions or blood contact. Atrial fibrillation (AF) is the most common cardiac arrhythmia, affecting over 2.2 million Americans. One effective treatment is cardiac ablation, which shows a high rate of success in treating paroxysmal AF. As a prevailing modality for this treatment, catheter ablation using radiofrequency has been effective, but there is measurable morbidity and significant costs and time associated with this invasive procedure for permanent or persistent AF. To address these issues, a transesophageal ultrasound applicator for noninvasive cardiac ablations has been designed, developed and evaluated in this dissertation. Focused ultrasound for thermal ablation has gained interest for decades due to its noninvasive characteristics. Since the esophagus is close to the posterior of the left atrium, its position makes it attractive for the incision-less surgery of the selected area of the heart using ultrasound. The overall goal of this study is to bring an applicator as closely as possible to the heart in order to effectively deliver ultrasound energy, and create electrically isolating lesions in myocardial tissue, replicating the currently used Maze procedure. The Maze procedure is a surgical operation that treats AF by creating a grid of incisions resulting in non-conductive scar tissue in the atria. The initial design of an ultrasound applicator capable of creating atrial lesions from the esophagus, involved evaluating sound pressure fields within layers of the esophagus and myocardium. Based on the multiple factors of the simulation results of transducer arrays, current transesophageal medical devices, and the throat anatomy, a focused ultrasound transducer that can be inserted into the esophagus has been designed and tested. In this study, a

  9. Multiple-frequency phased array patterns for therapeutic ultrasound

    Ballard, John R.; Liu, Dalong; Casper, Andrew J.; Wan, Yayun; Almekkawy, Mohamed; Ebbini, Emad S.

    2012-10-01

    Modern transducer technology allows for the design and implementation of therapeutic arrays with relatively wide bandwidths (>50%) and low cross coupling between elements. We present results from a 3.5 MHz, 64-element prototype designed for small-animal and superficial therapeutic HIFU applications (Imasonic, Inc.) This transducer has a 58% 6-dB fractional BW average on its elements allowing for therapeutic output in the frequency range of 2.7 - 4.6 MHz. We present a simulation/experimental study to evaluate and optimize the focusing capabilities of the phased array prototype when excited by multiple-frequency components. Preliminary results have shown that multiple-frequency excitation may be beneficial in enhancing the therapeutic effects of HIFU beams. A multiple-focus pattern synthesis algorithm for arrays excited by multiple-frequency signals has been developed and tested using linear pressure field simulations. The algorithm maintains the precise phase relationship between the frequency components at each focal spot to achieve a desirable outcome. Hydrophone measurements to validate the approach show that nonlinear effects at the focal location are more prominent with the frequency mixing compared to conventional single frequency excitation. An in vitro study of lesion formation in freshly excised porcine liver was investigated.

  10. High-Frequency Ultrasound Array Designed for Ultrasound-Guided Breast Biopsy.

    Cummins, Thomas; Eliahoo, Payam; Kirk Shung, K

    2016-06-01

    This paper describes the development of a miniaturized high-frequency linear array that can be integrated within a core biopsy needle to improve tissue sampling accuracy during breast cancer biopsy procedures. The 64-element linear array has an element width of [Formula: see text], kerf width of [Formula: see text], element length of 1 mm, and element thickness of [Formula: see text]. The 2-2 array composite was fabricated using deep reactive ion etching of lead magnesium niobate-lead titanate (PMN-PT) single crystal material. The array composite fabrication process as well as a novel high-density electrical interconnect solution are presented and discussed. Array performance measurements show that the array had a center frequency and fractional bandwidth ([Formula: see text]) of 59.1 MHz and 29.4%, respectively. Insertion loss and adjacent element crosstalk at the center frequency were -41.0 and [Formula: see text], respectively. A B-mode image of a tungsten wire target phantom was captured using a synthetic aperture imaging system and the imaging test results demonstrate axial and lateral resolutions of 33.2 and [Formula: see text], respectively. PMID:27046895

  11. In vivo visualization of robotically implemented synthetic tracked aperture ultrasound (STRATUS) imaging system using curvilinear array

    Zhang, Haichong K.; Aalamifar, Fereshteh; Boctor, Emad M.

    2016-04-01

    Synthetic aperture for ultrasound is a technique utilizing a wide aperture in both transmit and receive to enhance the ultrasound image quality. The limitation of synthetic aperture is the maximum available aperture size limit determined by the physical size of ultrasound probe. We propose Synthetic-Tracked Aperture Ultrasound (STRATUS) imaging system to overcome the limitation by extending the beamforming aperture size through ultrasound probe tracking. With a setup involving a robotic arm, the ultrasound probe is moved using the robotic arm, while the positions on a scanning trajectory are tracked in real-time. Data from each pose are synthesized to construct a high resolution image. In previous studies, we have demonstrated the feasibility through phantom experiments. However, various additional factors such as real-time data collection or motion artifacts should be taken into account when the in vivo target becomes the subject. In this work, we build a robot-based STRATUS imaging system with continuous data collection capability considering the practical implementation. A curvilinear array is used instead of a linear array to benefit from its wider capture angle. We scanned human forearms under two scenarios: one submerged the arm in the water tank under 10 cm depth, and the other directly scanned the arm from the surface. The image contrast improved 5.51 dB, and 9.96 dB for the underwater scan and the direct scan, respectively. The result indicates the practical feasibility of STRATUS imaging system, and the technique can be potentially applied to the wide range of human body.

  12. A 1372-element Large Scale Hemispherical Ultrasound Phased Array Transducer for Noninvasive Transcranial Therapy

    Noninvasive transcranial therapy using high intensity focused ultrasound transducers has attracted high interest as a promising new modality for the treatments of brain related diseases. We describe the development of a 1372 element large scale hemispherical ultrasound phased array transducer operating at a resonant frequency of 306 kHz. The hemispherical array has a diameter of 31 cm and a 15.5 cm radius of curvature. It is constructed with piezoelectric (PZT-4) tube elements of a 10 mm in diameter, 6 mm in length and 1.4 mm wall thickness. Each element is quasi-air backed by attaching a cork-rubber membrane on the back of the element. The acoustic efficiency of the element is determined to be approximately 50%. The large number of the elements delivers high power ultrasound and offers better beam steering and focusing capability. Comparisons of sound pressure-squared field measurements with theoretical calculations in water show that the array provides good beam steering and tight focusing capability over an efficient volume of approximately 100x100x80 mm3 with nominal focal spot size of approximately 2.3 mm in diameter at -6 dB. We also present its beam steering and focusing capability through an ex vivo human skull by measuring pressure-squared amplitude after phase corrections. These measurements show the same efficient volume range and focal spot sizes at -6 dB as the ones in water without the skull present. These results indicate that the array is sufficient for use in noninvasive transcranial ultrasound therapy.

  13. A 1372-element Large Scale Hemispherical Ultrasound Phased Array Transducer for Noninvasive Transcranial Therapy

    Song, Junho; Hynynen, Kullervo

    2009-04-01

    Noninvasive transcranial therapy using high intensity focused ultrasound transducers has attracted high interest as a promising new modality for the treatments of brain related diseases. We describe the development of a 1372 element large scale hemispherical ultrasound phased array transducer operating at a resonant frequency of 306 kHz. The hemispherical array has a diameter of 31 cm and a 15.5 cm radius of curvature. It is constructed with piezoelectric (PZT-4) tube elements of a 10 mm in diameter, 6 mm in length and 1.4 mm wall thickness. Each element is quasi-air backed by attaching a cork-rubber membrane on the back of the element. The acoustic efficiency of the element is determined to be approximately 50%. The large number of the elements delivers high power ultrasound and offers better beam steering and focusing capability. Comparisons of sound pressure-squared field measurements with theoretical calculations in water show that the array provides good beam steering and tight focusing capability over an efficient volume of approximately 100×100×80 mm3 with nominal focal spot size of approximately 2.3 mm in diameter at -6 dB. We also present its beam steering and focusing capability through an ex vivo human skull by measuring pressure-squared amplitude after phase corrections. These measurements show the same efficient volume range and focal spot sizes at -6 dB as the ones in water without the skull present. These results indicate that the array is sufficient for use in noninvasive transcranial ultrasound therapy.

  14. Genomic SNP array as a gold standard for prenatal diagnosis of foetal ultrasound abnormalities

    Srebniak Malgorzata I

    2012-03-01

    Full Text Available Abstract Background We have investigated whether replacing conventional karyotyping by SNP array analysis in cases of foetal ultrasound abnormalities would increase the diagnostic yield and speed of prenatal diagnosis in clinical practice. Findings/results From May 2009 till June 2011 we performed HumanCytoSNP-12 array (HCS (http://www.Illumina.com analysis in 207 cases of foetal structural abnormalities. HCS allows detecting unbalanced genomic abnormalities with a resolution of about 150/200 kb. All cases were selected by a clinical geneticist after excluding the most common aneuploidies by RAD (rapid aneuploidy detection. Pre-test genetic counselling was offered in all cases. In 24/207 (11,6% foetuses a clinically relevant genetic abnormality was detected. Only 8/24 abnormalities would have been detected if only routine karyotyping was performed. Submicroscopic abnormalities were found in 16/207 (7,7% cases. The array results were achieved within 1-2 weeks after amniocentesis. Conclusions Prenatal SNP array testing is faster than karyotyping and allows detecting much smaller aberrations (~0.15 Mb in addition to the microscopic unbalanced chromosome abnormalities detectable with karyotyping (~ > 5 Mb. Since karyotyping would have missed 66% (16/24 of genomic abnormalities in our cohort, we propose to perform genomic high resolution array testing assisted by pre-test counselling as a primary prenatal diagnostic test in cases of foetal ultrasound abnormalities.

  15. Validity and reliability of rectus femoris ultrasound measurements: Comparison of curved-array and linear-array transducers

    Kendra Hammond, MD

    2014-11-01

    Full Text Available Muscle-mass loss augers increased morbidity and mortality in critically ill patients. Muscle-mass loss can be assessed by wide linear-array ultrasound transducers connected to cumbersome, expensive console units. Whether cheaper, hand-carried units equipped with curved-array transducers can be used as alternatives is unknown. Accordingly, our primary aim was to investigate in 15 nondisabled subjects the validity of measurements of rectus femoris cross-sectional area by using a curved-array transducer against a linear-array transducer—the reference-standard technique. In these subjects, we also determined the reliability of measurements obtained by a novice operator versus measurements obtained by an experienced operator. Lastly, the relationship between quadriceps strength and rectus area recorded by two experienced operators with a curved-array transducer was assessed in 17 patients with chronic obstructive pulmonary disease (COPD. In nondisabled subjects, the rectus cross-sectional area measured with the curved-array transducer by the novice and experienced operators was valid (intraclass correlation coefficient [ICC]: 0.98, typical percentage error [%TE]: 3.7% and reliable (ICC: 0.79, %TE: 9.7%. In the subjects with COPD, both reliability (ICC: 0.99 and repeatability (%TE: 7.6% and 9.8% were high. Rectus area was related to quadriceps strength in COPD for both experienced operators (coefficient of determination: 0.67 and 0.70. In conclusion, measurements of rectus femoris cross-sectional area recorded with a curved-array transducer connected to a hand-carried unit are valid, reliable, and reproducible, leading us to contend that this technique is suitable for cross-sectional and longitudinal studies.

  16. Piezoelectric Micromachined Ultrasound Transducer (PMUT Arrays for Integrated Sensing, Actuation and Imaging

    Yongqiang Qiu

    2015-04-01

    Full Text Available Many applications of ultrasound for sensing, actuation and imaging require miniaturized and low power transducers and transducer arrays integrated with electronic systems. Piezoelectric micromachined ultrasound transducers (PMUTs, diaphragm-like thin film flexural transducers typically formed on silicon substrates, are a potential solution for integrated transducer arrays. This paper presents an overview of the current development status of PMUTs and a discussion of their suitability for miniaturized and integrated devices. The thin film piezoelectric materials required to functionalize these devices are discussed, followed by the microfabrication techniques used to create PMUT elements and the constraints the fabrication imposes on device design. Approaches for electrical interconnection and integration with on-chip electronics are discussed. Electrical and acoustic measurements from fabricated PMUT arrays with up to 320 diaphragm elements are presented. The PMUTs are shown to be broadband devices with an operating frequency which is tunable by tailoring the lateral dimensions of the flexural membrane or the thicknesses of the constituent layers. Finally, the outlook for future development of PMUT technology and the potential applications made feasible by integrated PMUT devices are discussed.

  17. MR thermometry characterization of a hyperthermia ultrasound array designed using the k-space computational method

    Lee Hotaik

    2006-10-01

    Full Text Available Abstract Background Ultrasound induced hyperthermia is a useful adjuvant to radiation therapy in the treatment of prostate cancer. A uniform thermal dose (43°C for 30 minutes is required within the targeted cancerous volume for effective therapy. This requires specific ultrasound phased array design and appropriate thermometry method. Inhomogeneous, acoustical, three-dimensional (3D prostate models and economical computational methods provide necessary tools to predict the appropriate shape of hyperthermia phased arrays for better focusing. This research utilizes the k-space computational method and a 3D human prostate model to design an intracavitary ultrasound probe for hyperthermia treatment of prostate cancer. Evaluation of the probe includes ex vivo and in vivo controlled hyperthermia experiments using the noninvasive magnetic resonance imaging (MRI thermometry. Methods A 3D acoustical prostate model was created using photographic data from the Visible Human Project®. The k-space computational method was used on this coarse grid and inhomogeneous tissue model to simulate the steady state pressure wavefield of the designed phased array using the linear acoustic wave equation. To ensure the uniformity and spread of the pressure in the length of the array, and the focusing capability in the width of the array, the equally-sized elements of the 4 × 20 elements phased array were 1 × 14 mm. A probe was constructed according to the design in simulation using lead zerconate titanate (PZT-8 ceramic and a Delrin® plastic housing. Noninvasive MRI thermometry and a switching feedback controller were used to accomplish ex vivo and in vivo hyperthermia evaluations of the probe. Results Both exposimetry and k-space simulation results demonstrated acceptable agreement within 9%. With a desired temperature plateau of 43.0°C, ex vivo and in vivo controlled hyperthermia experiments showed that the MRI temperature at the steady state was 42.9 ± 0.38

  18. Comparison of 3-D Synthetic Aperture Phased-Array Ultrasound Imaging and Parallel Beamforming

    Rasmussen, Morten Fischer; Jensen, Jørgen Arendt

    2014-01-01

    This paper demonstrates that synthetic apertureimaging (SAI) can be used to achieve real-time 3-D ultra-sound phased-array imaging. It investigates whether SAI in-creases the image quality compared with the parallel beam-forming (PB) technique for real-time 3-D imaging. Data areobtained using both...... simulations and measurements with anultrasound research scanner and a commercially available 3.5-MHz 1024-element 2-D transducer array. To limit the probecable thickness, 256 active elements are used in transmit andreceive for both techniques. The two imaging techniques weredesigned for cardiac imaging, which...... requires sequences de-signed for imaging down to 15cm of depth and a frame rateof at least 20Hz. The imaging quality of the two techniquesis investigated through simulations as a function of depth andangle. SAI improved the full-width at half-maximum (FWHM) at low steering angles by 35%, and the 20-d...

  19. Sample volume misregistration in linear array-based dual beam Doppler ultrasound systems.

    Steel, Robin; Fish, Peter J

    2003-07-01

    Large velocity estimation errors can occur in dual beam Doppler ultrasound velocity measurement systems when there is left/right sample volume misregistration, particularly when the interbeam angle is small. Such misregistration will occur when there is tissue inhomogeneity. This is investigated for a typical type of inhomogeneity--a layer of fat--by calculating the amount of both angle and translation misregistration occurring in such a system realized using a single linear array transducer. The complex sample volume sensitivity is calculated using a modified time domain approach, combining the spatial impulse response method with ray tracing. The effects on these misregistrations of altering the aperture sizes and their relative positions on the array is then investigated to derive an improved aperture configuration for dual beam velocity estimation. Arrangements with transmit apertures wider than the receive apertures are shown to be preferable in this context. PMID:12894917

  20. The design of a focused ultrasound transducer array for the treatment of stroke: a simulation study

    Pajek, Daniel; Hynynen, Kullervo

    2012-08-01

    High intensity focused ultrasound (HIFU) is capable of mechanically disintegrating blood clots at high pressures. Safe thrombolysis may require frequencies higher than those currently utilized by transcranial HIFU. Since the attenuation and focal distortion of ultrasound in bone increases at higher frequencies, resulting focal pressures are diminished. This study investigated the feasibility of using transcranial HIFU for the non-invasive treatment of ischemic stroke. The use of large aperture, 1.1-1.5 MHz phased arrays in targeting four clinically relevant vessel locations was simulated. Resulting focal sizes decreased with frequency, producing a maximum -3 dB depth of field and lateral width of 2.0 and 1.2 mm, respectively. Mean focal gains above an order of magnitude were observed in three of four targets and transducer intensities required to achieve thrombolysis were determined. Required transducer element counts are about an order of magnitude higher than what currently exists and so, although technically feasible, new arrays would need to be developed to realize this as a treatment modality for stroke.

  1. The design of a focused ultrasound transducer array for the treatment of stroke: a simulation study

    High intensity focused ultrasound (HIFU) is capable of mechanically disintegrating blood clots at high pressures. Safe thrombolysis may require frequencies higher than those currently utilized by transcranial HIFU. Since the attenuation and focal distortion of ultrasound in bone increases at higher frequencies, resulting focal pressures are diminished. This study investigated the feasibility of using transcranial HIFU for the non-invasive treatment of ischemic stroke. The use of large aperture, 1.1–1.5 MHz phased arrays in targeting four clinically relevant vessel locations was simulated. Resulting focal sizes decreased with frequency, producing a maximum –3 dB depth of field and lateral width of 2.0 and 1.2 mm, respectively. Mean focal gains above an order of magnitude were observed in three of four targets and transducer intensities required to achieve thrombolysis were determined. Required transducer element counts are about an order of magnitude higher than what currently exists and so, although technically feasible, new arrays would need to be developed to realize this as a treatment modality for stroke. (paper)

  2. A random phased array device for delivery of high intensity focused ultrasound

    Hand, J W [Radiological Sciences Unit, Imperial College Healthcare NHS Trust, Hammersmith Hospital, London W12 0HS (United Kingdom); Shaw, A; Sadhoo, N; Rajagopal, S [Acoustics Group, National Physical Laboratory, Teddington TW11 0LW (United Kingdom); Dickinson, R J [Department of Bioengineering, Imperial College London, London SW7 2AZ (United Kingdom); Gavrilov, L R [N.N. Andreev Acoustics Institute, 117036 Moscow (Russian Federation)], E-mail: j.hand@imperial.ac.uk

    2009-10-07

    Randomized phased arrays can offer electronic steering of a single focus and simultaneous multiple foci concomitant with low levels of secondary maxima and are potentially useful as sources of high intensity focused ultrasound (HIFU). This work describes laboratory testing of a 1 MHz random phased array consisting of 254 elements on a spherical shell of radius of curvature 130 mm and diameter 170 mm. Acoustic output power and efficiency are measured for a range of input electrical powers, and field distributions for various single- and multiple-focus conditions are evaluated by a novel technique using an infrared camera to provide rapid imaging of temperature changes on the surface of an absorbing target. Experimental results show that the array can steer a single focus laterally to at least {+-}15 mm off axis and axially to more than {+-}15 mm from the centre of curvature of the array and patterns of four and five simultaneous foci {+-}10 mm laterally and axially whilst maintaining low intensity levels in secondary maxima away from the targeted area in good agreement with linear theoretical predictions. Experiments in which pork meat was thermally ablated indicate that contiguous lesions several cm{sup 3} in volume can be produced using the patterns of multiple foci.

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

    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.

  4. 3-D Ultrasound Imaging Performance of a Row-Column Addressed 2-D Array Transducer: A Measurement Study

    Rasmussen, Morten Fischer; Jensen, Jørgen Arendt

    A real-time 3-D ultrasound measurement using only 32 elements and 32 emissions is presented. The imaging quality is compared to a conventionally fully addressed array using 1024 elements and 256 emissions. The main-lobe of the measured line spread function is almost identical, but the side...

  5. SUPER-RESOLUTION ULTRASOUND TOMOGRAPHY: A PRELIMINARY STUDY WITH A RING ARRAY

    HUANG, LIANJIE [Los Alamos National Laboratory; SIMONETTI, FRANCESCO [NON LANL; DURIC, NEBOJSA [NON LANL; RAMA, OLSI [NON LANL

    2007-01-18

    Ultrasound tomography attempts to retrieve the structure of an objective by exploiting the interaction of acoustic waves with the object. A fundamental limit of ultrasound tomography is that features cannot be resolved if they are spaced less than {lambda}/2 apart, where {lambda} is wavelength of the probing wave, regardless of the degree of accuracy of the measurements. Therefore, since the attenuation of the probing wave with propagation distance increases as {lambda} decreases, resolution has to be traded against imaging depth. Recently, it has been shown that the {lambda}/2 limit is a consequence of the Born approximation (implicit in the imaging algorithms currently employed) which neglects the distortion of the probing wavefield as it travels through the medium to be imaged. On the other hand, such a distortion, which is due to the multiple scattering phenomenon, can encode unlimited resolution in the radiating component of the scattered field. Previously, a resolution better than {lambda}/3 has been reported in these proceedings [F. Simonetti, pp. 126 (2006)] in the case of elastic wave probing. In this paper, they demonstrate experimentally a resolution better than {lambda}/4 for objects immersed in a water bth probed by means of a ring array which excites and detects pressure waves in a full view configuration.

  6. In vivo imaging of inducible tyrosinase gene expression with an ultrasound array-based photoacoustic system

    Harrison, Tyler; Paproski, Robert J.; Zemp, Roger J.

    2012-02-01

    Tyrosinase, a key enzyme in the production of melanin, has shown promise as a reporter of genetic activity. While green fluorescent protein has been used extensively in this capacity, it is limited in its ability to provide information deep in tissue at a reasonable resolution. As melanin is a strong absorber of light, it is possible to image gene expression using tyrosinase with photoacoustic imaging technologies, resulting in excellent resolutions at multiple-centimeter depths. While our previous work has focused on creating and imaging MCF-7 cells with doxycycline-controlled tyrosinase expression, we have now established the viability of these cells in a murine model. Using an array-based photoacoustic imaging system with 5 MHz center frequency, we capture interleaved ultrasound and photoacoustic images of tyrosinase-expressing MCF-7 tumors both in a tissue mimicking phantom, and in vivo. Images of both the tyrosinase-expressing tumor and a control tumor are presented as both coregistered ultrasound-photoacoustic B-scan images and 3-dimensional photoacoustic volumes created by mechanically scanning the transducer. We find that the tyrosinase-expressing tumor is visible with a signal level 12dB greater than that of the control tumor in vivo. Phantom studies with excised tumors show that the tyrosinase-expressing tumor is visible at depths in excess of 2cm, and have suggested that our imaging system is sensitive to a transfection rate of less than 1%.

  7. Ultrasound nondestructive evaluation (NDE) imaging with transducer arrays and adaptive processing.

    Li, Minghui; Hayward, Gordon

    2012-01-01

    This paper addresses the challenging problem of ultrasonic non-destructive evaluation (NDE) imaging with adaptive transducer arrays. In NDE applications, most materials like concrete, stainless steel and carbon-reinforced composites used extensively in industries and civil engineering exhibit heterogeneous internal structure. When inspected using ultrasound, the signals from defects are significantly corrupted by the echoes form randomly distributed scatterers, even defects that are much larger than these random reflectors are difficult to detect with the conventional delay-and-sum operation. We propose to apply adaptive beamforming to the received data samples to reduce the interference and clutter noise. Beamforming is to manipulate the array beam pattern by appropriately weighting the per-element delayed data samples prior to summing them. The adaptive weights are computed from the statistical analysis of the data samples. This delay-weight-and-sum process can be explained as applying a lateral spatial filter to the signals across the probe aperture. Simulations show that the clutter noise is reduced by more than 30 dB and the lateral resolution is enhanced simultaneously when adaptive beamforming is applied. In experiments inspecting a steel block with side-drilled holes, good quantitative agreement with simulation results is demonstrated. PMID:22368457

  8. Simultaneous positioning of cells into two-dimensional arrays using ultrasound.

    Neild, Adrian; Oberti, Stefano; Radziwill, Gerald; Dual, Jürg

    2007-08-01

    Contactless simultaneous positioning of micrometer-sized particles in suspension (e.g., copolymer beads, living cells, silicon microparts) can be performed using ultrasound. Current devices are capable of collecting particles into planes or lines by exciting a resonance in the fluid by means of a piezoelectric transducer located beneath the fluidic cavity and are designed such that a one-dimensional pressure field is created. The focus of this work is to collect cells in distinct point locations for potential drug screening array applications. A device to create two-dimensional arrays of cells within a micromachined chamber is described. The chamber is etched into a silicon wafer and sealed with glass; on the underside of the silicon layer a piezoelectric actuator is attached. A signal is applied to each of two orthogonally aligned strips electrodes defined on the surface of the piezoelectric plate. These two strip electrodes create independently addressable approximately one-dimensional pressure fields. It is shown that by applying the same signal to each electrode a diagonally aligned grid of cells can be produced. However, the independence of the two electrodes allows the application of two signals with slightly different frequencies to be applied which creates a grid of circular cell clumps highly suitable for the identified application. (c) PMID:17187440

  9. Thermoacoustic range verification using a clinical ultrasound array provides perfectly co-registered overlay of the Bragg peak onto an ultrasound image

    Patch, S. K.; Kireeff Covo, M.; Jackson, A.; Qadadha, Y. M.; Campbell, K. S.; Albright, R. A.; Bloemhard, P.; Donoghue, A. P.; Siero, C. R.; Gimpel, T. L.; Small, S. M.; Ninemire, B. F.; Johnson, M. B.; Phair, L.

    2016-08-01

    The potential of particle therapy due to focused dose deposition in the Bragg peak has not yet been fully realized due to inaccuracies in range verification. The purpose of this work was to correlate the Bragg peak location with target structure, by overlaying the location of the Bragg peak onto a standard ultrasound image. Pulsed delivery of 50 MeV protons was accomplished by a fast chopper installed between the ion source and the cyclotron inflector. The chopper limited the train of bunches so that 2 Gy were delivered in 2 μ \\text{s} . The ion pulse generated thermoacoustic pulses that were detected by a cardiac ultrasound array, which also produced a grayscale ultrasound image. A filtered backprojection algorithm focused the received signal to the Bragg peak location with perfect co-registration to the ultrasound images. Data was collected in a room temperature water bath and gelatin phantom with a cavity designed to mimic the intestine, in which gas pockets can displace the Bragg peak. Phantom experiments performed with the cavity both empty and filled with olive oil confirmed that displacement of the Bragg peak due to anatomical change could be detected. Thermoacoustic range measurements in the waterbath agreed with Monte Carlo simulation within 1.2 mm. In the phantom, thermoacoustic range estimates and first-order range estimates from CT images agreed to within 1.5 mm.

  10. Thermoacoustic range verification using a clinical ultrasound array provides perfectly co-registered overlay of the Bragg peak onto an ultrasound image.

    Patch, S K; Kireeff Covo, M; Jackson, A; Qadadha, Y M; Campbell, K S; Albright, R A; Bloemhard, P; Donoghue, A P; Siero, C R; Gimpel, T L; Small, S M; Ninemire, B F; Johnson, M B; Phair, L

    2016-08-01

    The potential of particle therapy due to focused dose deposition in the Bragg peak has not yet been fully realized due to inaccuracies in range verification. The purpose of this work was to correlate the Bragg peak location with target structure, by overlaying the location of the Bragg peak onto a standard ultrasound image. Pulsed delivery of 50 MeV protons was accomplished by a fast chopper installed between the ion source and the cyclotron inflector. The chopper limited the train of bunches so that 2 Gy were delivered in [Formula: see text]. The ion pulse generated thermoacoustic pulses that were detected by a cardiac ultrasound array, which also produced a grayscale ultrasound image. A filtered backprojection algorithm focused the received signal to the Bragg peak location with perfect co-registration to the ultrasound images. Data was collected in a room temperature water bath and gelatin phantom with a cavity designed to mimic the intestine, in which gas pockets can displace the Bragg peak. Phantom experiments performed with the cavity both empty and filled with olive oil confirmed that displacement of the Bragg peak due to anatomical change could be detected. Thermoacoustic range measurements in the waterbath agreed with Monte Carlo simulation within 1.2 mm. In the phantom, thermoacoustic range estimates and first-order range estimates from CT images agreed to within 1.5 mm. PMID:27385261

  11. The role of acoustic nonlinearity in tissue heating behind the rib cage using high intensity focused ultrasound phased array

    Yuldashev, Petr V.; Shmeleva, Svetlana M.; Ilyin, Sergey A.; Sapozhnikov, Oleg A.; Gavrilov, Leonid R.; Khokhlova, Vera A.

    2013-01-01

    The goal of this study was to investigate theoretically the effects of nonlinear propagation in a high intensity focused ultrasound (HIFU) field produced by a therapeutic phased array and the resultant heating of tissue behind a rib cage. Three configurations of focusing were simulated: in water, in water with ribs in the beam path, and in water with ribs backed by a layer of soft tissue. The Westervelt equation was used to model the nonlinear HIFU field and a 1 MHz phased array consisting of...

  12. The correlation of the 10 to 30 MeV proton flux from the NOAA satellites and the Thule 30 MHz riometer. Technical memo

    There is a requirement for realtime specification of riometer absorption in the polar cap region using proton flux measured with satellite-borne detectors. The proton flux data from the NOAA series of satellites and the Thule 30 MHz riometer data satisfy this requirement. A study was done to correlate these two parameters within state-of-the-art theoretical reasoning

  13. A preliminary evaluation work on a 3D ultrasound imaging system for 2D array transducer

    Zhong, Xiaoli; Li, Xu; Yang, Jiali; Li, Chunyu; Song, Junjie; Ding, Mingyue; Yuchi, Ming

    2016-04-01

    This paper presents a preliminary evaluation work on a pre-designed 3-D ultrasound imaging system. The system mainly consists of four parts, a 7.5MHz, 24×24 2-D array transducer, the transmit/receive circuit, power supply, data acquisition and real-time imaging module. The row-column addressing scheme is adopted for the transducer fabrication, which greatly reduces the number of active channels . The element area of the transducer is 4.6mm by 4.6mm. Four kinds of tests were carried out to evaluate the imaging performance, including the penetration depth range, axial and lateral resolution, positioning accuracy and 3-D imaging frame rate. Several strong reflection metal objects , fixed in a water tank, were selected for the purpose of imaging due to a low signal-to-noise ratio of the transducer. The distance between the transducer and the tested objects , the thickness of aluminum, and the seam width of the aluminum sheet were measured by a calibrated micrometer to evaluate the penetration depth, the axial and lateral resolution, respectively. The experiment al results showed that the imaging penetration depth range was from 1.0cm to 6.2cm, the axial and lateral resolution were 0.32mm and 1.37mm respectively, the imaging speed was up to 27 frames per second and the positioning accuracy was 9.2%.

  14. A 63 element 1.75 dimensional ultrasound phased array for the treatment of benign prostatic hyperplasia

    Smith Nadine

    2005-06-01

    Full Text Available Abstract Background Prostate cancer and benign prostatic hyperplasia are very common diseases in older American men, thus having a reliable treatment modality for both diseases is of great importance. The currently used treating options, mainly surgical ones, have numerous complications, which include the many side effects that accompany such procedures, besides the invasive nature of such techniques. Focused ultrasound is a relatively new treating modality that is showing promising results in treating prostate cancer and benign prostatic hyperplasia. Thus this technique is gaining more attention in the past decade as a non-invasive method to treat both diseases. Methods In this paper, the design, construction and evaluation of a 1.75 dimensional ultrasound phased array to be used for treating prostate cancer and benign prostatic hyperplasia is presented. With this array, the position of the focus can be controlled by changing the electrical power and phase to the individual elements for electronically focusing and steering in a three dimensional volume. The array was designed with a maximum steering angle of ± 13.5° in the transverse direction and a maximum depth of penetration of 11 cm, which allows the treatment of large prostates. The transducer piezoelectric ceramic, matching layers and cable impedance have been designed for maximum power transfer to tissue. Results To verify the capability of the transducer for focusing and steering, exposimetry was performed and the results correlated well with the calculated field. Ex vivo experiments using bovine tissue were performed with various lesion sizes and indicated the capability of the transducer to ablate tissue using short sonications. Conclusion A 1.75 dimensional array, that overcame the drawbacks associated with one-dimensional arrays, has been designed, built and successfully tested. Design issues, such as cable and ceramic capacitances, were taken into account when designing this

  15. Targeted hyperthermia in prostate with an MR-guided endorectal ultrasound phased array: patient specific modeling and preliminary experiments

    Salgaonkar, Vasant A.; Prakash, Punit; Plata, Juan; Holbrook, Andrew; Rieke, Viola; Kurhanewicz, John; Hsu, I.-C.; Diederich, Chris J.

    2013-02-01

    Feasibility of hyperthermia delivery to the prostate with a commercially available MR-guided endorectal ultrasound (ERUS) phased array ablation system (ExAblate 2100, Insightec, LTD) was assessed through computer simulations and ex vivo experiments. The simulations included a 3D FEM-based biothermal model, and acoustic field calculations for the ExAblate phased array (2.3 MHz, 2.3x4.0 cm2) using the rectangular radiator method. Array beamforming strategies were investigated to deliver 30-min hyperthermia (prostate cancer, identified from MR images in representative patient cases. Constraints on power densities, sonication durations and switching speeds imposed by ExAblate hardware and software were incorporated in the models. THIFU systems can be controlled for continuous hyperthermia in prostate to augment radiotherapy and drug delivery. [FUS Foundation, NIH R01 122276, 111981].

  16. A Flexible Ultrasound Transducer Array with Micro-Machined Bulk PZT

    Zhe Wang

    2015-01-01

    Full Text Available This paper proposes a novel flexible piezoelectric micro-machined ultrasound transducer, which is based on PZT and a polyimide substrate. The transducer is made on the polyimide substrate and packaged with medical polydimethylsiloxane. Instead of etching the PZT ceramic, this paper proposes a method of putting diced PZT blocks into holes on the polyimide which are pre-etched. The device works in d31 mode and the electromechanical coupling factor is 22.25%. Its flexibility, good conformal contacting with skin surfaces and proper resonant frequency make the device suitable for heart imaging. The flexible packaging ultrasound transducer also has a good waterproof performance after hundreds of ultrasonic electric tests in water. It is a promising ultrasound transducer and will be an effective supplementary ultrasound imaging method in the practical applications.

  17. Quantitative shear-wave optical coherence elastography with a programmable phased array ultrasound as the wave source.

    Song, Shaozhen; Le, Nhan Minh; Huang, Zhihong; Shen, Tueng; Wang, Ruikang K

    2015-11-01

    The purpose of this study is to implement a beam-steering ultrasound as the wave source for shear-wave optical coherence elastography (SW-OCE) to achieve an extended range of elastic imaging of the tissue sample. We introduce a linear phased array ultrasound transducer (LPAUT) as the remote and programmable wave source and a phase-sensitive optical coherence tomography (OCT) as the sensitive shear-wave detector. The LPAUT is programmed to launch acoustic radiation force impulses (ARFI) focused at desired locations within the range of OCT imaging, upon which the elasticity map of the entire OCT B-scan cross section is recovered by spatial compounding of the elastic maps derived from each launch of AFRIs. We also propose a directional filter to separate the shear-wave propagation at different directions in order to reduce the effect of tissue heterogeneity on the shear-wave propagation within tissue. The feasibility of this proposed approach is then demonstrated by determining the stiffness of tissue-mimicking phantoms with agarose concentrations of 0.5% and 1% and also by imaging the Young's modulus of retinal and choroidal tissues within a porcine eye ball ex vivo. The approach opens up opportunities to combine medical ultrasound imaging and SW-OCE for high-resolution localized quantitative assessment of tissue biomechanical property. PMID:26512505

  18. A cylindrical-section ultrasound phased-array applicator for hyperthermia cancer therapy.

    Ebbini, E S; Umemura, S I; Ibbini, M; Cain, C A

    1988-01-01

    A phased-array applicator geometry for deep localized hyperthermia is presented. The array consists of rectangular transducer elements forming a section of a cylinder that conforms to the body portals in the abdominal and pelvic regions. Focusing and scanning properties of the cylindrical-section array are investigated in homogeneous lossy media using appropriate computer simulations. The characteristic focus of this array is shown to be spatially limited in both transverse and longitudinal directions with intensity gain values suitable for deep hyperthermia applications. The ability of the cylindrical-section phased array to generate multiple foci using the field conjugation method is examined. The effect of the grating lobes on the power deposition pattern of the scanned field is shown to be minimal. Steady-state temperature distributions are simulated using a three-dimensional thermal model of the normal tissue layers surrounding a tumor of typical volume. The advantages and the limitations of this array configuration are discussed. PMID:18290188

  19. Focusing of high intensity ultrasound through the rib cage using a therapeutic random phased array

    Bobkova, Svetlana; Gavrilov, Leonid; Khokhlova, Vera; Shaw, Adam; Hand, Jeffrey; ,

    2010-01-01

    A method for focusing high intensity ultrasound through a rib cage that aims to minimize heating of the ribs whilst maintaining high intensities at the focus (or foci) is proposed and tested theoretically and experimentally. Two approaches, one based on geometric acoustics and the other accounting for diffraction effects associated with propagation through the rib cage, are investigated theoretically for idealized source conditions. It is shown that for an idealized radiator the diffraction a...

  20. Development of Endoscopic Ultrasound Radial Arrays%环形内窥镜超声换能器的研制

    陈燕; 周丹; 林国豪; 吴锦川; 戴吉岩; 罗豪甦; 陈王丽华

    2014-01-01

    本论文报道了当前环形内窥镜超声换能器的两种不同的制备方法以及其性能的表征。方法一为先采用切割薄片高性能压电PMN-PT单晶和其1~3复合材料制备平面阵列,然后将平面阵列卷曲成圆环形阵列。所制备的128阵元PMN-PT单晶阵列具有较宽带宽达78%,64阵元PMN-PT单晶/环氧1~3复合阵列带宽高达102%。方法二为旋转切割法,通过直接对带有匹配层和背衬材料的压电陶瓷管进行切割,制作不同尺寸及频率的环形超声内窥镜阵列。%We report the fabrication and characterization of endoscopic ultrasound radial arrays transducers for medical imaging by two different methods. The ifrst approach is cal ed wrapping method, high-performance PMN-PT single crystal and PMN-PT/epoxy 1-3 composite plates are used as active elements. After bonded with backing and matching layers and being cut into arrays, transducers are wrapped across a metal tube to form the radial arrays. The bandwidth of the 128-element PMN-PT single crystal radial array and 64-element PMN-PT/epoxy 1-3 composite radial array transducers can achieved 78%and 102%, respectively. In the second method, the PZT tube was selected to fabricate the 50-element 14 MHz and 100-element 3 MHz radial arrays by a rotate-and-dice method. The results show that these two methods are feasible to fabricate radial arrays for endoscopic applications.

  1. Volumetric Ultrasound Imaging with Row-Column Addressed 2-D Arrays Using Spatial Matched Filter Beamforming

    Bouzari, Hamed; Engholm, Mathias; Christiansen, Thomas Lehrmann;

    2015-01-01

    . However, the achievable spatial resolution and contrast of the B-mode images in Delay and Sum (DAS) beamforming are limited by the aperture size and by the operating frequency. This paper, investigates Spatial Matched Filter (SMF) beamforming on row-column addressed 2-D arrays to increase spatial...

  2. Ultrasound pulse-echo measurements on rough surfaces with linear array transducers

    Sjøj, Sidsel M. N.; Blanco, Esther N.; Wilhjelm, Jens E.;

    2012-01-01

    The echo from planar surfaces with rms roughness, Rq, in the range from 0-155 μm was measured with a clinical linear array transducer at different angles of incidence at 6 MHz and 12 MHz. The echo-pulse from the surfaces was isolated with an equal sized window and the power of the echo-pulse was ...

  3. Inspection of copper canisters for spent nuclear fuel by means of ultrasound. Phased arrays, ultrasonic imaging and nonlinear acoustics

    This report contains the research results concerning advanced ultrasound for the inspection of copper canisters for spent nuclear fuel obtained at Signals and Systems, Uppsala University in years 2003/2004. After a short introduction a review of beam forming fundamentals required for proper understanding phased array operation is included. The factors that determine lateral resolution during ultrasonic imaging of flaws in solids are analyzed and results of simulations modelling contact inspection of copper are presented. In the second chapter an improved synthetic aperture imaging (SAI) technique is introduced. The proposed SAI technique is characterized by an enhanced lateral resolution compared with the previously proposed extended synthetic aperture focusing technique (ESAFT). The enhancement of imaging performance is achieved due to more realistic assumption concerning the probability density function of scatterers in the region of interest. The proposed technique takes the form of a two-step algorithm using the result obtained in the first step as a prior for the second step. Final chapter contains summary of our recent experimental and theoretical research on nonlinear ultrasonics of unbounded interfaces. A new theoretical model for rough interfaces is developed, and the experimental results from the copper specimens that mimic contact cracks of different types are presented. Derivation of the theory and selected measurement results are given in appendix

  4. Inspection of copper canisters for spent nuclear fuel by means of ultrasound. Phased arrays, ultrasonic imaging and nonlinear acoustics

    Stepinski, Tadeusz (ed.); Ping Wu; Wennerstroem, Erik [Uppsala Univ. (Sweden). Signals and Systems

    2004-09-01

    This report contains the research results concerning advanced ultrasound for the inspection of copper canisters for spent nuclear fuel obtained at Signals and Systems, Uppsala University in years 2003/2004. After a short introduction a review of beam forming fundamentals required for proper understanding phased array operation is included. The factors that determine lateral resolution during ultrasonic imaging of flaws in solids are analyzed and results of simulations modelling contact inspection of copper are presented. In the second chapter an improved synthetic aperture imaging (SAI) technique is introduced. The proposed SAI technique is characterized by an enhanced lateral resolution compared with the previously proposed extended synthetic aperture focusing technique (ESAFT). The enhancement of imaging performance is achieved due to more realistic assumption concerning the probability density function of scatterers in the region of interest. The proposed technique takes the form of a two-step algorithm using the result obtained in the first step as a prior for the second step. Final chapter contains summary of our recent experimental and theoretical research on nonlinear ultrasonics of unbounded interfaces. A new theoretical model for rough interfaces is developed, and the experimental results from the copper specimens that mimic contact cracks of different types are presented. Derivation of the theory and selected measurement results are given in appendix.

  5. Pre-clinical testing of a phased array ultrasound system for MRI-guided noninvasive surgery of the brain-A primate study

    MRI-guided and monitored focused ultrasound thermal surgery of brain through intact skull was tested in three rhesus monkeys. The aim of this study was to determine the amount of skull heating in an animal model with a head shape similar to that of a human. The ultrasound beam was generated by a 512 channel phased array system (Exablate[reg] 3000, InSightec, Haifa, Israel) that was integrated within a 1.5-T MR-scanner. The skin was pre-cooled by degassed temperature controlled water circulating between the array surface and the skin. Skull surface temperature was measured with invasive thermocouple probes. The results showed that by applying surface cooling the skin and skull surface can be protected, and that the brain surface temperature becomes the limiting factor. The MRI thermometry was shown to be useful in detecting the tissue temperature distribution next to the bone, and it should be used to monitor the brain surface temperature. The acoustic intensity values during the 20 s sonications were adequate for thermal ablation in the human brain provided that surface cooling is used

  6. Pre-clinical testing of a phased array ultrasound system for MRI-guided noninvasive surgery of the brain-A primate study

    Hynynen, Kullervo [Department of Radiology, Brigham and Women' s Hospital and Harvard Medical School, 75 Francis Street, Boston, MA 02115 (United States)]. E-mail: kullervo@bwh.harvard.edu; McDannold, Nathan [Department of Radiology, Brigham and Women' s Hospital and Harvard Medical School, 75 Francis Street, Boston, MA 02115 (United States); Clement, Greg [Department of Radiology, Brigham and Women' s Hospital and Harvard Medical School, 75 Francis Street, Boston, MA 02115 (United States); Jolesz, Ferenc A. [Department of Radiology, Brigham and Women' s Hospital and Harvard Medical School, 75 Francis Street, Boston, MA 02115 (United States); Zadicario, Eyal [InSightec, Inc., Haifa (Israel); Killiany, Ron [Boston University, Boston, MA (United States); Moore, Tara [Boston University, Boston, MA (United States); Rosen, Douglas [Boston University, Boston, MA (United States)

    2006-08-15

    MRI-guided and monitored focused ultrasound thermal surgery of brain through intact skull was tested in three rhesus monkeys. The aim of this study was to determine the amount of skull heating in an animal model with a head shape similar to that of a human. The ultrasound beam was generated by a 512 channel phased array system (Exablate[reg] 3000, InSightec, Haifa, Israel) that was integrated within a 1.5-T MR-scanner. The skin was pre-cooled by degassed temperature controlled water circulating between the array surface and the skin. Skull surface temperature was measured with invasive thermocouple probes. The results showed that by applying surface cooling the skin and skull surface can be protected, and that the brain surface temperature becomes the limiting factor. The MRI thermometry was shown to be useful in detecting the tissue temperature distribution next to the bone, and it should be used to monitor the brain surface temperature. The acoustic intensity values during the 20 s sonications were adequate for thermal ablation in the human brain provided that surface cooling is used.

  7. 3D ultrasound imaging performance of a row-column addressed 2D array transducer: a simulation study

    Rasmussen, Morten Fischer; Jensen, Jørgen Arendt

    2013-01-01

    This paper compares the imaging performance of a 128+128 element row-column addressed array with a fully addressed 1616 2D array. The comparison is made via simulations of the point spread function with Field II. Both arrays have lambda-pitch, a center frequency of 3:5MHz and use 256 active...

  8. Advanced 3-D Ultrasound Imaging.:3-D Synthetic Aperture Imaging and Row-column Addressing of 2-D Transducer Arrays

    Rasmussen, Morten Fischer; Jensen, Jørgen Arendt

    2014-01-01

    The main purpose of the PhD project was to develop methods that increase the 3-D ultrasound imaging quality available for the medical personnel in the clinic. Acquiring a 3-D volume gives the medical doctor the freedom to investigate the measured anatomy in any slice desirable after the scan has been completed. This allows for precise measurements of organs dimensions and makes the scan more operator independent. Real-time 3-D ultrasound imaging is still not as widespread in use in the clinic...

  9. General Ultrasound Imaging

    Full Text Available ... kidneys. There are three types of Doppler ultrasound: Color Doppler uses a computer to convert Doppler measurements into an array of colors to show the speed and direction of blood ...

  10. General Ultrasound Imaging

    Full Text Available ... 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 ...

  11. Ultrasound -- Pelvis

    Full Text Available ... News Physician Resources Professions Site Index A-Z Ultrasound - Pelvis Ultrasound imaging of the pelvis uses sound ... limitations of Pelvic Ultrasound Imaging? What is Pelvic Ultrasound Imaging? Ultrasound is safe and painless, and produces ...

  12. Ultrasound -- Pelvis

    Full Text Available ... of Pelvic Ultrasound Imaging? What is Pelvic Ultrasound Imaging? Ultrasound is safe and painless, and produces pictures ... page What are the limitations of Pelvic Ultrasound Imaging? Ultrasound waves are disrupted by air or gas; ...

  13. Lateral mode coupling to reduce the electrical impedance of small elements required for high power ultrasound therapy phased arrays

    Hynynen, Kullervo; Yin, Jianhua

    2009-01-01

    A method that uses lateral coupling to reduce the electrical impedance of small transducer elements in generating ultrasound waves was tested. Cylindrical, radially-polled transducer elements were driven at their length resonance frequency. Computer simulation and experimental studies showed that the electrical impedance of the transducer element could be controlled by the cylinder wall thickness, while the operation frequency was determined by the cylinder length. Acoustic intensity (average...

  14. Annular and Cylindrical Phased Array Geometries for Transrectal High-Intensity Focused Ultrasound (HIFU) using PZT and Piezocomposite Materials

    Seip, Ralf; Chen, Wohsing; Carlson, Roy; Frizzell, Leon; Warren, Gary; Smith, Nadine; Saleh, Khaldon; Gerber, Gene; Shung, Kirk; Guo, Hongkai; Sanghvi, Narendra T.

    2005-03-01

    This paper presents engineering progress and the latest in-vitro and in-vivo results obtained with a 4.0 MHz, 20 element, PZT annular transrectal HIFU array and several 4.0 MHz, 211 element, PZT and piezocomposite cylindrical transrectal HIFU arrays for the treatment of prostate cancer. The geometries of both arrays were designed and analyzed to steer the HIFU beams to the desired sites in the prostate volume using multi-channel electronic drivers, with the intent to increase treatment efficiency and reliability for the next generation of HIFU systems. The annular array is able to focus in depth from 25 mm to 50 mm, generate total acoustic powers in excess of 60W, and has been integrated into a modified Sonablate®500 HIFU system capable of controlling such an applicator through custom treatment planning and execution software. Both PZT- and piezocomposite cylindrical arrays were constructed and their characteristics were compared for the transrectal applications. These arrays have been installed into appropriate transducer housings, and have undergone characterization tests to determine their total acoustic power output, focusing range (in depth and laterally), focus quality, efficiency, and comparison tests to determine the material and technology of choice (PZT or piezocomposite) for intra-cavity HIFU applications. Array descriptions, characterization results, in-vitro and in-vivo results, and an overview of their intended use through the application software is shown.

  15. The role of acoustic nonlinearity in tissue heating behind a rib cage using a high-intensity focused ultrasound phased array

    Yuldashev, Petr V.; Shmeleva, Svetlana M.; Ilyin, Sergey A.; Sapozhnikov, Oleg A.; Gavrilov, Leonid R.; Khokhlova, Vera A.

    2013-04-01

    The goal of this study was to investigate theoretically the effects of nonlinear propagation in a high-intensity focused ultrasound (HIFU) field produced by a therapeutic phased array and the resultant heating of tissue behind a rib cage. Three configurations of focusing were simulated: in water, in water with ribs in the beam path and in water with ribs backed by a layer of soft tissue. The Westervelt equation was used to model the nonlinear HIFU field, and a 1 MHz phased array consisting of 254 circular elements was used as a boundary condition to the model. The temperature rise in tissue was modelled using the bioheat equation, and thermally necrosed volumes were calculated using the thermal dose formulation. The shapes of lesions predicted by the modelling were compared with those previously obtained in in vitro experiments at low-power sonications. Intensity levels at the face of the array elements that corresponded to the formation of high-amplitude shock fronts in the focal region were determined as 10 W cm-2 in the free field in water and 40 W cm-2 in the presence of ribs. It was shown that exposures with shocks provided a substantial increase in tissue heating, and its better spatial localization in the main focal region only. The relative effects of overheating ribs and splitting of the focus due to the periodic structure of the ribs were therefore reduced. These results suggest that utilizing nonlinear propagation and shock formation effects can be beneficial for inducing confined HIFU lesions when irradiating through obstructions such as ribs. Design of compact therapeutic arrays to provide maximum power outputs with lower intensity levels at the elements is necessary to achieve shock wave regimes for clinically relevant sonication depths in tissue.

  16. Advantage of annular focus generation by sector-vortex array in cavitation-enhanced high-intensity focused ultrasound treatment

    Jimbo, Hayato; Takagi, Ryo; Taguchi, Kei; Yoshizawa, Shin; Umemura, Shin-ichiro

    2016-07-01

    High-intensity focused ultrasound (HIFU) is a noninvasive method for cancer treatment. One of the disadvantages of this method is that it has a long total treatment time because of the smallness of the treatment volume by a single exposure. To solve this problem, we have proposed a method of cavitation-enhanced heating, which utilized the heat generated by oscillating the cavitation bubbles, in combination with the method of lateral enlargement of a HIFU focal zone to minimize the surface volume ratio. In a previous study, focal spot scanning at multiple points was employed for the enlargement. This method involves nonlinear propagation and absorption due to the high spatial-peak temporal-peak (SPTP) intensity in addition to the cavitation-enhanced heating. However, it is difficult to predict the size and position of the coagulation volume because they are significantly affected by the nonlinear parameters of the tissue. In this study, a sector vortex method was employed to directly synthesize an annular focal pattern. Since this method can keep the SPTP intensity at a manageably low level, nonlinear propagation and absorption can be minimized. Experimental results demonstrate that the coagulation was generated only in the region where both the cavitation cloud and the heating ultrasound were matched. The proposed method will make the cavitation-enhanced HIFU treatment more accurate and predictable.

  17. Ultrasound -- Pelvis

    Full Text Available ... those sound waves to create an image. Ultrasound examinations do not use ionizing radiation (as used in ... exam may be part of a pelvic ultrasound examination. Doppler ultrasound is a special ultrasound technique that ...

  18. Obstetrical Ultrasound

    ... News Physician Resources Professions Site Index A-Z Obstetric Ultrasound Obstetric ultrasound uses sound waves to produce pictures of ... What are the limitations of Obstetrical Ultrasound Imaging? Obstetric ultrasound cannot identify all fetal abnormalities. Consequently, when ...

  19. Ultrasound -- Pelvis

    Full Text Available ... CT scanning , and MRI are the methods of choice in such a setting. Large patients are more ... content. Related Articles and Media Sonohysterography Ultrasound - Abdomen Children's (Pediatric) Ultrasound - Abdomen Obstetric Ultrasound Ultrasound - Prostate Images ...

  20. Ultrasound-assisted synthesis and visible-light-driven photocatalytic activity of Fe-incorporated TiO2 nanotube array photocatalysts

    Highlights: ► Fe–TiO2NTs were prepared by an ultrasound-assisted impregnating-calcination method. ► The absorption of TiO2NTs in visible light region was enhanced by incorporating Fe. ► Fe–TiO2NTs exhibited the enhanced visible light photocatalytic activity. ► Fe–TiO2NTs photocatalyst is promising for visible light degradation of wastewater. - Abstract: Fe incorporated TiO2 nanotube arrays (Fe–TiO2NTs) were prepared by an ultrasound-assisted impregnating-calcination method. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV–vis diffuse reflectance spectroscopy (DRS) indicated that α-Fe2O3 nanoparticles were deposited into the TiO2 nanotubes, and in the mean time, some Fe3+ ions were doped into TiO2 lattice. The absorption of Fe–TiO2NTs in the visible light region increased with the increase of Fe content. The photocatalytic activity of Fe–TiO2NTs was evaluated by the degradation of methylene blue aqueous solution under visible light irradiation. The results demonstrated that the Fe–TiO2NTs exhibited significantly enhanced photocatalytic activity compared with pure TiO2NTs. Photoluminescence (PL) and electrochemical impedance spectroscopy (EIS) analyses further confirmed that the increased photocatalytic activity of the Fe–TiO2NTs was attributed to an enhanced separation and transfer of photogenerated charge carriers.

  1. Reliability considerations of NDT by probability of detection (POD). Determination using ultrasound phased array. Results from a project in frame of the German nuclear safety research program

    Reliable assessment procedures are an important aspect of maintenance concepts. Non-destructive testing (NDT) methods are an essential part of a variety of maintenance plans. Fracture mechanical assessments require knowledge of flaw dimensions, loads and material parameters. NDT methods are able to acquire information on all of these areas. However, it has to be considered that the level of detail information depends on the case investigated and therefore on the applicable methods. Reliability aspects of NDT methods are of importance if quantitative information is required. Different design concepts e.g. the damage tolerance approach in aerospace already include reliability criteria of NDT methods applied in maintenance plans. NDT is also an essential part during construction and maintenance of nuclear power plants. In Germany, type and extent of inspection are specified in Safety Standards of the Nuclear Safety Standards Commission (KTA). Only certified inspections are allowed in the nuclear industry. The qualification of NDT is carried out in form of performance demonstrations of the inspection teams and the equipment, witnessed by an authorized inspector. The results of these tests are mainly statements regarding the detection capabilities of certain artificial flaws. In other countries, e.g. the U.S., additional blind tests on test blocks with hidden and unknown flaws may be required, in which a certain percentage of these flaws has to be detected. The knowledge of the probability of detection (POD) curves of specific flaws in specific testing conditions is often not present. This paper shows the results of a research project designed for POD determination of ultrasound phased array inspections of real and artificial cracks. The continuative objective of this project was to generate quantitative POD results. The distribution of the crack sizes of the specimens and the inspection planning is discussed, and results of the ultrasound inspections are presented. In

  2. Circumferential lesion formation around the pulmonary veins in the left atrium with focused ultrasound using a 2D-array endoesophageal device: a numerical study

    Pichardo, Samuel; Hynynen, Kullervo [Imaging Research-Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Room C713, Toronto, ON M4N 3M5 (Canada)

    2007-08-21

    Atrial fibrillation (AF) is the most frequently sustained cardiac arrhythmia affecting humans. The electrical isolation by ablation of the pulmonary veins (PVs) in the left atrium (LA) of the heart has been proven as an effective cure of AF. The ablation consists mainly in the formation of a localized circumferential thermal coagulation of the cardiac tissue surrounding the PVs. In the present numerical study, the feasibility of producing the required circumferential lesion with an endoesophageal ultrasound probe is investigated. The probe operates at 1 MHz and consists of a 2D array with enough elements (114 x 20) to steer the acoustic field electronically in a volume comparable to the LA. Realistic anatomical conditions of the thorax were considered from the segmentation of histological images of the thorax. The cardiac muscle and the blood-filled cavities in the heart were identified and considered in the sound propagation and thermal models. The influence of different conditions of the thermal sinking in the LA chamber was also studied. The circumferential ablation of the PVs was achieved by the sum of individual lesions induced with the proposed device. Different scenarios of lesion formation were considered where ultrasound exposures (1, 2, 5 and 10 s) were combined with maximal peak temperatures (60, 70 and 80 {sup 0}C). The results of this numerical study allowed identifying the limits and best conditions for controlled lesion formation in the LA using the proposed device. A controlled situation for the lesion formation surrounding the PVs was obtained when the targets were located within a distance from the device in the range of 26 {+-} 7 mm. When combined with a maximal temperature of 70 {sup 0}C and an exposure time between 5 and 10 s, this distance ensured preservation of the esophageal structures, controlled lesion formation and delivery of an acoustic intensity at the transducer surface that is compatible with existing materials. With a peak

  3. Intravascular Ultrasound

    ... Nuclear Ventriculography Optical Coherence Tomography Positron Emission Tomography (PET) Stress Echocardiography Transesophageal Echocardiography Intravascular Ultrasound | Share Intravascular ultrasound ( ...

  4. Three dimensional (3d) transverse oscillation vector velocity ultrasound imaging

    2013-01-01

    An ultrasound imaging system (300) includes a transducer array (302) with a two- dimensional array of transducer elements configured to transmit an ultrasound signal and receive echoes, transmit circuitry (304) configured to control the transducer array to transmit the ultrasound signal so as to...... the same received set of two dimensional echoes form part of the imaging system...

  5. Micromachined silicon parallel acoustic delay lines as time-delayed ultrasound detector array for real-time photoacoustic tomography

    Cho, Y.; Chang, C.-C.; Wang, L. V.; Zou, J.

    2016-02-01

    This paper reports the development of a new 16-channel parallel acoustic delay line (PADL) array for real-time photoacoustic tomography (PAT). The PADLs were directly fabricated from single-crystalline silicon substrates using deep reactive ion etching. Compared with other acoustic delay lines (e.g., optical fibers), the micromachined silicon PADLs offer higher acoustic transmission efficiency, smaller form factor, easier assembly, and mass production capability. To demonstrate its real-time photoacoustic imaging capability, the silicon PADL array was interfaced with one single-element ultrasonic transducer followed by one channel of data acquisition electronics to receive 16 channels of photoacoustic signals simultaneously. A PAT image of an optically-absorbing target embedded in an optically-scattering phantom was reconstructed, which matched well with the actual size of the imaged target. Because the silicon PADL array allows a signal-to-channel reduction ratio of 16:1, it could significantly simplify the design and construction of ultrasonic receivers for real-time PAT.

  6. Py3DFreeHandUS: A PURE PYTHON LIBRARY FOR 3D VOXEL-ARRAY RECONSTRUCTION BY USING 3D FREEHAND ULTRASOUND

    Monari, Davide; Cenni, Francesco; Aertbeliën, Erwin; Desloovere, Kaat

    2014-01-01

    INTRODUCTION and AIM 3D Freehand ultrasound (3DUS) is a technique that combines ultrasound images and position + orientation sensors (POS) with the aim to reconstruct large 3D anatomical parts. However, the few existing applications for applying this technique have at least one of the following disadvantages: i) not open-source; ii) only supporting data streams from a limited number of ultrasound or POS devices; iii) they are written in low-level languages such as C++, making rapid develop...

  7. Ultrasound -- Pelvis

    Full Text Available ... ultrasound is most often performed to evaluate the: uterus cervix ovaries fallopian tubes bladder Pelvic ultrasound exams ... to view the endometrium , the lining of the uterus, and the ovaries. Transvaginal ultrasound also provides a ...

  8. Ultrasound -- Pelvis

    Full Text Available ... make secure contact with the body and eliminate air pockets between the transducer and the skin that ... Pelvic Ultrasound Imaging? Ultrasound waves are disrupted by air or gas; therefore ultrasound is not an ideal ...

  9. Ultrasound -- Pelvis

    Full Text Available ... Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. There are ... Ultrasound page for more information . Ultrasound examinations can help diagnose symptoms experienced by women such as: pelvic ...

  10. Ultrasound -- Pelvis

    Full Text Available ... Pelvis Ultrasound imaging of the pelvis uses sound waves to produce pictures of the structures and organs ... of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or sonography , ...

  11. Ultrasound -- Pelvis

    Full Text Available ... through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. There are three types of pelvic ultrasound: ...

  12. Assessment of coronary vasomotion by intracoronary ultrasound

    Dupouy, Patrick J.; Dubois-Rande, Jean Luc; Pelle, Gabriel; Gallot, Dominique; Geschwind, Herbert J.

    1993-06-01

    Recently, new intravascular ultrasound devices for intracoronary use became available. The aim of the study was to evaluate the accuracy of intravascular ultrasound for the assessment of coronary artery vasomotion and endothelial function in patients with atherosclerosis. Twenty patients with luminal irregularities on coronary angiogram and a high cholesterol level (287 +/- 19 mg/dl) (group 1) and 6 patients with angiographically smooth arteries and a minimally elevated cholesterol level (197 +/- 12 mg/dl) (group 2) were studied. A mechanical intravascular ultrasound probe (4.3 French, 30 MHz, Cardiovascular Imaging Systems) was placed into the proximal segment of the coronary artery. Off-line measurements of the lumen area and calculation of mean intimal thickness indice was performed using digitized ultrasound images. Endothelial function was studied during a sympathetic stimulation by a cold pressor test and after intracoronary administration of papaverine and linsidomine. Mean intimal thickness was higher in group 1 than in group 2 (1.52 +/- 0.64 mm vs. 0.18 +/- 0.08 mm, p < 0.001). Linsidomine infusion induced a significant vasodilating effect in both groups (p < 0.001).

  13. Ultrasound transmission attenuation tomography using energy-scaled amplitude ratios

    Chen, Ting; Shin, Junseob; Huang, Lianjie

    2016-04-01

    Ultrasound attenuation of breast tumors is related to their types and pathological states, and can be used to detect and characterize breast cancer. Particularly, ultrasound scattering attenuation can infer the margin properties of breast tumors. Ultrasound attenuation tomography quantitatively reconstructs the attenuation properties of the breast. Our synthetic-aperture breast ultrasound tomography system with two parallel transducer arrays records both ultrasound reflection and transmission signals. We develop an ultrasound attenuation tomography method using ultrasound energy-scaled amplitude decays of ultrasound transmission signals and conduct ultrasound attenuation tomography using a known sound-speed model. We apply our ultrasound transmission attenuation tomography method to a breast phantom dataset, and compare the ultrasound attenuation tomography results with conventional beamforming ultrasound images obtained using reflection signals. We show that ultrasound transmission attenuation tomography complements beamforming images in identifying breast lesions.

  14. A multivariate study of the performance of an ultrasound-assisted madder dyes extraction and characterization by liquid chromatography-photodiode array detection

    Cuoco, Guillaume; Mathe, Carole; Archier, Paul; Chemat, Farid; Vieillescazes, Cathy

    2008-01-01

    An extraction method of madder (Rubia tinctorum) roots dyes is established and optimized to obtain the original chemical composition. A central composite design (CCD) was developed to specify the importance of the three major factors studied (time, temperature and solvent composition) affecting the ultrasound-assisted extraction of this matrix. A preliminary granulometric study of madder roots is realized in the aim to determine the optimal particles size corresponding to the best ultrasound ...

  15. Simulation study of the effects of near- and far-field heating during focused ultrasound uterine fibroid ablation using an electronically focused phased array: A theoretical analysis of patient safety

    Ellens, Nicholas, E-mail: nicholas.ellens@utoronto.ca; Hynynen, Kullervo [Sunnybrook Research Institute, Toronto, Ontario M4N 3M5, Canada and Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7 (Canada)

    2014-07-15

    Purpose: Assess the feasibility of using large-aperture, flat ultrasonic transducer arrays with 6500 small elements operating at 500 kHz without the use of any mechanical components for the thermal coagulation of uterine fibroids. This study examines the benefits and detriments of using a frequency that is significantly lower than that used in clinical systems (1–1.5 MHz). Methods: Ultrasound simulations were performed using the anatomies of five fibroid patients derived from 3D MRI. Using electronic steering solely, the ultrasound focus from a flat, 6500-element phased array was translated around the volume of the fibroids in various patterns to assess the feasibility of completing full treatments from fixed physical locations. Successive temperature maps were generated by numerically solving the bioheat equation. Using a thermal dose model, the bioeffects of these simulations were quantified and analyzed. Results: The simulations indicate that such an array could be used to perform fibroid treatments to 18 EM{sub 43} at an average rate of 90 ± 20 cm{sup 3}/h without physically moving the transducer array. On average, the maximum near-field thermal dose for each patient was below 4 EM{sub 43}. Fibroid tissue could be treated as close as 40 mm to the spine without reaching temperatures expected to cause pain or damage. Conclusions: Fibroids were successfully targeted and treated from a single transducer position to acceptable extents and without causing damage in the near- or far-field. Compared to clinical systems, treatment rates were good. The proposed treatment paradigm is a promising alternative to existing systems and warrants further investigation.

  16. Simulation study of the effects of near- and far-field heating during focused ultrasound uterine fibroid ablation using an electronically focused phased array: A theoretical analysis of patient safety

    Purpose: Assess the feasibility of using large-aperture, flat ultrasonic transducer arrays with 6500 small elements operating at 500 kHz without the use of any mechanical components for the thermal coagulation of uterine fibroids. This study examines the benefits and detriments of using a frequency that is significantly lower than that used in clinical systems (1–1.5 MHz). Methods: Ultrasound simulations were performed using the anatomies of five fibroid patients derived from 3D MRI. Using electronic steering solely, the ultrasound focus from a flat, 6500-element phased array was translated around the volume of the fibroids in various patterns to assess the feasibility of completing full treatments from fixed physical locations. Successive temperature maps were generated by numerically solving the bioheat equation. Using a thermal dose model, the bioeffects of these simulations were quantified and analyzed. Results: The simulations indicate that such an array could be used to perform fibroid treatments to 18 EM43 at an average rate of 90 ± 20 cm3/h without physically moving the transducer array. On average, the maximum near-field thermal dose for each patient was below 4 EM43. Fibroid tissue could be treated as close as 40 mm to the spine without reaching temperatures expected to cause pain or damage. Conclusions: Fibroids were successfully targeted and treated from a single transducer position to acceptable extents and without causing damage in the near- or far-field. Compared to clinical systems, treatment rates were good. The proposed treatment paradigm is a promising alternative to existing systems and warrants further investigation

  17. Ultrasound -- Pelvis

    Full Text Available ... patient. Because ultrasound images are captured in real-time, they can show the structure and movement of ... help to distract the child and make the time pass quickly. The ultrasound exam room may have ...

  18. Ultrasound -- Pelvis

    Full Text Available ... kidneys. top of page What are some common uses of the procedure? In women, a pelvic ultrasound ... patients with abnormal uterine bleeding Some physicians also use 3-D ultrasound or sonohysterography for patients with ...

  19. Ultrasound -- Pelvis

    Full Text Available ... bladder seminal vesicles prostate Transrectal ultrasound, a special study usually done to view the prostate gland, involves ... time to the procedure. If a Doppler ultrasound study is performed, you may actually hear pulse-like ...

  20. Ultrasound -- Pelvis

    Full Text Available ... internal organs, as well as blood flowing through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. There are three types of pelvic ultrasound: abdominal ( transabdominal ) vaginal ( transvaginal , endovaginal ) ...

  1. Ultrasound -- Pelvis

    Full Text Available ... Ultrasound - Prostate Images related to Ultrasound - Pelvis About this Site RadiologyInfo.org is produced by: Please note ... you can search the ACR-accredited facilities database . This website does not provide cost information. The costs ...

  2. Ultrasound -- Pelvis

    Full Text Available ... in the lower abdomen and pelvis. There are three types of pelvic ultrasound: abdominal, vaginal (for women), ... physicians diagnose and treat medical conditions. There are three types of pelvic ultrasound: abdominal ( transabdominal ) vaginal ( transvaginal , ...

  3. Ultrasound -- Pelvis

    Full Text Available ... medicine, ultrasound is used to detect changes in appearance, size or contour of organs, tissues, and vessels or to detect abnormal masses, such as tumors. In an ultrasound examination, a transducer both sends ...

  4. Ultrasound -- Pelvis

    Full Text Available ... is used to evaluate the: bladder seminal vesicles prostate Transrectal ultrasound, a special study usually done to view the prostate gland, involves inserting a specialized ultrasound transducer into ...

  5. Ultrasound -- Pelvis

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos News Physician Resources Professions Site Index A-Z Ultrasound - Pelvis Ultrasound imaging ...

  6. Ultrasound -- Pelvis

    Full Text Available ... investigation of the uterine cavity . Three-dimensional (3-D) ultrasound permits evaluation of the uterus and ovaries ... abnormal uterine bleeding Some physicians also use 3-D ultrasound or sonohysterography for patients with infertility. Three- ...

  7. Ultrasound -- Pelvis

    Full Text Available ... insertion. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... ultrasound , there are no known harmful effects on humans. top of page What are the limitations of ...

  8. Ultrasound -- Pelvis

    Full Text Available ... vaginal (for women), and rectal (for men). These exams are frequently used to evaluate the reproductive and ... women rectal ( transrectal ) for men A Doppler ultrasound exam may be part of a pelvic ultrasound examination. ...

  9. Ultrasound -- Pelvis

    Full Text Available ... needles are used to extract a sample of cells from organs for laboratory testing. Doppler ultrasound images ... ultrasound, measures the direction and speed of blood cells as they move through vessels. The movement of ...

  10. Obstetric Ultrasound

    1988-01-01

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

  11. Ultrasound -- Pelvis

    Full Text Available ... ultrasound exams are also used to monitor the health and development of an embryo or fetus during pregnancy. See the Obstetrical Ultrasound page for more information . Ultrasound examinations can help diagnose symptoms experienced by women such as: pelvic ...

  12. Cranial Ultrasound/Head Ultrasound

    ... is the procedure performed? Head Ultrasound A head ultrasound is performed in the neonatal intensive care unit (NICU) at the infant's bedside. The infant is positioned lying face-up. A clear, water-based gel is applied ...

  13. Ultrasound-modulated optical microscopy for ex-vivo imaging of scattering biological tissue

    Kothapalli, Sri-Rajasekhar; Wang, Lihong V.

    2009-02-01

    Ultrasound-modulated optical microscopy (UOM) based on a long-cavity confocal Fabry-Perot interferometer (CFPI) [J.Biomed.Opt. 13(5), 0504046, (2008)] is used for real time detection of multiply scattered light modulated by high frequency (30 MHz) ultrasound pulses propagating in an optically strongly scattering medium. In this article, we use this microscope to study the dependence of ultrasound-modulated optical signals on the optical absorption of objects embedded about 3 mm deep in tissue mimicking phantoms. These results demonstrate that the dependence is nearly linear. Most importantly, we imaged blood vasculature and melanin in highly scattering tissue samples from a mouse and a rat. Thus UOM can be used to study the morphology of blood vasculature and blood-associated functional parameters, such as oxygen saturation.

  14. Ultrasound -- Pelvis

    Full Text Available ... medical test that helps physicians diagnose and treat medical conditions. There are three types of pelvic ultrasound: abdominal ( transabdominal ) vaginal ( transvaginal , endovaginal ) ...

  15. General Ultrasound Imaging

    Full Text Available ... Physician Resources Professions Site Index A-Z General Ultrasound Ultrasound imaging uses sound waves to produce pictures ... limitations of General Ultrasound Imaging? What is General Ultrasound Imaging? Ultrasound is safe and painless, and produces ...

  16. Ultrasound -- Pelvis

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos News Physician Resources Professions Site Index A-Z Ultrasound - Pelvis Ultrasound imaging of the pelvis uses sound waves to produce pictures of ...

  17. Ultrasound -- Vascular

    ... page How is the procedure performed? For most ultrasound exams, you will be positioned lying face-up on an examination table that can be ... either side or on occasion placed in a face down position to improve the quality ... (ultrasound technologist) or radiologist then places the transducer on ...

  18. Musculoskeletal Ultrasound

    ... examination table or a swivel chair. For other ultrasound exams, the patient is positioned lying face-up or face-down on an examination table. The radiologist or sonographer may ask you to move the extremity being examined or may ... ultrasound studies of infants and children are performed with ...

  19. Ultrasound imaging using coded signals

    Misaridis, Athanasios

    Modulated (or coded) excitation signals can potentially improve the quality and increase the frame rate in medical ultrasound scanners. The aim of this dissertation is to investigate systematically the applicability of modulated signals in medical ultrasound imaging and to suggest appropriate...... excitation signal. Although a gain in signal-to-noise ratio of about 20 dB is theoretically possible for the time-bandwidth product available in ultrasound, it is shown that the effects of transducer weighting and tissue attenuation reduce the maximum gain at 10 dB for robust compression with low sidelobes...... described. Application of coded excitation in array imaging is evaluated through simulations in Field II. The low degree of the orthogonality among coded signals for ultrasound systems is first discussed, and the effect of mismatched filtering in the cross-correlation properties of the signals is evaluated...

  20. Ultrasound -- Pelvis

    Full Text Available ... ovarian cysts and uterine fibroids ovarian or uterine cancers A transvaginal ultrasound is usually performed to view ... detect: uterine anomalies uterine scars endometrial polyps fibroids cancer, especially in patients with abnormal uterine bleeding Some ...

  1. Ultrasound -- Pelvis

    Full Text Available ... frequently used to evaluate the reproductive and urinary systems. Ultrasound is safe, ... the sounds that bounce back and a computer then uses those sound waves to create an ...

  2. Hip Ultrasound

    ... Infant ultrasound can be used to check the hips for developmental dysplasia of the hip (DDH), which in infants can range from a shallow cup (bony acetabular dysplasia), to complete dislocation with the ball of the ...

  3. Ultrasound -- Pelvis

    Full Text Available ... in the abdomen, arms, legs, neck and/or brain (in infants and children) or within various body organs ... or uterine cancers A transvaginal ultrasound is usually performed to view ...

  4. Ultrasound -- Pelvis

    Full Text Available ... of urinary and reproductive system disorders in both sexes without even the minimal risks associated with x- ... have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Sonohysterography Ultrasound - ...

  5. Ultrasound -- Pelvis

    Full Text Available ... are also used to monitor the health and development of an embryo or fetus during pregnancy. See ... ultrasound , there are no known harmful effects on humans. top of ... Radiation Therapy for Gynecologic Cancers Radiation ...

  6. Ultrasound -- Pelvis

    Full Text Available ... is pressed against the skin, it directs small pulses of inaudible, high-frequency sound waves into the ... ultrasound study is performed, you may actually hear pulse-like sounds that change in pitch as the ...

  7. Ultrasound -- Pelvis

    Full Text Available ... the patient. Because ultrasound images are captured in real-time, they can show the structure and movement ... by a computer, which in turn creates a real-time picture on the monitor. One or more ...

  8. Ultrasound -- Pelvis

    Full Text Available ... tip of the transducer is smaller than the standard speculum used when performing a Pap test . A ... risks associated with x-ray exposure. Risks For standard diagnostic ultrasound , there are no known harmful effects ...

  9. Ultrasound -- Pelvis

    Full Text Available ... uterine cavity . Three-dimensional (3-D) ultrasound permits evaluation of the uterus and ovaries in planes that ... physicians with expertise in several radiologic areas. Outside links: For the convenience of our users, RadiologyInfo .org ...

  10. Ultrasound -- Pelvis

    Full Text Available ... to-use and less expensive than other imaging methods. Ultrasound imaging is extremely safe and does not ... barium exams, CT scanning , and MRI are the methods of choice in such a setting. Large patients ...

  11. Ultrasound -- Pelvis

    Full Text Available ... legs, neck and/or brain (in infants and children) or within various body organs such as the ... tumors other disorders of the urinary bladder In children, pelvic ultrasound can help evaluate: pelvic masses pelvic ...

  12. Ultrasound -- Pelvis

    Full Text Available ... stable or changes over time. top of page Benefits Most ultrasound scanning is noninvasive (no needles or ... the possible charges you will incur. Web page review process: This Web page is reviewed regularly by ...

  13. Ultrasound -- Pelvis

    Full Text Available ... 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 ...

  14. Ultrasound -- Pelvis

    Full Text Available ... ultrasound exams are also used to monitor the health and development of an embryo or fetus during ... and send a signed report to your primary care physician, or to the physician or other healthcare ...

  15. Ultrasound -- Pelvis

    Full Text Available ... object is solid or filled with fluid). In medicine, ultrasound is used to detect changes in appearance, ... and evaluate a variety of urinary and reproductive system disorders in both sexes without even the minimal ...

  16. Ultrasound -- Pelvis

    Full Text Available ... prior to the exam. Bringing books, small toys, music or games can help to distract the child ... time to the procedure. If a Doppler ultrasound study is performed, you may actually hear pulse-like ...

  17. Ultrasound -- Pelvis

    Full Text Available ... between the transducer and the skin that can block the sound waves from passing into your body. ... to-use and less expensive than other imaging methods. Ultrasound imaging is extremely safe and does not ...

  18. Ultrasound -- Pelvis

    Full Text Available ... frequently used to evaluate the reproductive and urinary systems. Ultrasound is safe, noninvasive and does not use ... and evaluate a variety of urinary and reproductive system disorders in both sexes without even the minimal ...

  19. Ultrasound -- Pelvis

    Full Text Available ... to the child prior to the exam. Bringing books, small toys, music or games can help to ... ultrasound , there are no known harmful effects on humans. top of ... Radiation Therapy for Gynecologic Cancers Radiation ...

  20. Ultrasound -- Pelvis

    Full Text Available ... can help identify: kidney stones bladder tumors other disorders of the urinary bladder In children, pelvic ultrasound ... evaluate a variety of urinary and reproductive system disorders in both sexes without even the minimal risks ...

  1. Ultrasound -- Pelvis

    Full Text Available ... for men). These exams are frequently used to evaluate the reproductive and urinary systems. Ultrasound is safe, ... technique that allows the physician to see and evaluate blood flow through arteries and veins in the ...

  2. Ultrasound -- Pelvis

    Full Text Available ... and movement of the body's internal organs, as well as blood flowing through blood vessels. Ultrasound imaging ... the device used to examine the patient), as well as the type of body structure and composition ...

  3. Ultrasound - Scrotum

    ... tube immediately next to a testicle that collects sperm) and scrotum. Ultrasound is safe, noninvasive, and does ... tube immediately next to a testis that collects sperm made by the testicle) and scrotum. This study ...

  4. Ultrasound -- Pelvis

    Full Text Available ... the examination process. To ensure a smooth experience, it often helps to explain the procedure to the ... on the amplitude (loudness), frequency (pitch) and time it takes for the ultrasound signal to return from ...

  5. Ultrasound -- Pelvis

    Full Text Available ... probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ... small amount of gel is put on the skin to allow the sound waves to best travel ...

  6. Ultrasound -- Pelvis

    Full Text Available ... associated with x-ray exposure. Risks For standard diagnostic ultrasound , there are no known harmful effects on ... by: Please note RadiologyInfo.org is not a medical facility. Please contact your physician with specific medical ...

  7. Hybrid Beamforming and Steering With Reconfigurable Arrays

    Hooi, Fong Ming; Thomenius, Kai E.; Fisher, Rayette; Carson, Paul L.

    2010-01-01

    Reconfigurable arrays offer an advantage over traditional ultrasound arrays because of their flexibility in channel selection. To improve ultrasound beamforming and coverage through beam steering, we propose a hybrid beamforming technique to elongate the depth of focus of transmit beams and a method of element selection that improves steering capabilities that take advantage of array reconfigurability using annular rings. A local minimization technique to optimize the hybrid aperture is discu...

  8. General Ultrasound Imaging

    Full Text Available ... guide biopsy of breast cancer ( see the Ultrasound-Guided Breast Biopsy page . diagnose a variety of heart ... Articles and Media Angioplasty and Vascular Stenting Ultrasound-Guided Breast Biopsy Obstetric Ultrasound Ultrasound - Prostate Biopsies - Overview ...

  9. Ultrasound-assisted matrix solid phase dispersive extraction for the simultaneous analysis of β-lactams (four penicillins and eight cephalosporins) in milk by high performance liquid chromatography with photodiode array detection.

    Karageorgou, Eftichia G; Samanidou, Victoria F; Papadoyannis, Ioannis N

    2012-10-01

    The application of ultrasound-assisted matrix solid phase dispersive extraction for the confirmatory analysis of 12 β-lactam antibiotics in milk by high performance liquid chromatography with photodiode array detection has been proposed herein. Four penicillins (cloxacillin, dicloxacillin, oxacillin, and amoxicillin) and eight cephalosporins (cefaclor, cefadroxil, ceftiofur, cefuroxime, cefoperazone, cefazolin, cephalexin, and cefotaxime) are effectively extracted using a mixed sorbent of Quick Easy Cheap Effective Rugged Safe technique and OASIS HLB providing a matrix free from any endogenous interference. Examined analytes were well resolved on an Inertsil ODS-3 analytical column with a mobile phase of CH(3)COONH(4) (0.05 M) and acetonitrile delivered under a gradient program. 1,7-Dimethyl-xanthine was used as internal standard. The method was validated meeting the European Legislation determining linearity, selectivity, stability, decision limit, detection capability, accuracy, precision, and ruggedness according to the Youden approach. Recoveries of all antibiotics rated from 85.0 to 115.7%, while RSD values were <12.7%. Finally, the method was successfully applied to milk samples purchased from local market. PMID:22941669

  10. Therapeutic ultrasound

    Crum, Lawrence A [Center for Industrial and Medical Ultrasound, 1013 NE 40th Street, University of Washington, Seattle, WA 98105 (United States)

    2004-01-01

    The use of ultrasound in medicine is now quite commonplace, especially with the recent introduction of small, portable and relatively inexpensive, hand-held diagnostic imaging devices. Moreover, ultrasound has expanded beyond the imaging realm, with methods and applications extending to novel therapeutic and surgical uses. These applications broadly include: tissue ablation, acoustocautery, lipoplasty, site-specific and ultrasound mediated drug activity, extracorporeal lithotripsy, and the enhancement of natural physiological functions such as wound healing and tissue regeneration. A particularly attractive aspect of this technology is that diagnostic and therapeutic systems can be combined to produce totally non-invasive, imageguided therapy. This general lecture will review a number of these exciting new applications of ultrasound and address some of the basic scientific questions and future challenges in developing these methods and technologies for general use in our society. We shall particularly emphasize the use of High Intensity Focused Ultrasound (HIFU) in the treatment of benign and malignant tumors as well as the introduction of acoustic hemostasis, especially in organs which are difficult to treat using conventional medical and surgical techniques. (amum lecture)

  11. Therapeutic ultrasound

    The use of ultrasound in medicine is now quite commonplace, especially with the recent introduction of small, portable and relatively inexpensive, hand-held diagnostic imaging devices. Moreover, ultrasound has expanded beyond the imaging realm, with methods and applications extending to novel therapeutic and surgical uses. These applications broadly include: tissue ablation, acoustocautery, lipoplasty, site-specific and ultrasound mediated drug activity, extracorporeal lithotripsy, and the enhancement of natural physiological functions such as wound healing and tissue regeneration. A particularly attractive aspect of this technology is that diagnostic and therapeutic systems can be combined to produce totally non-invasive, imageguided therapy. This general lecture will review a number of these exciting new applications of ultrasound and address some of the basic scientific questions and future challenges in developing these methods and technologies for general use in our society. We shall particularly emphasize the use of High Intensity Focused Ultrasound (HIFU) in the treatment of benign and malignant tumors as well as the introduction of acoustic hemostasis, especially in organs which are difficult to treat using conventional medical and surgical techniques. (amum lecture)

  12. Quantitative Ultrasound Measurements at the Heel

    Daugschies, M.; Brixen, K.; Hermann, P.;

    2015-01-01

    Calcaneal quantitative ultrasound can be used to predict osteoporotic fracture risk, but its ability to monitor therapy is unclear possibly because of its limited precision. We developed a quantitative ultrasound device (foot ultrasound scanner) that measures the speed of sound at the heel...... with the aim of minimizing common error sources like the position and penetration angle of the ultrasound beam, as well as the soft tissue temperature. To achieve these objectives, we used a receiver array, mechanics to adjust the beam direction and a foot temperature sensor. In a group of 60 volunteers, short......-term precision was evaluated for the foot ultrasound scanner and a commercial device (Achilles Insight, GE Medical, Fairfield, CT, USA). In a subgroup of 20 subjects, mid-term precision (1-mo follow-up) was obtained. Compared with measurement of the speed of sound with the Achilles Insight, measurement...

  13. Ultrasound -- Pelvis

    Full Text Available ... to the child prior to the exam. Bringing books, small toys, music or games can help to distract the child and make the time pass quickly. The ultrasound exam room may have a television. Feel free to ask for your child's favorite channel. top ...

  14. Ultrasound -- Pelvis

    Full Text Available ... have a television. Feel free to ask for your child's favorite channel. top of page What does the equipment look like? Ultrasound scanners consist ... your side, facing away from the examiner, with your knees and hips slightly ... page What will I experience during and after the procedure? ...

  15. Ultrasound -- Pelvis

    Full Text Available ... sometimes seen in infections top of page How should I prepare? You should wear comfortable, loose-fitting clothing for your ultrasound ... a cause of pelvic pain, the sonogram itself should not be painful or significantly increase your discomfort. ...

  16. Ultrasound -- Pelvis

    Full Text Available ... Safety En Español More Info Images/Videos News Physician Resources Professions Site Index A-Z Ultrasound - Pelvis ... imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. There are three ...

  17. Ultrasound -- Pelvis

    Full Text Available ... masses such as ovarian cysts and uterine fibroids ovarian or uterine cancers A transvaginal ultrasound is usually performed to view ... Therapy for Gynecologic Cancers Radiation Therapy for Prostate Cancer top ... not be used for any purpose other than this referral.

  18. Ultrasound -- Pelvis

    Full Text Available ... do not use ionizing radiation (as used in x-rays ), thus there is no radiation exposure to the ... tissues that do not show up well on x-ray images. Ultrasound is the preferred imaging modality for ...

  19. Ultrasound -- Pelvis

    Full Text Available ... Radiation Therapy for Gynecologic Cancers Radiation Therapy for Prostate Cancer top of page This page was reviewed on June 12, 2015 Send us your feedback Did you find the information you were looking for? Yes ... - Prostate Images related to Ultrasound - Pelvis About this Site ...

  20. In-situ Attenuation Corrections for Radiation Force Measurements of High Frequency Ultrasound With a Conical Target.

    Fick, Steven E; Ruggles, Dorea

    2006-01-01

    Radiation force balance (RFB) measurements of time-averaged, spatially-integrated ultrasound power transmitted into a reflectionless water load are based on measurements of the power received by the RFB target. When conical targets are used to intercept the output of collimated, circularly symmetric ultrasound sources operating at frequencies above a few megahertz, the correction for in-situ attenuation is significant, and differs significantly from predictions for idealized circumstances. Empirical attenuation correction factors for a 45° (half-angle) absorptive conical RFB target have been determined for 24 frequencies covering the 5 MHz to 30 MHz range. They agree well with previously unpublished attenuation calibration factors determined in 1994 for a similar target. PMID:27274946

  1. Harmonic ultrasound imaging using synthetic aperture sequential beamforming

    2012-01-01

    A method includes generating an ultrasound image based on the harmonic components in the received echoes using multi-stage beam forming and data generated therefrom. An ultrasound imaging system (100, 200) includes a transducer array (108) including a plurality of transducer elements configured t...... ultrasound imaging system further includes a synthetic aperture processor (128), including a second beam former (130) configured to process the stored intermediate scan lines, based on a synthetic aperture algorithm, generating a focused image....

  2. General Ultrasound Imaging

    Full Text Available ... data into 3-D images. A Doppler ultrasound study may be part of an ultrasound examination. Doppler ... not stain or discolor clothing. In some ultrasound studies, the transducer is attached to a probe and ...

  3. General Ultrasound Imaging

    Full Text Available ... of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats the sound wave data into 3-D images. A Doppler ultrasound study may be ...

  4. Ultrasound guided supraclavicular block.

    Hanumanthaiah, Deepak

    2013-09-01

    Ultrasound guided regional anaesthesia is becoming increasingly popular. The supraclavicular block has been transformed by ultrasound guidance into a potentially safe superficial block. We reviewed the techniques of performing supraclavicular block with special focus on ultrasound guidance.

  5. Children's (Pediatric) Abdominal Ultrasound Imaging

    Full Text Available ... Resources Professions Site Index A-Z Children's (Pediatric) Ultrasound - Abdomen Children’s (pediatric) ultrasound imaging of the abdomen ... limitations of Abdominal Ultrasound Imaging? What is Abdominal Ultrasound Imaging? Ultrasound is safe and painless, and produces ...

  6. Ultrasound Imaging. Chapter 13

    In the conventional method of ultrasonography, images are acquired in reflection, or pulse echo, mode. An array of small piezoelectric elements transmits a focused pulse along a specified line of sight known as a scan line. Echoes returning from the tissue are received by the same array, focused via the delay-and-sum beam forming process reviewed in Section 13.2, and demodulated to obtain the magnitude, or envelope, of the echo signal. The scanner measures the arrival time of the echoes relative to the time the pulse was transmitted and maps the arrival time to the distance from the array, using an assumed speed of sound. The earliest ultrasound systems would display the result of a single pulse acquisition in 1-D A-mode (amplitude mode) format by plotting echo magnitude as a function of distance. A 2-D or 3-D B-mode (brightness mode) image is acquired by performing a large number of pulse echo acquisitions, incrementally increasing the scan line direction between each pulse echo operation, to sweep out a 2-D or 3-D field of view (FOV). The term B-mode imaging reflects the fact that the echo magnitude from each point in the FOV is mapped to the grey level, or brightness, of the corresponding pixel in the image

  7. General Ultrasound Imaging

    Full Text Available ... through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. Conventional ultrasound displays the images in thin, ...

  8. Eye and orbit ultrasound

    Echography - eye orbit; Ultrasound - eye orbit; Ocular ultrasonography; Orbital ultrasonography ... ophthalmology department of a hospital or clinic. Your eye is numbed with medicine (anesthetic drops). The ultrasound ...

  9. Signal Processing in Medical Ultrasound B-mode Imaging

    Ultrasonic imaging is the most widely used modality among modern imaging device for medical diagnosis and the system performance has been improved dramatically since early 90's due to the rapid advances in DSP performance and VLSI technology that made it possible to employ more sophisticated algorithms. This paper describes 'main stream' digital signal processing functions along with the associated implementation considerations in modern medical ultrasound imaging systems. Topics covered include signal processing methods for resolution improvement, ultrasound imaging system architectures, roles and necessity of the applications of DSP and VLSI technology in the development of the medical ultrasound imaging systems, and array signal processing techniques for ultrasound focusing

  10. Hippocampal culture stimulus with 4-megahertz ultrasound

    Muratore, Robert; LaManna, Justine K.; Lamprecht, Michael R.; Morrison, Barclay, III

    2012-10-01

    Among current modalities, ultrasound uniquely offers both millisecond and millimeter accuracy in noninvasively stimulating brain tissue. In addition, by sweeping the ultrasound beam within the refractory period of the neuronal tissue, ultrasonic neuromodulation can be adapted to target extended or multiply connected regions with quasi-simultaneity. Towards the development of this safe brain stimulus technique, the response of rat hippocampal cultures to ultrasound was investigated. Hippocampal slices, 0.4-mm thick, were obtained from 8-day old Sprague Dawley rats and cultured for 6 days. The in vitro cultures were exposed to multiple 100-ms 4.04-MHz ultrasound pulses from a 42-mm diameter, 90-mm spherical cap transducer. Peak pressure ranged from 0 through about 77 kPa. Responses in the form of electrical potentials from a sixty channel electrode array were digitized and recorded. The DG and CA1 regions of the hippocampus exhibited similar ultrasonically-evoked field potentials.

  11. Ultrasound and Therapy

    Lafon, Cyril

    This paper begins with an overview and a description of the interactions between ultrasound and biological tissues encountered during treatment protocols. In a second part of this seminar, two clinical applications of therapeutic ultrasound will be described in details: -Kidney stone destruction by ultrasound (lithotripsy) and High Intensity Focused Ultrasound for treating prostate cancer (HIFU).

  12. Ultrasound in Space Medicine

    Dulchavsky, Scott A.; Sargsyan, A.E.

    2009-01-01

    This slide presentation reviews the use of ultrasound as a diagnostic tool in microgravity environments. The goals of research in ultrasound usage in space environments are: (1) Determine accuracy of ultrasound in novel clinical conditions. (2) Determine optimal training methodologies, (3) Determine microgravity associated changes and (4) Develop intuitive ultrasound catalog to enhance autonomous medical care. Also uses of Ultrasound technology in terrestrial applications are reviewed.

  13. Clinical ultrasound physics

    Abu-Zidan, Fikri M; Hefny, Ashraf F; Corr, Peter

    2011-01-01

    Understanding the basic physics of ultrasound is essential for acute care physicians. Medical ultrasound machines generate and receive ultrasound waves. Brightness mode (B mode) is the basic mode that is usually used. Ultrasound waves are emitted from piezoelectric crystals of the ultrasound transducer. Depending on the acoustic impedance of different materials, which depends on their density, different grades of white and black images are produced. There are different methods that can contro...

  14. Non-linear Ultrasound Imaging

    Du, Yigang

    The theory for modeling non-linear acoustic propagation is addressed in the dissertation. The solutions to both the linear and non-linear wave equations have been found by an angular spectrum approach (ASA), in which an analytical expression can be derived. This makes the calculation complete...... without iteration steps. The ASA is implemented in combination with Field II and extended to simulate the pulsed ultrasound fields. The simulated results from a linear array transducer are made by the ASA based on Field II, and by a released non-linear simulation program- Abersim, respectively. The...... calculation speed of the ASA is increased approximately by a factor of 140. For the second harmonic point spread function the error of the full width is 1.5% at -6 dB and 6.4% at -12 dB compared to Abersim. To further investigate the linear and non-linear ultrasound fields, hydrophone measurements are...

  15. Volumetric Flow Measurement Using an Implantable CMUT Array.

    Mengli Wang; Jingkuang Chen

    2011-06-01

    This paper describes volumetric-flow velocity measurement using an implantable capacitive micromachined ultrasonic transducer (CMUT) array. The array is comprised of multiple-concentric CMUT rings for ultrasound transmission and an outmost annular CMUT array for ultrasound reception. Microelectromechanical-system (MEMS) fabrication technology allows reception CMUT on this flowmeter to be implemented with a different membrane thickness and gap height than that of transmission CMUTs, optimizing the performance of these two different kinds of devices. The silicon substrate of this 2-mm-diameter CMUT ring array was bulk micromachined to approximately 80 to 100 μm thick, minimizing tissue disruption. The blood-flow velocity was detected using pulse ultrasound Doppler by comparing the demodulated echo ultrasound with the incident ultrasound. The demodulated ultrasound signal was sampled by a pulse delayed in time domain from the transmitted burst, which corresponds to detecting the signal at a specific distance. The flow tube/vessel diameter was detected through the time-flight delay difference from near and far wall reflections, which was measured from the ultrasound pulse echo. The angle between the ultrasound beam and the flow was found by using the cross-correlation from consecutive ultrasound echoes. Artificial blood flowing through three different polymer tubes was experimented with, while keeping the same volumetric flow rate. The discrepancy in flow measurement results between this CMUT meter and a calibrated laser Doppler flowmeter is less than 5%. PMID:23851472

  16. Fundamentals of ultrasonic phased arrays

    Schmerr, Lester W

    2014-01-01

    This book describes in detail the physical and mathematical foundations of ultrasonic phased array measurements.?The book uses linear systems theory to develop a comprehensive model of the signals and images that can be formed with phased arrays. Engineers working in the field of ultrasonic nondestructive evaluation (NDE) will find in this approach a wealth of information on how to design, optimize and interpret ultrasonic inspections with phased arrays. The fundamentals and models described in the book will also be of significant interest to other fields, including the medical ultrasound and

  17. Prenatal ultrasound - slideshow

    ... this page: //medlineplus.gov/ency/presentations/100197.htm Prenatal ultrasound - series To use the sharing features on ... A.M. Editorial team. Related MedlinePlus Health Topics Prenatal Testing Ultrasound A.D.A.M., Inc. is ...

  18. General Ultrasound Imaging

    Full Text Available ... General Ultrasound Videos related to General Ultrasound About this Site RadiologyInfo.org is produced by: Please note ... you can search the ACR-accredited facilities database . This website does not provide cost information. The costs ...

  19. General Ultrasound Imaging

    Full Text Available ... medicine, ultrasound is used to detect changes in appearance, size or contour of organs, tissues, and vessels or to detect abnormal masses, such as tumors. In an ultrasound examination, a transducer both sends ...

  20. General Ultrasound Imaging

    Full Text Available ... top of page What are the benefits vs. risks? Benefits Most ultrasound scanning is noninvasive (no needles ... procedures such as needle biopsies and fluid aspiration. Risks For standard diagnostic ultrasound , there are no known ...

  1. General Ultrasound Imaging

    ... The ultrasound gel does not stain or discolor clothing. In some ultrasound studies, the transducer is attached to a probe and inserted into a natural opening in the body. These exams include: Transesophageal ...

  2. General Ultrasound Imaging

    Full Text Available ... again. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... ultrasound , there are no known harmful effects on humans. top of page What are the limitations of ...

  3. General Ultrasound Imaging

    Full Text Available ... technique that allows the physician to see and evaluate blood flow through arteries and veins in the ... following illness. Ultrasound is used to help physicians evaluate symptoms such as: pain swelling infection Ultrasound is ...

  4. Advanced 3-D Ultrasound Imaging

    Rasmussen, Morten Fischer

    been completed. This allows for precise measurements of organs dimensions and makes the scan more operator independent. Real-time 3-D ultrasound imaging is still not as widespread in use in the clinics as 2-D imaging. A limiting factor has traditionally been the low image quality achievable using...... and removes the need to integrate custom made electronics into the probe. A downside of row-column addressing 2-D arrays is the creation of secondary temporal lobes, or ghost echoes, in the point spread function. In the second part of the scientific contributions, row-column addressing of 2-D arrays...... was investigated. An analysis of how the ghost echoes can be attenuated was presented.Attenuating the ghost echoes were shown to be achieved by minimizing the first derivative of the apodization function. In the literature, a circular symmetric apodization function was proposed. A new apodization layout...

  5. Modeling of ultrasound transducers

    Bæk, David

    This Ph.D. dissertation addresses ultrasound transducer modeling for medical ultrasound imaging and combines the modeling with the ultrasound simulation program Field II. The project firstly presents two new models for spatial impulse responses (SIR)s to a rectangular elevation focused transducer...

  6. Harmonic Intravascular Ultrasound

    M.E. Frijlink (Martijn)

    2006-01-01

    textabstractMedical ultrasound is a popular imaging modality in cardiology. Harmonic Imaging is a technique that has been shown to increase the image quality of diagnostic ultrasound at frequencies below 10 MHz. However, Intravascular Ultrasound, which is a technique to acoustically investigate arte

  7. Broadband miniature optical ultrasound probe for high resolution vascular tissue imaging.

    Colchester, R. J.; Zhang, E. Z.; Mosse, C. A.; Beard, P.C.; Papakonstantinou, I.; Desjardins, A. E.

    2015-01-01

    An all-optical ultrasound probe for vascular tissue imaging was developed. Ultrasound was generated by pulsed laser illumination of a functionalized carbon nanotube composite coating on the end face of an optical fiber. Ultrasound was detected with a Fabry-Pérot (FP) cavity on the end face of an adjacent optical fiber. The probe diameter was < 0.84 mm and had an ultrasound bandwidth of ~20 MHz. The probe was translated across the tissue sample to create a virtual linear array of ultrasound tr...

  8. Neonatal cranial ultrasound: current perspectives

    Franco A

    2013-09-01

    Full Text Available Arie Franco, Kristopher Neal Lewis Department of Radiology, Medical College of Georgia at Georgia Regents University, Augusta, GA, USA Abstract: Ultrasound is the most common imaging tool used in the neonatal intensive care unit. It is portable, readily available, and can be used at bedside. It is the least expensive cross sectional imaging modality and the safest imaging device used in the pediatric population due to its lack of ionizing radiation. There are well established indications for cranial ultrasound in many neonatal patient groups including preterm infants and term infants with birth asphyxia, seizures, congenital infections, etc. Cranial ultrasound is performed with basic grayscale imaging, using a linear array or sector transducer via the anterior fontanel in the coronal and sagittal planes. Additional images can be obtained through the posterior fontanel in preterm newborns. The mastoid fontanel can be used for assessment of the posterior fossa. Doppler images may be obtained for screening of the vascular structures. The normal sonographic neonatal cranial anatomy and normal variants are discussed. The most common pathological findings in preterm newborns, such as germinal matrix-intraventricular hemorrhage and periventricular leukomalacia, are described as well as congenital abnormalities such as holoprosencephaly and agenesis of the corpus callosum. New advances in sonographic equipment enable high-resolution and three-dimensional images, which facilitate obtaining very accurate measurements of various anatomic structures such as the ventricles, the corpus callosum, and the cerebellar vermis. Limited studies have been performed to predict that longitudinal measurements of these anatomic structures might predict the clinical outcome of high-risk preterm newborns. Hemodynamic Doppler studies may offer the potential for early intervention and treatment to counter the hazards of developmental delay and a moribund clinical outcome

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

    Meola, Mario; Petrucci, Ilaria

    2012-01-01

    Sonography is an imaging technique that generates tomographic images using ultrasound. The sound constitutes mechanical energy transmitted in a medium by pressure waves. Sound waves with frequencies greater than 20 kHz are called ultrasounds. Diagnostic ultrasounds use frequencies from 1 to 20 MHz. Ultrasound equipment is composed of a scanner, an image monitor, and different transducers that transform acoustic energy into electrical signals and electrical energy into acoustic energy (piezoelectric effect). The spatial resolution defines the minimum distance between two reflectors or echogenic regions that can be imaged as separate reflectors. The spatial resolution is mainly determined by the array design (linear, curved and sectorial) and by the operative system of the transducer. Modern ultrasound machines are very sophisticated medical devices that often support many transducers, imaging modes and display devices. The scan converter memory is the device in which images are formed and then presented to the monitor and to the hard copy devices. PMID:22388909

  10. Obstetric ultrasound simulation.

    Nitsche, Joshua F; Brost, Brian C

    2013-06-01

    Obstetric ultrasound is becoming an increasingly important part of the practice of maternal-fetal medicine. Thus, it is important to develop rigorous and effective training curricula for obstetrics and gynecology residents and maternal-fetal medicine fellows. Traditionally, this training has come almost entirely from exposure to ultrasound in the clinical setting. However, with the increased complexity of modern ultrasound and advent of duty-hour restrictions, a purely clinical training model is no longer viable. With the advent of high-fidelity obstetric ultrasound simulators, a significant amount of training can occur in a non-clinical setting which allows learners to obtain significant skill prior to their first patient ultrasound encounter and obtain proficiency in a shorter period of time. In this manuscript we discuss the available obstetric ultrasound simulators and ways to construct a comprehensive ultrasound training curricula to meet the increasing demands of modern maternal-fetal medicine. PMID:23721777

  11. Angular Spectrum Simulation of Pulsed Ultrasound Fields

    Du, Yigang; Jensen, Henrik; Jensen, Jørgen Arendt

    The optimization of non-linear ultrasound imaging should in a first step be based on simulation, as this makes parameter studies considerably easier than making transducer prototypes. Such a simulation program should be capable of simulating non-linear pulsed fields for arbitrary transducer...... geometries for any kind of focusing and apodization. The Angular Spectrum Approach (ASA) is capable of simulating monochromatic non-linear acoustic wave propagation. However, for ultrasound imaging the time response of each specific point in space is required, and a pulsed ASA simulation with multi temporal...... frequencies must be performed. Combining it with Field II, the generation of non-linear simulation for any geometry with any excitation array transducer becomes feasible. The purpose of this paper is to make a general pulsed simulation software using the modified ASA. Linear and phased array transducers are...

  12. TU-A-9A-06: Semi-Automatic Segmentation of Skin Cancer in High-Frequency Ultrasound Images: Initial Comparison with Histology

    Gao, Y [Univ. Alabama at Birmingham, Birmingham, AL (United States); Li, X [Medical College of Wisconsin, Milwaukee, WI (United States); Fishman, K [Sensus Healthcare, Boca Raton, FL (United States); Yang, X [Department of Radiation Oncology and Winship Cancer Institute, Emory Univ., Atlanta, GA (United States); Liu, T [Emory Univ, Atlanta, GA (United States)

    2014-06-15

    Purpose: In skin-cancer radiotherapy, the assessment of skin lesion is challenging, particularly with important features such as the depth and width hard to determine. The aim of this study is to develop interative segmentation method to delineate tumor boundary using high-frequency ultrasound images and to correlate the segmentation results with the histopathological tumor dimensions. Methods: We analyzed 6 patients who comprised a total of 10 skin lesions involving the face, scalp, and hand. The patient’s various skin lesions were scanned using a high-frequency ultrasound system (Episcan, LONGPORT, INC., PA, U.S.A), with a 30-MHz single-element transducer. The lateral resolution was 14.6 micron and the axial resolution was 3.85 micron for the ultrasound image. Semiautomatic image segmentation was performed to extract the cancer region, using a robust statistics driven active contour algorithm. The corresponding histology images were also obtained after tumor resection and served as the reference standards in this study. Results: Eight out of the 10 lesions are successfully segmented. The ultrasound tumor delineation correlates well with the histology assessment, in all the measurements such as depth, size, and shape. The depths measured by the ultrasound have an average of 9.3% difference comparing with that in the histology images. The remaining 2 cases suffered from the situation of mismatching between pathology and ultrasound images. Conclusion: High-frequency ultrasound is a noninvasive, accurate and easy-accessible modality to image skin cancer. Our segmentation method, combined with high-frequency ultrasound technology, provides a promising tool to estimate the extent of the tumor to guide the radiotherapy procedure and monitor treatment response.

  13. TU-A-9A-06: Semi-Automatic Segmentation of Skin Cancer in High-Frequency Ultrasound Images: Initial Comparison with Histology

    Purpose: In skin-cancer radiotherapy, the assessment of skin lesion is challenging, particularly with important features such as the depth and width hard to determine. The aim of this study is to develop interative segmentation method to delineate tumor boundary using high-frequency ultrasound images and to correlate the segmentation results with the histopathological tumor dimensions. Methods: We analyzed 6 patients who comprised a total of 10 skin lesions involving the face, scalp, and hand. The patient’s various skin lesions were scanned using a high-frequency ultrasound system (Episcan, LONGPORT, INC., PA, U.S.A), with a 30-MHz single-element transducer. The lateral resolution was 14.6 micron and the axial resolution was 3.85 micron for the ultrasound image. Semiautomatic image segmentation was performed to extract the cancer region, using a robust statistics driven active contour algorithm. The corresponding histology images were also obtained after tumor resection and served as the reference standards in this study. Results: Eight out of the 10 lesions are successfully segmented. The ultrasound tumor delineation correlates well with the histology assessment, in all the measurements such as depth, size, and shape. The depths measured by the ultrasound have an average of 9.3% difference comparing with that in the histology images. The remaining 2 cases suffered from the situation of mismatching between pathology and ultrasound images. Conclusion: High-frequency ultrasound is a noninvasive, accurate and easy-accessible modality to image skin cancer. Our segmentation method, combined with high-frequency ultrasound technology, provides a promising tool to estimate the extent of the tumor to guide the radiotherapy procedure and monitor treatment response

  14. Space-based Aperture Array For Ultra-Long Wavelength Radio Astronomy

    Rajan, Raj Thilak; Bentum, Mark; Klein-Wolt, Marc; Belien, Frederik; Arts, Michel; Saks, Noah; van der Veen, Alle-Jan

    2015-01-01

    The past decade has seen the rise of various radio astronomy arrays, particularly for low-frequency observations below 100MHz. These developments have been primarily driven by interesting and fundamental scientific questions, such as studying the dark ages and epoch of re-ionization, by detecting the highly red-shifted 21cm line emission. However, Earth-based radio astronomy below frequencies of 30MHz is severely restricted due to man-made interference, ionospheric distortion and almost complete non-transparency of the ionosphere below 10MHz. Therefore, this narrow spectral band remains possibly the last unexplored frequency range in radio astronomy. A straightforward solution to study the universe at these frequencies is to deploy a space-based antenna array far away from Earths' ionosphere. Various studies in the past were principally limited by technology and computing resources, however current processing and communication trends indicate otherwise. We briefly present the achievable science cases, and dis...

  15. Ultrasound imaging probe with sigma-delta beamformer and apodization therein

    2014-01-01

    An ultrasound transducer probe (104) includes a transducer array (108) of elements ( 1 10) that emit an ultrasound signal and receive analog echo signals produced in response thereto and a beamformer (1 12), housed by the probe, that converts the analog echo signals to digital signals, applies de...

  16. Use of ultrasound in the management of thyroid cancer.

    Lew, John I; Solorzano, Carmen C

    2010-01-01

    The use of ultrasound for thyroid cancer has evolved dramatically over the last few decades. Since the late 1960s, ultrasound has become essential in the examination of the thyroid gland with the increased availability of high-frequency linear array transducers and computer-enhanced imaging capabilities of modern day portable ultrasound equipment in a clinic- or office-based setting. As a noninvasive, rapid, and easily reproducible imaging study, ultrasound has been demonstrated to have a broadened utility beyond the simple confirmation of thyroid nodules and their sizes. Recently, office-based ultrasound has become an integral part of clinical practice, where it has demonstrated overwhelming benefits to patients being evaluated and treated for thyroid cancer. Ultrasound has become useful in the qualitative characterization of thyroid nodules based on benign or malignant features. On the basis of such classifications and the relative risk for thyroid malignancy, the need for ultrasound-guided fine-needle aspiration, preoperative and intraoperative staging, lymph node mapping, and the extent of surgery can subsequently be determined. Furthermore, ultrasound has additional value in the surveillance of patients treated for thyroid cancer. PMID:20215358

  17. Children's (Pediatric) Abdominal Ultrasound Imaging

    Full Text Available ... located within a child's abdomen. A Doppler ultrasound study may be part of a child's abdominal ultrasound ... pain from the procedure. If a Doppler ultrasound study is performed, your child may actually hear pulse- ...

  18. Ultrasound-Guided Breast Biopsy

    ... Professions Site Index A-Z Ultrasound-Guided Breast Biopsy An ultrasound-guided breast biopsy uses sound waves ... Guided Breast Biopsy? What is Ultrasound-Guided Breast Biopsy? Lumps or abnormalities in the breast are often ...

  19. Medical ultrasound imaging

    Jensen, Jørgen Arendt

    2007-01-01

    The paper gives an introduction to current medical ultrasound imaging systems. The basics of anatomic and blood flow imaging are described. The properties of medical ultrasound and its focusing are described, and the various methods for two- and three-dimensional imaging of the human anatomy are...... shown. Both systems using linear and non-linear propagation of ultrasound are described. The blood velocity can also be non-invasively visualized using ultrasound and the basic signal processing for doing this is introduced. Examples for spectral velocity estimation, color flow maging and the new vector...

  20. Simulation of post-ADC digital beamforming for large aperture array radars

    Johansson, G.; Borg, J.; Johansson, J.; Lundberg Nordenvaad, M.; Wannberg, G.

    2010-06-01

    This paper presents simulations and methods developed to investigate the feasibility of using a Fractional-Sample-Delay (FSD) system in the planned EISCAT_3D incoherent scatter radar. Key requirements include a frequency-independent beam direction over a 30 MHz band centered around 220 MHz, with correct reconstruction of pulse lengths down to 200 ns. The clock jitter from sample to sample must be extremely low for the integer sample delays. The FSD must also be able to delay the 30 MHz wide signal band by 1/1024th of a sample without introducing phase shifts, and it must operate entirely in baseband. An extensive simulation system based on mathematical models has been developed, with inclusion of performance-degrading aspects such as noise, timing error, and bandwidth. Finite Impulse Response (FIR) filters in the baseband of a band-pass-sampled signal have been used to apply true time delay beamforming. It has been confirmed that such use is both possible and well behaved. The target beam-pointing accuracy of 0.06° is achievable using optimized FIR filters with lengths of 36 taps and an 18 bit coefficient resolution. Even though the minimum fractional delay step necessary for beamforming is ˜13.1 ps, the maximum sampling timing error allowed in the array is found to be σ ≤ 120 ps if the errors are close to statistically independent.

  1. Children's (Pediatric) Abdominal Ultrasound Imaging

    Full Text Available ... through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. Children's (pediatric) abdominal ultrasound imaging produces pictures ...

  2. 3D ultrafast ultrasound imaging in vivo

    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. (fast track communication)

  3. Venous Ultrasound (Extremities)

    ... page How is the procedure performed? For most ultrasound exams, you will be positioned lying face-up on an examination table that can be ... either side or on occasion placed in a face down position to improve the quality ... (ultrasound technologist) or radiologist then places the transducer on ...

  4. Compensated Row-Column Ultrasound Imaging System Using Fisher Tippett Multilayered Conditional Random Field Model

    Ibrahim Ben Daya; Albert I H Chen; Mohammad Javad Shafiee; Alexander Wong; John T. W. Yeow

    2015-01-01

    3-D ultrasound imaging offers unique opportunities in the field of non destructive testing that cannot be easily found in A-mode and B-mode images. To acquire a 3-D ultrasound image without a mechanically moving transducer, a 2-D array can be used. The row column technique is preferred over a fully addressed 2-D array as it requires a significantly lower number of interconnections. Recent advances in 3-D row-column ultrasound imaging systems were largely focused on sensor design. However, the...

  5. Adaptive Receive and Transmit Apodization for Synthetic Aperture Ultrasound Imaging

    Holfort, Iben Kraglund; Austeng, Andreas; Synnevåg, Johan-Fredrik;

    2009-01-01

    emission images before summation. The method is investigated using simulated SA ultrasound data obtained using Field II. Data of 13 point targets distributed at depths from 40 mm to 70 mm, and a 5.5 MHz, 64-element linear array transducer have been used. The investigation has shown that the introduction of...

  6. Hepatic applications of endoscopic ultrasound

    Srinivasan, Indu; Tang, Shou-Jiang; Vilmann, Andreas S;

    2015-01-01

    The diagnosis and staging of various gastrointestinal malignancies have been made possible with the use of endoscopic ultrasound, which is a relatively safe procedure. The field of endoscopic ultrasound is fast expanding due to advancements in therapeutic endoscopic ultrasound. Though various...... of endoscopic ultrasound, thus not only providing an overview of utilization of endoscopic ultrasound in various liver conditions but also speculating its future role....

  7. Electronic hardware design for ultrasound Transient Elastography

    Anand Sneh

    2012-08-01

    Full Text Available Transient Elastography, an emerging technique in Medical Ultrasonography has wide spread application in detection of malignant tumors. This non invasive method uses low frequency waves orthogonal to the direction of propagation of ultrasound waves. Piezoelectric crystals in ultrasound probe are excited using high voltage Pulsar which converts digital pulses into high voltages pulses. The pulse parameters are programmed using Field Programmable Gate Array (FPGA. The circuit has separate crystals for transmission, receptioneliminating high voltage multiplexer and TR switch. The receiver section uses integrated circuit having low noise amplifier, time gain compensation, anti aliasing filter & analog to digital convertor and processed in FPGA. Both FPGAs are controlled by microcontroller. Since all channels are received simultaneously, a large data rate transmission through Ethernet interface for real time data interfacing and image processing is required. The speed of the waves travelling in the orthogonal direction can be measured using motion modeling.

  8. Ultrasound transducer assembly and method for manufacturing an ultrasound transducer assembly

    Dekker, R.; Henneken, V.A.; Louwerse, M.C.; Raganato, M.F.

    2015-01-01

    The present invention relates to an ultrasound transducer assembly (10), in particular for intravascular ultrasound systems. The ultrasound transducer assembly comprises at least one silicon substrate element (30) including an ultrasound transducer element (14) for emitting and receiving ultrasound

  9. General Ultrasound Imaging

    Full Text Available ... biopsies , in which needles are used to sample cells from an abnormal area for laboratory testing. image ... ultrasound, measures the direction and speed of blood cells as they move through vessels. The movement of ...

  10. General Ultrasound Imaging

    Full Text Available ... patient. Because ultrasound images are captured in real-time, they can show the structure and movement of ... terms of the distance traveled per unit of time, rather than as a color picture. It can ...

  11. Abdominal ultrasound (image)

    Abdominal ultrasound is a scanning technique used to image the interior of the abdomen. Like the X- ... use high frequency sound waves to produce an image and do not expose the individual to radiation. ...

  12. General Ultrasound Imaging

    Full Text Available ... deeper into the body. Ultrasound has difficulty penetrating bone and, therefore, can only see the outer surface ... children or adults). For visualizing internal structure of bones or certain joints, other imaging modalities such as ...

  13. General Ultrasound Imaging

    Full Text Available ... over time. top of page What are the benefits vs. risks? Benefits Most ultrasound scanning is noninvasive (no needles or ... the possible charges you will incur. Web page review process: This Web page is reviewed regularly by ...

  14. General Ultrasound Imaging

    Full Text Available ... between the transducer and the skin that can block the sound waves from passing into your body. ... to-use and less expensive than other imaging methods. Ultrasound imaging is extremely safe and does not ...

  15. Ultrasound Modulated Bioluminescence Tomography

    Bal, Guillaume

    2013-01-01

    We propose a method to reconstruct the density of a luminescent source in a highly-scattering medium from ultrasound modulated optical measurements. Our approach is based on the solution to a hybrid inverse source problem for the diffusion equation.

  16. Space-based aperture array for ultra-long wavelength radio astronomy

    Rajan, Raj Thilak; Boonstra, Albert-Jan; Bentum, Mark; Klein-Wolt, Marc; Belien, Frederik; Arts, Michel; Saks, Noah; van der Veen, Alle-Jan

    2016-02-01

    The past decade has seen the advent of various radio astronomy arrays, particularly for low-frequency observations below 100 MHz. These developments have been primarily driven by interesting and fundamental scientific questions, such as studying the dark ages and epoch of re-ionization, by detecting the highly red-shifted 21 cm line emission. However, Earth-based radio astronomy observations at frequencies below 30 MHz are severely restricted due to man-made interference, ionospheric distortion and almost complete non-transparency of the ionosphere below 10 MHz. Therefore, this narrow spectral band remains possibly the last unexplored frequency range in radio astronomy. A straightforward solution to study the universe at these frequencies is to deploy a space-based antenna array far away from Earths' ionosphere. In the past, such space-based radio astronomy studies were principally limited by technology and computing resources, however current processing and communication trends indicate otherwise. Furthermore, successful space-based missions which mapped the sky in this frequency regime, such as the lunar orbiter RAE-2, were restricted by very poor spatial resolution. Recently concluded studies, such as DARIS (Disturbuted Aperture Array for Radio Astronomy In Space) have shown the ready feasibility of a 9 satellite constellation using off the shelf components. The aim of this article is to discuss the current trends and technologies towards the feasibility of a space-based aperture array for astronomical observations in the Ultra-Long Wavelength (ULW) regime of greater than 10 m i.e., below 30 MHz. We briefly present the achievable science cases, and discuss the system design for selected scenarios such as extra-galactic surveys. An extensive discussion is presented on various sub-systems of the potential satellite array, such as radio astronomical antenna design, the on-board signal processing, communication architectures and joint space-time estimation of the

  17. Silicon photonic micro-ring resonators to sense strain and ultrasound

    Westerveld, W.J.

    2014-01-01

    We demonstrated that photonic micro-ring resonators can be used in micro-machined ultrasound microphones. This might cause a breakthrough in array transducers for ultrasonography; first because optical multiplexing allows array interrogation via one optical fiber and second because the silicon-on-in

  18. Integrated Interventional Devices For Real Time 3D Ultrasound Imaging and Therapy

    Smith, Stephen W.; Lee, Warren; Gentry, Kenneth L.; Pua, Eric C.; Light, Edward D.

    2006-05-01

    Two recent advances have expanded the potential of medical ultrasound: the introduction of real-time 3-D ultrasound imaging with catheter, transesophageal and laparoscopic probes and the development of interventional ultrasound therapeutic systems for focused ultrasound surgery, ablation and ultrasound enhanced drug delivery. This work describes devices combining both technologies. A series of transducer probes have been designed, fabricated and tested including: 1) a 12 French side scanning catheter incorporating a 64 element matrix array for imaging at 5MHz and a piston ablation transducer operating at 10 MHz. 2) a 14 Fr forward-scanning catheter integrating a 112 element 2-D array for imaging at 5 MHz encircled by an ablation annulus operating at 10 MHz. Finite element modeling was then used to simulate catheter annular and linear phased array transducers for ablation. 3) Linear phased array transducers were built to confirm the finite element analysis at 4 and 8 MHz including a mechanically focused 86 element 9 MHz array which transmits an ISPTA of 29.3 W/cm2 and creates a lesion in 2 minutes. 4) 2-D arrays of 504 channels operating at 5 MHz have been developed for transesophageal and laparascopic 3D imaging as well as therapeutic heating. All the devices image the heart anatomy including atria, valves, septa and en face views of the pulmonary veins.

  19. Ultrasound beamforming using compressed data.

    Li, Yen-Feng; Li, Pai-Chi

    2012-05-01

    The rapid advancements in electronics technologies have made software-based beamformers for ultrasound array imaging feasible, thus facilitating the rapid development of high-performance and potentially low-cost systems. However, one challenge to realizing a fully software-based system is transferring data from the analog front end to the software back end at rates of up to a few gigabits per second. This study investigated the use of data compression to reduce the data transfer requirements and optimize the associated trade-off with beamforming quality. JPEG and JPEG2000 compression techniques were adopted. The acoustic data of a line phantom were acquired with a 128-channel array transducer at a center frequency of 3.5 MHz, and the acoustic data of a cyst phantom were acquired with a 64-channel array transducer at a center frequency of 3.33 MHz. The receive-channel data associated with each transmit event are separated into 8 × 8 blocks and several tiles before JPEG and JPEG2000 data compression is applied, respectively. In one scheme, the compression was applied to raw RF data, while in another only the amplitude of baseband data was compressed. The maximum compression ratio of RF data compression to produce an average error of lower than 5 dB was 15 with JPEG compression and 20 with JPEG2000 compression. The image quality is higher with baseband amplitude data compression than with RF data compression; although the maximum overall compression ratio (compared with the original RF data size), which was limited by the data size of uncompressed phase data, was lower than 12, the average error in this case was lower than 1 dB when the compression ratio was lower than 8. PMID:22434817

  20. Clinical Utility of Endoscopic Ultrasound in Solid Pancreatic Mass Lesions Deemed Resectable by Computer Tomography

    Mark A Virtue

    2008-03-01

    Full Text Available Context Appropriate surgical exploration and resection of pancreatic carcinoma depends on accurate preoperative evaluation. Objective Determine the accuracy of endoscopic ultrasound in predicting the need for surgical exploration in patients with solid pancreatic masses deemed by computer tomography to be resectable without venous grafting (absence of distant metastatic disease or major vascular involvement. Patients All patients between March 2000 and November 2003 with focal pancreatic mass lesions deemed to be surgically resectable by computer tomography. Fortynine patients participated (29 males, 20 females; age range: 40-86 years. Intervention Preoperative linear-array endoscopic ultrasound. Main outcome measure Surgical pathology compared to computer tomography and endoscopic ultrasound results. Results Out of the 49 patients, 33 (67.3% had pancreatic neoplasms and 16 (32.7% had chronic pancreatitis. Endoscopic ultrasound correctly diagnosed all 16 patients with chronic pancreatitis. Endoscopic ultrasound correctly identified 18 (54.5% of those with neoplasms as having unresectable disease while 6 (18.2% patients were appropriately identified as resectable by endoscopic ultrasound. The remaining 9 patients (27.3% were deemed resectable by endoscopic ultrasound, but were unresectable at the time of surgery. None of the patients were falsely designated as unresectable by endoscopic ultrasound. Conclusion Endoscopic ultrasound is an important compliment to computed tomography in predicting resectability and in avoiding nontherapeutic laparotomy of solid pancreatic neoplasms. Moreover, endoscopic ultrasound classification did not discourage surgery of resectable pancreatic masses.

  1. Ultrasound- and MRI-Guided Prostate Biopsy

    ... Index A-Z Ultrasound- and MRI-Guided Prostate Biopsy Ultrasound- and MRI-guided prostate biopsy uses imaging ... Biopsy? What is Ultrasound- and MRI-guided Prostate Biopsy? Ultrasound- and MRI-guided prostate biopsies are performed ...

  2. Assessment of the Kinetic Trajectory of the Median Nerve in the Wrist by High-Frequency Ultrasound

    Yi-Hsun Lin

    2014-04-01

    Full Text Available Carpal tunnel syndrome (CTS is typically diagnosed by physical examination or nerve conduction measurements. With these diagnostics however it is difficult to obtain anatomical information in the carpal tunnel. To further improve the diagnosis of CTS, an attempt using 30 MHz high-frequency ultrasound to noninvasively detect the local anatomical structures and the kinetic trajectory of the median nerve (MN in the wrist was explored. Measurements were performed on the right wrist of 14 asymptomatic volunteers. The kinetic trajectory of the MN corresponding to flexion (from 0° to 90° and extension (from 90° to 0° movements of the fingers were detected by a cross correlation-based motion tracking technique. The average displacements of the MN according to finger movements were measured to be 3.74 and 2.04 mm for male and female subjects, respectively. Moreover, the kinetic trajectory of the MN in both the ulnar-palmar and total directions generally follows a sigmoidal curve tendency. This study has verified that the use of high-frequency ultrasound imaging and a motion tracking technique to sensitively detect the displacement and kinetic trajectory of the MN for the assessment of CTS patients is feasible.

  3. Combined ultrasound and MR imaging to guide focused ultrasound therapies in the brain

    Several emerging therapies with potential for use in the brain, harness effects produced by acoustic cavitation—the interaction between ultrasound and microbubbles either generated during sonication or introduced into the vasculature. Systems developed for transcranial MRI-guided focused ultrasound (MRgFUS) thermal ablation can enable their clinical translation, but methods for real-time monitoring and control are currently lacking. Acoustic emissions produced during sonication can provide information about the location, strength and type of the microbubble oscillations within the ultrasound field, and they can be mapped in real-time using passive imaging approaches. Here, we tested whether such mapping can be achieved transcranially within a clinical brain MRgFUS system. We integrated an ultrasound imaging array into the hemisphere transducer of the MRgFUS device. Passive cavitation maps were obtained during sonications combined with a circulating microbubble agent at 20 targets in the cingulate cortex in three macaques. The maps were compared with MRI-evident tissue effects. The system successfully mapped microbubble activity during both stable and inertial cavitation, which was correlated with MRI-evident transient blood–brain barrier disruption and vascular damage, respectively. The location of this activity was coincident with the resulting tissue changes within the expected resolution limits of the system. While preliminary, these data clearly demonstrate, for the first time, that it is possible to construct maps of stable and inertial cavitation transcranially, in a large animal model, and under clinically relevant conditions. Further, these results suggest that this hybrid ultrasound/MRI approach can provide comprehensive guidance for targeted drug delivery via blood–brain barrier disruption and other emerging ultrasound treatments, facilitating their clinical translation. We anticipate that it will also prove to be an important research tool that

  4. Ultrasound attenuation computed tomography assessment of PAGAT gel dose

    Ultrasound has been previously investigated as an alternative readout method for irradiated polymer gel dosimeters, with authors reporting varying dose responses. We extend previous work utilizing a new computed tomography ultrasound scanner comprising of two identical 5 MHz, 128-element linear-array ultrasound transducers, co-axially aligned and submerged in water as a coupling agent, with rotational of the gel dosimeter between the transducers facilitated by a robotic arm. We have investigated the dose-dependence of both ultrasound bulk attenuation and broadband ultrasound attenuation (BUA) for the PAGAT gel dosimeter. The ultrasound bulk attenuation dose sensitivity was found to be 1.46  ±  0.04 dB m −1 Gy −1, being in agreement with previously published results for PAG and MAGIC gels. BUA was also found to be dose dependent and was measured to be 0.024  ±  0.003 dB MHz −1 Gy −1; the advantage of BUA being its insensitivity to frequency-independent attenuation mechanisms including reflection and refraction, thereby minimizing image reconstruction artefacts. (note)

  5. Synthetic tracked aperture ultrasound imaging: design, simulation, and experimental evaluation.

    Zhang, Haichong K; Cheng, Alexis; Bottenus, Nick; Guo, Xiaoyu; Trahey, Gregg E; Boctor, Emad M

    2016-04-01

    Ultrasonography is a widely used imaging modality to visualize anatomical structures due to its low cost and ease of use; however, it is challenging to acquire acceptable image quality in deep tissue. Synthetic aperture (SA) is a technique used to increase image resolution by synthesizing information from multiple subapertures, but the resolution improvement is limited by the physical size of the array transducer. With a large F-number, it is difficult to achieve high resolution in deep regions without extending the effective aperture size. We propose a method to extend the available aperture size for SA-called synthetic tracked aperture ultrasound (STRATUS) imaging-by sweeping an ultrasound transducer while tracking its orientation and location. Tracking information of the ultrasound probe is used to synthesize the signals received at different positions. Considering the practical implementation, we estimated the effect of tracking and ultrasound calibration error to the quality of the final beamformed image through simulation. In addition, to experimentally validate this approach, a 6 degree-of-freedom robot arm was used as a mechanical tracker to hold an ultrasound transducer and to apply in-plane lateral translational motion. Results indicate that STRATUS imaging with robotic tracking has the potential to improve ultrasound image quality. PMID:27088108

  6. Integrated medical school ultrasound: development of an ultrasound vertical curriculum

    Bahner, David P.; Eric J Adkins; Hughes, Daralee; Barrie, Michael; Boulger, Creagh T; Royall, Nelson A

    2013-01-01

    Background Physician-performed focused ultrasonography is a rapidly growing field with numerous clinical applications. Focused ultrasound is a clinically useful tool with relevant applications across most specialties. Ultrasound technology has outpaced the education, necessitating an early introduction to the technology within the medical education system. There are many challenges to integrating ultrasound into medical education including identifying appropriately trained faculty, access to ...

  7. AMUM LECTURE: Therapeutic ultrasound

    Crum, Lawrence A.

    2004-01-01

    The use of ultrasound in medicine is now quite commonplace, especially with the recent introduction of small, portable and relatively inexpensive, hand-held diagnostic imaging devices. Moreover, ultrasound has expanded beyond the imaging realm, with methods and applications extending to novel therapeutic and surgical uses. These applications broadly include: tissue ablation, acoustocautery, lipoplasty, site-specific and ultrasound mediated drug activity, extracorporeal lithotripsy, and the enhancement of natural physiological functions such as wound healing and tissue regeneration. A particularly attractive aspect of this technology is that diagnostic and therapeutic systems can be combined to produce totally non-invasive, imageguided therapy. This general lecture will review a number of these exciting new applications of ultrasound and address some of the basic scientific questions and future challenges in developing these methods and technologies for general use in our society. We shall particularly emphasize the use of High Intensity Focused Ultrasound (HIFU) in the treatment of benign and malignant tumors as well as the introduction of acoustic hemostasis, especially in organs which are difficult to treat using conventional medical and surgical techniques.

  8. Children's (Pediatric) Abdominal Ultrasound Imaging

    Full Text Available ... be guided by ultrasound, are used to sample cells from organs for laboratory testing help identify the ... in which needles are used to extract sample cells from an abnormal area for laboratory testing. Ultrasound ...

  9. Children's (Pediatric) Abdominal Ultrasound Imaging

    Full Text Available ... patient. Because ultrasound images are captured in real-time, they can show the structure and movement of ... vomiting in young infants Because ultrasound provides real-time images, images that are renewed continuously, it also ...

  10. Children's (Pediatric) Abdominal Ultrasound Imaging

    Full Text Available ... medicine, ultrasound is used to detect changes in appearance, size or contour of organs, tissues, and vessels or to detect abnormal masses, such as tumors. In an ultrasound examination, a transducer both sends ...

  11. Children's (Pediatric) Abdominal Ultrasound Imaging

    Full Text Available ... top of page What are the benefits vs. risks? Benefits Most ultrasound scanning is noninvasive (no needles ... cord and hip joints in newborns and infants. Risks For standard diagnostic ultrasound , there are no known ...

  12. Ultrasound Diagnostics of Liver Cancer

    Schukina О.Е.

    2014-01-01

    The literature review presents opportunities of the contemporary ultrasound technologies in diagnostics of liver cancer; diagnostic criteria have been determined; the accuracy degree of the ultrasound method in grey-scale and Doppler imaging have been also revealed.

  13. Array tomography: imaging stained arrays.

    Micheva, Kristina D; O'Rourke, Nancy; Busse, Brad; Smith, Stephen J

    2010-11-01

    Array tomography is a volumetric microscopy method based on physical serial sectioning. Ultrathin sections of a plastic-embedded tissue are cut using an ultramicrotome, bonded in an ordered array to a glass coverslip, stained as desired, and imaged. The resulting two-dimensional image tiles can then be reconstructed computationally into three-dimensional volume images for visualization and quantitative analysis. The minimal thickness of individual sections permits high-quality rapid staining and imaging, whereas the array format allows reliable and convenient section handling, staining, and automated imaging. Also, the physical stability of the arrays permits images to be acquired and registered from repeated cycles of staining, imaging, and stain elution, as well as from imaging using multiple modalities (e.g., fluorescence and electron microscopy). Array tomography makes it possible to visualize and quantify previously inaccessible features of tissue structure and molecular architecture. However, careful preparation of the tissue is essential for successful array tomography; these steps can be time-consuming and require some practice to perfect. In this protocol, tissue arrays are imaged using conventional wide-field fluorescence microscopy. Images can be captured manually or, with the appropriate software and hardware, the process can be automated. PMID:21041399

  14. Array tomography: production of arrays.

    Micheva, Kristina D; O'Rourke, Nancy; Busse, Brad; Smith, Stephen J

    2010-11-01

    Array tomography is a volumetric microscopy method based on physical serial sectioning. Ultrathin sections of a plastic-embedded tissue are cut using an ultramicrotome, bonded in an ordered array to a glass coverslip, stained as desired, and imaged. The resulting two-dimensional image tiles can then be reconstructed computationally into three-dimensional volume images for visualization and quantitative analysis. The minimal thickness of individual sections permits high-quality rapid staining and imaging, whereas the array format allows reliable and convenient section handling, staining, and automated imaging. Also, the physical stability of the arrays permits images to be acquired and registered from repeated cycles of staining, imaging, and stain elution, as well as from imaging using multiple modalities (e.g., fluorescence and electron microscopy). Array tomography makes it possible to visualize and quantify previously inaccessible features of tissue structure and molecular architecture. However, careful preparation of the tissue is essential for successful array tomography; these steps can be time consuming and require some practice to perfect. This protocol describes the sectioning of embedded tissues and the mounting of the serial arrays. The procedures require some familiarity with the techniques used for ultramicrotome sectioning for electron microscopy. PMID:21041397

  15. Synthetic Aperture Ultrasound Imaging

    Jensen, Jørgen Arendt; Nikolov, Svetoslav; Gammelmark, Kim Løkke;

    2006-01-01

    The paper describes the use of synthetic aperture (SA) imaging in medical ultrasound. SA imaging is a radical break with today's commercial systems, where the image is acquired sequentially one image line at a time. This puts a strict limit on the frame rate and the possibility of acquiring a...... SA imaging. Due to the complete data set, it is possible to have both dynamic transmit and receive focusing to improve contrast and resolution. It is also possible to improve penetration depth by employing codes during ultrasound transmission. Data sets for vector flow imaging can be acquired using...... short imaging sequences, whereby both the correct velocity magnitude and angle can be estimated. A number of examples of both phantom and in-vivo SA images will be presented measured by the experimental ultrasound scanner RASMUS to demonstrate the many benefits of SA imaging....

  16. Ultrasound cleaning of microfilters

    Hald, Jens; Bjørnø, Irina; Jensen, Leif Bjørnø

    1999-01-01

    The aim of the present work is to develop, design, and manufacture a high-power ultrasound transducer module to be used for preventing the blocking of plastic-based microfilters by organic materials, and possibly to prolong the lifetime of the filters in industry using the cavitation on the surface...... design suitable for cleaning of microfilters without damaging the filter structure. The filter surface was studied using an optical microscope before and after the experiment. When high-power ultrasound (max. 75 W/cm2) was applied to the surface of some microfilters, no visible damage was found, while...... others filters were damaged. The results of the laboratory experiments formed background for the final design of an ultrasound transducer module for use by foodstuff filtration plants. [This work was financed by the EU Project WAMBIO PL96-3257 (FAIR Programme).]...

  17. Focused Ultrasound and Lithotripsy.

    Ikeda, Teiichiro; Yoshizawa, Shin; Koizumi, Norihiro; Mitsuishi, Mamoru; Matsumoto, Yoichiro

    2016-01-01

    Shock wave lithotripsy has generally been a first choice for kidney stone removal. The shock wave lithotripter uses an order of microsecond pulse durations and up to a 100 MPa pressure spike triggered at approximately 0.5-2 Hz to fragment kidney stones through mechanical mechanisms. One important mechanism is cavitation. We proposed an alternative type of lithotripsy method that maximizes cavitation activity to disintegrate kidney stones using high-intensity focused ultrasound (HIFU). Here we outline the method according to the previously published literature (Matsumoto et al., Dynamics of bubble cloud in focused ultrasound. Proceedings of the second international symposium on therapeutic ultrasound, pp 290-299, 2002; Ikeda et al., Ultrasound Med Biol 32:1383-1397, 2006; Yoshizawa et al., Med Biol Eng Comput 47:851-860, 2009; Koizumi et al., A control framework for the non-invasive ultrasound the ragnostic system. Proceedings of 2009 IEEE/RSJ International Conference on Intelligent Robotics and Systems (IROS), pp 4511-4516, 2009; Koizumi et al., IEEE Trans Robot 25:522-538, 2009). Cavitation activity is highly unpredictable; thus, a precise control system is needed. The proposed method comprises three steps of control in kidney stone treatment. The first step is control of localized high pressure fluctuation on the stone. The second step is monitoring of cavitation activity and giving feedback on the optimized ultrasound conditions. The third step is stone tracking and precise ultrasound focusing on the stone. For the high pressure control we designed a two-frequency wave (cavitation control (C-C) waveform); a high frequency ultrasound pulse (1-4 MHz) to create a cavitation cloud, and a low frequency trailing pulse (0.5 MHz) following the high frequency pulse to force the cloud into collapse. High speed photography showed cavitation collapse on a kidney stone and shock wave emission from the cloud. We also conducted in-vitro erosion tests of model and natural

  18. Recent advances in medical ultrasound

    Crum, Lawrence

    2014-03-01

    Ultrasound has become one of the most widely used imaging modalities in medicine; yet, before ultrasound-imaging systems became available, high intensity ultrasound was used as early as the 1950s to ablate regions in the brains of human patients. Recently, a variety of novel applications of ultrasound have been developed that include site-specific and ultrasound-mediated drug delivery, acoustocautery, lipoplasty, histotripsy, tissue regeneration, and bloodless surgery, among many others. This lecture will review several new applications of therapeutic ultrasound and address some of the basic scientific questions and future challenges in developing these methods and technologies for general use in our society. We shall particularly emphasize the use of High Intensity Focused Ultrasound (HIFU) in the treatment of benign and malignant tumors.

  19. Recursive ultrasound imaging

    2000-01-01

    A method and an apparatus for recursive ultrasound imaging is presented. The method uses a Synthetic Transmit Aperture, but unlike previous approaches a new frame is created at every pulse emission. In receive, parallel beam forming is implemented. The beam formed RF data is added to the previously...

  20. Deconvolution of ultrasound images

    Jensen, Jørgen Arendt

    1992-01-01

    Based on physical models, it is indicated that the received pressure field in ultrasound B-mode images can be described by a convolution between a tissue reflection signal and the emitted pressure field. This result is used in a description of current image formation and in formulating a new...

  1. Ultrasound: Infant Hip

    ... ultrasound when they suspect a problem called developmental dysplasia of the hip (DDH) . DDH is a hip deformity that can ... THIS TOPIC X-Ray Exam: Leg Length Developmental Dysplasia of the Hip X-Ray Exam: Hip Contact Us Print Resources ...

  2. General Ultrasound Imaging

    Full Text Available ... that allows the physician to see and evaluate blood flow through arteries and veins in the abdomen, arms, legs, neck and/or brain (in infants and children) or within various body organs such as the liver or kidneys. There are three types of Doppler ultrasound: Color Doppler uses a computer ...

  3. General Ultrasound Imaging

    Full Text Available ... do not use ionizing radiation (as used in x-rays ), thus there is no radiation exposure to the ... tissues that do not show up well on x-ray images. Ultrasound is the preferred imaging modality for ...

  4. Ultrasound of renal transplantation

    Baxter, G.M

    2001-10-01

    The most effective primary treatment of chronic renal failure is renal transplantation. A significant improvement in lifestyle and family life in conjunction with it being an extremely cost-effective procedure has resulted in an intense monitoring and imaging programme to help ensure a successful outcome. Ultrasound, both grey-scale and colour-flow Doppler, are useful monitoring techniques when interpreted in the clinical context, and in the delineation of peri-transplant collections, some of which can be drained under ultrasound guidance. After the early post-operative period it can also be utilized in the diagnosis of chronic vascular complications including transplant artery stenosis and arteriovenous fistula, although it is of limited use in the diagnosis of chronic rejection. This article will discuss the role of ultrasound in all its guises and how its efficacy in both the early transplant period in the monitoring of graft dysfunction and in the detection of the more chronic conditions including transplant artery stenosis and arteriovenous fistulae. A more limited role for ultrasound also exists in the long-term follow-up of patients and to aid the detection of complications including susceptibility to malignancy. Baxter, G.M. (2001)

  5. General Ultrasound Imaging

    Full Text Available ... is commonly called an “echocardiogram” or “echo” for short. Doppler ultrasound images can help the physician to ... not an ideal imaging technique for air-filled bowel or organs obscured by the bowel. In most ...

  6. Tracked ultrasound elastography (TRUE)

    Foroughi, Pezhman

    Medical ultrasound research has experienced a renaissance in the past decade leading to innovations in flow mapping, elasticity and thermal imaging, measurement of optical properties, beamforming, and image enhancement. In this thesis, we focus on ultrasound elastography, an emerging imaging modality with great potential to become a part of several ultrasound diagnostic applications. Elastography images the stiffness of soft tissue by applying a mechanical stimulus and estimating the disturbance created by this stimulus. In freehand elastography, soft tissue is palpated by hand using the ultrasound transducer. The elastography image is generated by comparing the pre- and post-compression images to form a displacement map which is then differentiated to produce the final strain map. To achieve the best result in freehand elastography, the sonographer must compress and decompress the tissue uniformly in a specific direction with adequate compression. This can be a difficult task even for trained users. A small rotational or out-of-plane motion in the collected ultrasound frames can render them unusable for elastography. This has made freehand elastography highly qualitative and user-dependent. We tackle this issue by incorporating the extra information from a position sensor attached to the ultrasound transducer. Our aim is to show that the localization information of ultrasound images may be utilized to improve the quality and reliability of freehand elastography. For this purpose, we have developed a frame selection scheme that finds pairs of images with optimal compression and minimal lateral and out-of-plane displacement. Relying on the localization information, our algorithm merges multiple strain images computed from the selected frame pairs. This method is applicable to both 2D and 3D elastography. Our 3D elastography does not require for the transducer to be held still during the acquisition of each volume. Instead, the sonographer freely palpates the tissue

  7. Synthetic Receive Beamforming and Image Acquisition Capabilities Using an 8 x 128 1.75D Array

    Fernandez, Anna T.; Gammelmark, Kim; Dahl, Jeremy J.;

    2003-01-01

    Ultrasound imaging can be improved with higher order arrays through elevation dynamic focusing in future, higher channel count systems. However, modifications to current system hardware could yield increased imaging depth-of-field with 1.75D arrays (arrays with individually addressable elements...

  8. Ultrasound Imaging Using Diffraction Tomography in a Cylindrical Geometry

    Chambers, D H; Littrup, P

    2002-01-24

    Tomographic images of tissue phantoms and a sample of breast tissue have been produced from an acoustic synthetic array system for frequencies near 500 kHz. The images for sound speed and attenuation show millimeter resolution and demonstrate the feasibility of obtaining high-resolution tomographic images with frequencies that can deeply penetrate tissue. The image reconstruction method is based on the Born approximation to acoustic scattering and is a simplified version of a method previously used by Andre (Andre, et. al., Int. J. Imaging Systems and Technology, Vol 8, No. 1, 1997) for a circular acoustic array system. The images have comparable resolution to conventional ultrasound images at much higher frequencies (3-5 MHz) but with lower speckle noise. This shows the potential of low frequency, deeply penetrating, ultrasound for high-resolution quantitative imaging.

  9. Flat HIFU transducer with a sawtooth-shaped ultrasound radiation face

    Son, Keon-Ho; Cho, Young-Ki; Kim, Dae-Seung; Kim, Myung-Deok; Kang, Kook-Jin

    2013-10-01

    High-intensity focused ultrasound (HIFU) transducers are spherically-curved in order to obtain a high intensity gain of the converged ultrasound energy at the geometrical focus. Ultrasound imaging devices monitor the procedure of HIFU treatment in ultrasound-guided HIFU systems where the image probe is positioned at the apex of the HIFU transducer, which has a spherical surface. However, the remote image probe's location yields a poor image quality compared to that obtained using conventional ultrasound imaging where the image probe is in direct contact with the surface. A phased array HIFU transducer with a new structure is suggested to overcome this limitation. The centers of the array elements are distributed over the flat surface of the transducer. However, the elements are tilted to form a geometrical focus, like a transducer with a spherically-curved surface, to obtain a high focal gain. The cross-section of the ultrasound radiation face of the transducer resembles the teeth of a saw. The acoustic field emitted from this transducer was simulated in order to design and produce the transducer. The simulation was compared with the measured sound field to verify that the transducer was correctly manufactured and designed; subsequently, the acoustic power was measured, and ultrasound images were obtained through the installation of an image probe on the transducer, which confirmed the application of this transducer to HIFU treatment.

  10. Integrated transrectal probe for translational ultrasound-photoacoustic imaging

    Bell, Kevan L.; Harrison, Tyler; Usmani, Nawaid; Zemp, Roger J.

    2016-03-01

    A compact photoacoustic transrectal probe is constructed for improved imaging in brachytherapy treatment. A 192 element 5 MHz linear transducer array is mounted inside a small 3D printed casing along with an array of optical fibers. The device is fed by a pump laser and tunable NIR-optical parametric oscillator with data collected by a Verasonics ultrasound platform. This assembly demonstrates improved imaging of brachytherapy seeds in phantoms with depths up to 5 cm. The tuneable excitation in combination with standard US integration provides adjustable contrast between the brachytherapy seeds, blood filled tubes and background tissue.

  11. Musculoskeletal infections: ultrasound appearances

    Chau, C.L.F. [Department of Radiology, North District Hospital, NTEC, Fanling, NT, Hong Kong (China)]. E-mail: c8681@yahoo.com; Griffith, J.F. [Department of Diagnostic Radiology and Organ Imaging, Prince of Wales Hospital, NTEC, Shatin, NT, Hong Kong (China)

    2005-02-01

    Musculoskeletal infections are commonly encountered in clinical practice. This review will discuss the ultrasound appearances of a variety of musculoskeletal infections such as cellulitis, infective tenosynovitis, pyomyositis, soft-tissue abscesses, septic arthritis, acute and chronic osteomyelitis, and post-operative infection. The peculiar sonographic features of less common musculoskeletal infections, such as necrotizing fasciitis, and rice body formation in atypical mycobacterial tenosynovitis, and bursitis will also be presented.

  12. Prostate Focused Ultrasound Therapy.

    Chapelon, Jean-Yves; Rouvière, Olivier; Crouzet, Sébastien; Gelet, Albert

    2016-01-01

    The tremendous progress in engineering and computing power coupled with ultrasound transducer technology and imaging modalities over the past 20 years have encouraged a revival of clinical interest in ultrasound therapy, mainly in High-Intensity Focused Ultrasound (HIFU). So far, the most extensive results from HIFU obtained in urology involve transrectal prostate ablation, which appears to be an effective therapeutic alternative for patients with malignant prostate tumors. Prostate cancer (PCa) is one of the most frequently diagnosed cancers in men. Several treatment options with different therapeutic approaches exist, including HIFU for localized PCa that has been in use for over 15 years. Since the early 2000s, two systems have been marketed for this application, and other devices are currently in clinical trials. HIFU treatment can be used either alone or in combination with (before- or after-) external beam radiotherapy (EBRT) (before or after HIFU) and can be repeated multiple times. HIFU treatment is performed under real-time monitoring with ultrasound or guided by MRI. Two indications are validated today: Primary care treatment and EBRT failure. The results of HIFU for primary care treatment are similar to standard conformal EBRT, even though no randomized comparative studies have been performed and no 10-year follow up data is yet available for HIFU. Salvage HIFU after EBRT failure is increasing with oncological outcomes, similar to those achieved with surgery but with the advantage of fewer adverse effects. HIFU is an evolving technology perfectly adapted for focal treatment. Thus, HIFU focal therapy is another pathway that must be explored when considering the accuracy and reliability for PCa mapping techniques. HIFU would be particularly suited for such a therapy since it is clear that HIFU outcomes and toxicity are relative to the volume of prostate treated. PMID:26486330

  13. Imaging By Ultrasound

    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 (g...

  14. Ultrasound mediated gene transfection

    Williamson, Rene G.; Apfel, Robert E.; Brandsma, Janet L.

    2002-05-01

    Gene therapy is a promising modality for the treatment of a variety of human diseases both inherited and acquired, such as cystic fibrosis and cancer. The lack of an effective, safe method for the delivery of foreign genes into the cells, a process known as transfection, limits this effort. Ultrasound mediated gene transfection is an attractive method for gene delivery since it is a noninvasive technique, does not introduce any viral particles into the host and can offer very good temporal and spatial control. Previous investigators have shown that sonication increases transfection efficiency with and without ultrasound contrast agents. The mechanism is believed to be via a cavitation process where collapsing bubble nuclei permeabilize the cell membrane leading to increased DNA transfer. The research is focused on the use of pulsed wave high frequency focused ultrasound to transfect DNA into mammalian cells in vitro and in vivo. A better understanding of the mechanism behind the transfection process is also sought. A summary of some in vitro results to date will be presented, which includes the design of a sonication chamber that allows us to model the in vivo case more accurately.

  15. All-optical pulse-echo ultrasound probe for intravascular imaging (Conference Presentation)

    Colchester, Richard J.; Noimark, Sacha; Mosse, Charles A.; Zhang, Edward Z.; Beard, Paul C.; Parkin, Ivan P.; Papakonstantinou, Ioannis; Desjardins, Adrien E.

    2016-02-01

    High frequency ultrasound probes such as intravascular ultrasound (IVUS) and intracardiac echocardiography (ICE) catheters can be invaluable for guiding minimally invasive medical procedures in cardiology such as coronary stent placement and ablation. With current-generation ultrasound probes, ultrasound is generated and received electrically. The complexities involved with fabricating these electrical probes can result in high costs that limit their clinical applicability. Additionally, it can be challenging to achieve wide transmission bandwidths and adequate wideband reception sensitivity with small piezoelectric elements. Optical methods for transmitting and receiving ultrasound are emerging as alternatives to their electrical counterparts. They offer several distinguishing advantages, including the potential to generate and detect the broadband ultrasound fields (tens of MHz) required for high resolution imaging. In this study, we developed a miniature, side-looking, pulse-echo ultrasound probe for intravascular imaging, with fibre-optic transmission and reception. The axial resolution was better than 70 microns, and the imaging depth in tissue was greater than 1 cm. Ultrasound transmission was performed by photoacoustic excitation of a carbon nanotube/polydimethylsiloxane composite material; ultrasound reception, with a fibre-optic Fabry-Perot cavity. Ex vivo tissue studies, which included healthy swine tissue and diseased human tissue, demonstrated the strong potential of this technique. To our knowledge, this is the first study to achieve an all-optical pulse-echo ultrasound probe for intravascular imaging. The potential for performing all-optical B-mode imaging (2D and 3D) with virtual arrays of transmit/receive elements, and hybrid imaging with pulse-echo ultrasound and photoacoustic sensing are discussed.

  16. Robotic inspection of fiber reinforced composites using phased array UT

    Stetson, Jeffrey T.; De Odorico, Walter

    2014-02-01

    Ultrasound is the current NDE method of choice to inspect large fiber reinforced airframe structures. Over the last 15 years Cartesian based scanning machines using conventional ultrasound techniques have been employed by all airframe OEMs and their top tier suppliers to perform these inspections. Technical advances in both computing power and commercially available, multi-axis robots now facilitate a new generation of scanning machines. These machines use multiple end effector tools taking full advantage of phased array ultrasound technologies yielding substantial improvements in inspection quality and productivity. This paper outlines the general architecture for these new robotic scanning systems as well as details the variety of ultrasonic techniques available for use with them including advances such as wide area phased array scanning and sound field adaptation for non-flat, non-parallel surfaces.

  17. Crystallization of glycine with ultrasound

    Louhi-Kultanen, Marjatta; Karjalainen, Milja; Rantanen, Jukka;

    2006-01-01

    Sonocrystallization has proved to be an efficient tool to influence the external appearance and structure of a crystalline product obtained by various crystallization methods. The present work focuses on high intensity sonocrystallization of glycine by varying amplitude of ultrasound with an...... ultrasound frequency of 20kHz at two temperature ranges 40-50 and 20-30 degrees C in a jacketed 250-ml cooling crystallizer equipped with a stirrer. The polymorph composition of the obtained crystals was analyzed with a temperature variable X-ray powder diffractometer (XRPD). XRPD results showed that...... ultrasound power. This study also showed, the higher the ultrasound amplitude the smaller the crystals obtained....

  18. Physics of Ultrasound. Chapter 12

    Ultrasound is the most commonly used diagnostic imaging modality, accounting for approximately 25% of all imaging examinations performed worldwide at the beginning of the 21st century. The success of ultrasound may be attributed to a number of attractive characteristics, including the relatively low cost and portability of an ultrasound scanner, the non-ionizing nature of ultrasound waves, the ability to produce real time images of blood flow and moving structures such as the beating heart, and the intrinsic contrast among soft tissue structures that is achieved without the need for an injected contrast agent. The latter characteristic enables ultrasound to be used for a wide range of medical applications, which historically have primarily included cardiac and vascular imaging, imaging of the abdominal organs and, most famously, in utero imaging of the developing fetus. Ongoing technological improvements continue to expand the use of ultrasound for many applications, including cancer imaging, musculoskeletal imaging, ophthalmology and others. The term ultrasound refers specifically to acoustic waves at frequencies greater than the maximum frequency audible to humans, which is nominally 20 kHz. Diagnostic imaging is generally performed using ultrasound in the frequency range of 2–15 MHz. The choice of frequency is dictated by a trade off between spatial resolution and penetration depth, since higher frequency waves can be focused more tightly but are attenuated more rapidly by tissue. The information contained in an ultrasonic image is influenced by the physical processes underlying propagation, reflection and attenuation of ultrasound waves in tissue

  19. Ultrasound diagnostics of thyroid diseases

    Kharchenko, Vladimir P. [Russian Radiology Research Center, Moscow (Russian Federation); Kotlyarov, Peter M. [Russian Center of Roentgenradiology, Moscow (Russian Federation); Mogutov, Mikhail S.; Sencha, Alexander N.; Patrunov, Yury N.; Belyaev, Denis V. [Yaroslavl Railway Clinic (Russian Federation); Alexandrov, Yury K. [State Medical Academy, Yaroslavl (Russian Federation)

    2010-07-01

    This book is based on the authors' extensive practical experience in the use of modern ultrasound, and other radiological methods, in the diagnosis of thyroid diseases. The authors have analyzed more than 100,000 ultrasound examinations performed between 1995 and 2008 in patients with thyroid and parathyroid disease, as well as many thousands of diagnostic and therapeutic ultrasound-guided minimally invasive procedures. The opening chapters include discussion of current ultrasound techniques, pitfalls, and the specifics of ultrasound examination of the thyroid in children. Detailed attention is then devoted to findings in the normal thyroid and in the presence of diffuse and focal changes. Further chapters focus on such topics as ultrasound examination after thyroid surgery and ultrasound diagnosis of parathyroid disease, recurrent goiter, and neck masses. Ultrasound-guided minimally invasive techniques, such as fine-needle aspiration biopsy, percutaneous laser ablation, and ethanol and glucocorticoid injections, are considered in depth. This up-to-date and richly illustrated book will interest and assist specialists in ultrasound diagnostics, radiologists, endocrinologists, and neck surgeons. (orig.)

  20. Ultrasound diagnostics of thyroid diseases

    This book is based on the authors' extensive practical experience in the use of modern ultrasound, and other radiological methods, in the diagnosis of thyroid diseases. The authors have analyzed more than 100,000 ultrasound examinations performed between 1995 and 2008 in patients with thyroid and parathyroid disease, as well as many thousands of diagnostic and therapeutic ultrasound-guided minimally invasive procedures. The opening chapters include discussion of current ultrasound techniques, pitfalls, and the specifics of ultrasound examination of the thyroid in children. Detailed attention is then devoted to findings in the normal thyroid and in the presence of diffuse and focal changes. Further chapters focus on such topics as ultrasound examination after thyroid surgery and ultrasound diagnosis of parathyroid disease, recurrent goiter, and neck masses. Ultrasound-guided minimally invasive techniques, such as fine-needle aspiration biopsy, percutaneous laser ablation, and ethanol and glucocorticoid injections, are considered in depth. This up-to-date and richly illustrated book will interest and assist specialists in ultrasound diagnostics, radiologists, endocrinologists, and neck surgeons. (orig.)

  1. Developing an emergency ultrasound app

    Foss, K. T.; Subhi, Y.; Aagaard, R.;

    2015-01-01

    Focused emergency ultrasound is rapidly evolving as a clinical skill for bedside examination by physicians at all levels of education. Ultrasound is highly operator-dependent and relevant training is essential to ensure appropriate use. When supplementing hands-on focused ultrasound courses, e-le......-learning can increase the learning effect. We developed an emergency ultrasound app to enable onsite e-learning for trainees. In this paper, we share our experiences in the development of this app and present the final product....

  2. Screen printed thick film based pMUT arrays

    Hedegaard, Tobias; Pedersen, T; Thomsen, Erik Vilain;

    2008-01-01

    This article reports on the fabrication and characterization of lambda-pitched piezoelectric micromachined ultrasound transducer (pMUT) arrays fabricated using a unique process combining conventional silicon technology and low cost screen printing of thick film PZT. The pMUTs are designed as 8...

  3. General Ultrasound Imaging

    Full Text Available ... Color Doppler uses a computer to convert Doppler measurements into an array of colors to show the ... in some situations. Spectral Doppler displays blood flow measurements graphically, in terms of the distance traveled per ...

  4. General Ultrasound Imaging

    Full Text Available ... into an array of colors to show the speed and direction of blood flow through a blood ... sometimes seen in infections With knowledge about the speed and volume of blood flow gained from a ...

  5. Spatial filters for focusing ultrasound images

    Jensen, Jørgen Arendt; Gori, Paola

    2001-01-01

    . A new method for making spatial matched filter focusing of RF ultrasound data is proposed based on the spatial impulse response description of the imaging. The response from a scatterer at any given point in space relative to the transducer can be calculated, and this gives the spatial matched filter...... for beamforming the received RF signals from the individual transducer elements. The matched filter is applied on RF signals from individual transducer elements, thus properly taking into account the spatial spread of the received signal. The method can be applied to any transducer and can also be used...... of the autocovariance function of the image shows a -6 dB width reduction by a factor of 3.3 at 20 mm and by a factor of 1.8 at 30 mm. Other simulations use a 64 elements, 3 MHz, linear array. Different receiving conditions are compared and this shows that the effect of the filter is progressively lower...

  6. Small part ultrasound in childhood and adolescence

    Wunsch, R., E-mail: R.Wunsch@kinderklinik-datteln.de [Department of Pediatric Radiology, Vestic Children' s Hospital Datteln, University of Witten/Herdecke, Dr.-Friedrich-Steiner-Strasse 5, D-45711 Datteln (Germany); Rohden, L. von, E-mail: l.vonrohden@gmx.de [Department of Pediatric Radiology, Otto-von-Guericke-University Magdeburg, Klinik f. Radiologie und Nuklearmedizin – Kinderradiologie, Leipziger Straße 44, D-39120 Magdeburg (Germany); Cleaveland, R. [Department of Pediatric Radiology, Vestic Children' s Hospital Datteln, University of Witten/Herdecke, Dr.-Friedrich-Steiner-Strasse 5, D-45711 Datteln (Germany); Aumann, V., E-mail: volker.aumann@med.ovgu.de [Department of Pediatric Haematology and Oncology, Otto-von-Guericke-University Magdeburg, Universitätskinderklinik (H 10), Pädiatrische Hämatologie und Onkologie, Leipziger Straße 44, D-39120 Magdeburg (Germany)

    2014-09-15

    Small-part sonography refers to the display of small, near-surface structures using high-frequency linear array transducers. Traditional applications for small part ultrasound imaging include visualization and differential diagnostic evaluation in unclear superficial bodily structures with solid, liquid and mixed texture, as well as similar structures in nearly superficial organs such as the thyroid glands and the testes. Furthermore indications in the head and neck regions are the assessment of the outer CSF spaces in infants, the sonography of the orbit, the sonography of the walls of the large neck vessels, the visualization of superficially situated lymph nodes and neoplasms. Clinical evidence concludes that sonography, having of all imaging modalities the highest spatial resolution in the millimeter- and micrometer range (100–1000 μm), can be considered the best suited technique for examining superficial pathological formations and near-surface organs. In addition, it delivers important information about characteristic, often pathognomonic tissue architecture in pathological processes.

  7. Small part ultrasound in childhood and adolescence

    Small-part sonography refers to the display of small, near-surface structures using high-frequency linear array transducers. Traditional applications for small part ultrasound imaging include visualization and differential diagnostic evaluation in unclear superficial bodily structures with solid, liquid and mixed texture, as well as similar structures in nearly superficial organs such as the thyroid glands and the testes. Furthermore indications in the head and neck regions are the assessment of the outer CSF spaces in infants, the sonography of the orbit, the sonography of the walls of the large neck vessels, the visualization of superficially situated lymph nodes and neoplasms. Clinical evidence concludes that sonography, having of all imaging modalities the highest spatial resolution in the millimeter- and micrometer range (100–1000 μm), can be considered the best suited technique for examining superficial pathological formations and near-surface organs. In addition, it delivers important information about characteristic, often pathognomonic tissue architecture in pathological processes

  8. Children's (Pediatric) Abdominal Ultrasound Imaging

    ... page How is the procedure performed? For most ultrasound exams, you will be positioned lying face-up on an examination table that can be ... either side or on occasion placed in a face down position to improve the quality ... (ultrasound technologist) or radiologist then places the transducer on ...

  9. Children's (Pediatric) Abdominal Ultrasound Imaging

    Full Text Available ... page How is the procedure performed? For most ultrasound exams, you will be positioned lying face-up on an examination table that can be ... either side or on occasion placed in a face down position to improve the quality ... (ultrasound technologist) or radiologist then places the transducer on ...

  10. Silicon photonic micro-ring resonators to sense strain and ultrasound

    Westerveld, W. J.

    2014-01-01

    We demonstrated that photonic micro-ring resonators can be used in micro-machined ultrasound microphones. This might cause a breakthrough in array transducers for ultrasonography; first because optical multiplexing allows array interrogation via one optical fiber and second because the silicon-on-insulator technology allows cost-effective fabrication. To understand this microphone, all of its components were studied: fundamental theory of the photonic resonators, experimental characteristics ...

  11. Cumulative phase delay imaging - A new contrast enhanced ultrasound modality

    Demi, Libertario, E-mail: l.demi@tue.nl; Sloun, Ruud J. G. van; Mischi, Massimo [Lab. of Biomedical Diagnostics, Dept. of Electrical Eng., Eindhoven University of Technology (Netherlands); Wijkstra, Hessel [Lab. of Biomedical Diagnostics, Dept. of Electrical Eng., Eindhoven University of Technology (Netherlands); Academic Medical Center, Urology Dept., University of Amsterdam (Netherlands)

    2015-10-28

    Recently, a new acoustic marker for ultrasound contrast agents (UCAs) has been introduced. A cumulative phase delay (CPD) between the second harmonic and fundamental pressure wave field components is in fact observable for ultrasound propagating through UCAs. This phenomenon is absent in the case of tissue nonlinearity and is dependent on insonating pressure and frequency, UCA concentration, and propagation path length through UCAs. In this paper, ultrasound images based on this marker are presented. The ULA-OP research platform, in combination with a LA332 linear array probe (Esaote, Firenze Italy), were used to image a gelatin phantom containing a PVC plate (used as a reflector) and a cylindrical cavity measuring 7 mm in diameter (placed in between the observation point and the PVC plate). The cavity contained a 240 µL/L SonoVueO{sup ®} UCA concentration. Two insonating frequencies (3 MHz and 2.5 MHz) were used to scan the gelatine phantom. A mechanical index MI = 0.07, measured in water at the cavity location with a HGL-0400 hydrophone (Onda, Sunnyvale, CA), was utilized. Processing the ultrasound signals backscattered from the plate, ultrasound images were generated in a tomographic fashion using the filtered back-projection method. As already observed in previous studies, significantly higher CPD values are measured when imaging at a frequency of 2.5 MHz, as compared to imaging at 3 MHz. In conclusion, these results confirm the applicability of the discussed CPD as a marker for contrast imaging. Comparison with standard contrast-enhanced ultrasound imaging modalities will be the focus of future work.

  12. Cumulative phase delay imaging - A new contrast enhanced ultrasound modality

    Recently, a new acoustic marker for ultrasound contrast agents (UCAs) has been introduced. A cumulative phase delay (CPD) between the second harmonic and fundamental pressure wave field components is in fact observable for ultrasound propagating through UCAs. This phenomenon is absent in the case of tissue nonlinearity and is dependent on insonating pressure and frequency, UCA concentration, and propagation path length through UCAs. In this paper, ultrasound images based on this marker are presented. The ULA-OP research platform, in combination with a LA332 linear array probe (Esaote, Firenze Italy), were used to image a gelatin phantom containing a PVC plate (used as a reflector) and a cylindrical cavity measuring 7 mm in diameter (placed in between the observation point and the PVC plate). The cavity contained a 240 µL/L SonoVueO® UCA concentration. Two insonating frequencies (3 MHz and 2.5 MHz) were used to scan the gelatine phantom. A mechanical index MI = 0.07, measured in water at the cavity location with a HGL-0400 hydrophone (Onda, Sunnyvale, CA), was utilized. Processing the ultrasound signals backscattered from the plate, ultrasound images were generated in a tomographic fashion using the filtered back-projection method. As already observed in previous studies, significantly higher CPD values are measured when imaging at a frequency of 2.5 MHz, as compared to imaging at 3 MHz. In conclusion, these results confirm the applicability of the discussed CPD as a marker for contrast imaging. Comparison with standard contrast-enhanced ultrasound imaging modalities will be the focus of future work

  13. Temperature estimation with ultrasound

    Daniels, Matthew

    Hepatocelluar carcinoma is the fastest growing type of cancer in the United States. In addition, the survival rate after one year is approximately zero without treatment. In many instances, patients with hepatocelluar carcinoma may not be suitable candidates for the primary treatment options, i.e. surgical resection or liver transplantation. This has led to the development of minimally invasive therapies focused on destroying hepatocelluar by thermal or chemical methods. The focus of this dissertation is on the development of ultrasound-based image-guided monitoring options for minimally invasive therapies such as radiofrequency ablation. Ultrasound-based temperature imaging relies on relating the gradient of locally estimated tissue displacements to a temperature change. First, a realistic Finite Element Analysis/ultrasound simulation of ablation was developed. This allowed evaluation of the ability of ultrasound-based temperature estimation algorithms to track temperatures for three different ablation scenarios in the liver. It was found that 2-Dimensional block matching and a 6 second time step was able to accurately track the temperature over a 12 minute ablation procedure. Next, a tissue-mimicking phantom was constructed to determine the accuracy of the temperature estimation method by comparing estimated temperatures to that measured using invasive fiber-optic temperature probes. The 2-Dimensional block matching was able to track the temperature accurately over the entire 8 minute heating procedure in the tissue-mimicking phantom. Finally, two separate in-vivo experiments were performed. The first experiment examined the ability of our algorithm to track frame-to-frame displacements when external motion due to respiration and the cardiac cycle were considered. It was determined that a frame rate between 13 frames per second and 33 frames per second was sufficient to track frame-to-frame displacements between respiratory cycles. The second experiment examined

  14. Ultrasound focusing images in superlattices

    Narita, Michiko; Tanaka, Yukihiro; Tamura, Shin-ichiro

    2002-03-01

    We study theoretically ultrasound focusing in periodic multilayered structures, or superlattices, by solving the wave equation with the Green function method and calculating the transmitted ultrasound amplitude images of both the longitudinal and transverse modes. The constituent layers assumed are elastically isotropic but the periodically stacked structure is anisotropic. Thus anisotropy of ultrasound propagation is predicted even at low frequencies and it is enhanced significantly at higher frequencies due to the zone-folding effect of acoustic dispersion relations. An additional effect studied is the interference of ultrasound (known as the internal diffraction), which can be recognized when the propagation distance is comparable to the ultrasound wavelength. Numerical examples are developed for millimetre-scale Al/polymer multilayers used recently for imaging experiment with surface acoustic waves.

  15. Diagnostic Ultrasound in Colorectal Cancer

    Rafaelsen, Søren Rafael

    2014-01-01

    in the liver metastases. In addition, we prospectively compared contrast-enhanced ultrasound with CT scan in the detection of liver metastases.Results By transrectal ultrasound of polyps using the new AWS technique, a sensitivity of 96% and a specificity of 88% was found for cancer, whereas digital exploration...... to neoadjuvant chemoradiation of advanced rectal cancer.IOUS is a safe method with a significantly higher sensitivity in the detection of liver metastases than preoperative ultrasound and surgical palpation. Patients with liver metastases, which harboured power Doppler signal centrally, more often had advanced...... of rectal cancer, especially in early tumours. Screening for colorectal cancer will give rise to the detection of a number of early tumours. Contrast-enhanced liver ultrasound and intraoperative ultrasound has additional space in the detection of liver metastases from colorectal cancer....

  16. Role of endoscopic ultrasound in diagnosis and therapy of pancreatic adenocarcinoma

    Joseph Boujaoude

    2007-01-01

    Since its advent more than 20 years ago, endoscopic ultrasound (EUS) has undergone evolution from an experimental to a diagnostic instrument and is now established as a therapeutic tool for endoscopists.Endoscopic ultrasound cannot accurately distinguish benign from malignant changes in the primary lesion or lymph node on imaging alone. With the introduction of the curved linear array echoendoscope in the 1990s,the indications for EUS have expanded. The curved linear array echoendoscope enables the visualization of a needle as it exits from the biopsy channel in the same plane of ultrasound imaging in real time. This allows the endoscopist to perform a whole range of interventional applications ranging from fine needle aspiration (FNA) of lesions surrounding the gastrointestinal tract to celiac plexus block and drainage of pancreatic pseudocyst. This article reviews the current role of EUS and EUS-FNA in diagnosis, staging and interventional application of solid pancreatic cancer.

  17. Physiotherapy ultrasound calibrations

    Calibration of physiotherapy ultrasound equipment has long been a problem. Numerous surveys around the world over the past 20 years have all found that only a low percentage of the units tested had an output within 30% of that indicatd. In New Zealand, a survey carried out by the NRL in 1985 found that only 24% had an output, at the maximum setting, within + or - 20% of that indicated. The present performance Standard for new equipment (NZS 3200.2.5:1992) requires that the measured output should not deviate from that indicated by more than + or - 30 %. This may be tightened to + or - 20% in the next few years. Any calibration is only as good as the calibration equipment. Some force balances can be tested with small weights to simulate the force exerted by an ultrasound beam, but with others this is not possible. For such balances, testing may only be feasible with a calibrated source which could be used like a transfer standard. (author). 4 refs., 3 figs

  18. Aesthetic ultrasound therapy

    Barthe, Peter G.; Slayton, Michael H.

    2012-10-01

    Ultrasound provides key benefits in aesthetic surgery compared to laser and RF based energy sources. We present results of research, development, pre-clinical and clinical studies, regulatory clearance and commercialization of a revolutionary non-invasive aesthetic ultrasound imaging and therapy system. Clinical applications for this platform include non-invasive face-lifts, brow-lifts, and neck-lifts achieved through fractionated treatment of the superficial musculoaponeurotic system (SMAS) and subcutaneous tissue. Treatment consists of placing a grid of micro-coagulative lesions on the order of 1 mm3 at depths in skin of 1 to 6 mm, source energy levels of 0.1 to 3 J, and spacing on the order of 1.5 mm, from 4 to 10 MHz dual-mode image/treat transducers. System details are described, as well as a regulatory pathway consisting of acoustic and bioheat simulations, source characterization (hydrophone, radiation force, and Schlieren), pre-clinical studies (porcine skin ex vivo, in vivo, and human cadaver), human safety studies (treat and resect) and efficacy trials which culminated in FDA clearance (2009) under a new device classification and world-wide usage. Clinical before and after photographs are presented which validate the clinical approach.

  19. The Edinburgh Pipe Phantom: characterising ultrasound scanners beyond 50 MHz

    Moran, C M [Medical Physics, University of Edinburgh, Edinburgh, EH16 4TJ (United Kingdom); Ellis, W; Janeczko, A; Pye, S D [Medical Physics Department, NHS Lothian University Hospitals Division, Royal Infirmary, Edinburgh EH16 4SA (United Kingdom); Bell, D, E-mail: carmel.moran@ed.ac.uk [Precision Acoustics Ltd, Hampton Farm Business Park, Dorset, DT2 8QH (United Kingdom)

    2011-02-01

    The ability to measure the imaging performance of pre-clinical and clinical ultrasound scanners is important but difficult to achieve objectively. The Edinburgh Pipe Phantom was originally developed to assess the technical performance of clinical scanners up to 15MHz. It comprises a series of anechoic cylinders with diameters 0.4 - 8mm embedded in agar-based tissue mimic. This design enables measurement of the characteristics (Resolution Integral R, Depth of Field L{sub R}, Characteristic Resolution D{sub R}) of grey-scale images with transducer centre frequencies from about 2.5 to 15MHz. We describe further development of the Edinburgh Pipe Phantom as a tool for characterising ultrasound scanners with centre frequencies up to at least 50MHz. This was achieved by moulding a series of anechoic pipe structures (diameters 0.045 - 1.5mm) into a block of agar-based tissue mimic. We report measurements of R, L{sub R} and D{sub R} for a series of 10 transducers (5 single element and 5 array transducers) designed for pre-clinical scanning, with centre frequencies in the range 15-55 MHz. Values of R ranged from 18-72 for single element transducers and 49-58 for linear array transducers. In conclusion, the pre-clinical pipe phantom was able to successfully determine the imaging characteristics of ultrasound probes up to 55MHz.

  20. New technique for fabrication of high frequency piezoelectric Micromachined Ultrasound Transducers

    Pedersen, T; Thomsen, Erik Vilain; Zawada, T;

    2008-01-01

    A novel technique for fabrication of linear arrays of high frequency piezoelectric Micromachined Ultrasound Transducers (pMUT) on silicon substrates is presented. Piezoelectric elements are formed by deposition of PZT ((PbZrxTi1-x)O3) into etched features of the silicon substrate...

  1. Asynchronous compressed beamformer for portable diagnostic ultrasound systems.

    Zhou, Jun; Hoyos, Sebastian; Sadler, Brian

    2014-11-01

    State-of-the-art portable ultrasound imaging systems employ a small transducer array and a low carrier frequency to fit stringent constraints on power and form factor, and this tends to compromise the ultrasound imaging quality. In this paper, we present a low-complexity low-power asynchronous compressed beamformer (ACB) for portable diagnostic ultrasound. The proposed ACB integrates asynchronous sampling and compressive sensing (CS), and is capable of reducing data conversion power and handling a large data volume at the mixed-signal interface. A high-rate continuoustime ternary encoding (CT-TE) scheme eliminates the need for interpolation filters and coordinate rotation digital computer (CORDIC) units typically used in a conventional architecture. A split-projection least squares (SPLS) signal reconstruction algorithm is applied that replaces high-cost nonlinear signal recovery with a series of low-complexity and independent linear problems. Experiments with measured ultrasound data demonstrate the proposed ACB architecture, and the SPLS reconstruction algorithm achieves 9-fold data compression compared with Nyquist sampling. PMID:25389158

  2. Molecular Endoscopic Ultrasound for Diagnosis of Pancreatic Cancer

    Endoscopic ultrasound-guided fine needle aspiration-biopsy is a safe and effective technique in diagnosing and staging of pancreatic ductal adenocarcinoma. However its predictive negative value does not exceed 50% to 60%. Unfortunately, the majority of pancreatic cancer patients have a metastatic and/or a locally advanced disease (i.e., not eligible for curative resection) which explains the limited access to pancreatic tissue specimens. Endoscopic ultrasound-guided fine needle aspiration-biopsy is the most widely used approach for cytological and histological material sampling in these situations used in up to two thirds of patients with pancreatic cancer. Based on this unique material, we and others developed strategies to improve the differential diagnosis between carcinoma and inflammatory pancreatic lesions by analysis of KRAS oncogene mutation, microRNA expression and methylation, as well as mRNA expression using both qRT-PCR and Low Density Array Taqman analysis. Indeed, differentiating pancreatic cancer from pseudotumoral chronic pancreatitis remains very difficult in current clinical practice, and endoscopic ultrasound-guided fine needle aspiration-biopsy analysis proved to be very helpful. In this review, we will compile the clinical and molecular advantages of using endoscopic ultrasound-guided fine needle aspiration-biopsy in managing pancreatic cancer

  3. Molecular Endoscopic Ultrasound for Diagnosis of Pancreatic Cancer

    Pierre Cordelier

    2011-02-01

    Full Text Available Endoscopic ultrasound-guided fine needle aspiration-biopsy is a safe and effective technique in diagnosing and staging of pancreatic ductal adenocarcinoma. However its predictive negative value does not exceed 50% to 60%. Unfortunately, the majority of pancreatic cancer patients have a metastatic and/or a locally advanced disease (i.e., not eligible for curative resection which explains the limited access to pancreatic tissue specimens. Endoscopic ultrasound-guided fine needle aspiration-biopsy is the most widely used approach for cytological and histological material sampling in these situations used in up to two thirds of patients with pancreatic cancer. Based on this unique material, we and others developed strategies to improve the differential diagnosis between carcinoma and inflammatory pancreatic lesions by analysis of KRAS oncogene mutation, microRNA expression and methylation, as well as mRNA expression using both qRT-PCR and Low Density Array Taqman analysis. Indeed, differentiating pancreatic cancer from pseudotumoral chronic pancreatitis remains very difficult in current clinical practice, and endoscopic ultrasound-guided fine needle aspiration-biopsy analysis proved to be very helpful. In this review, we will compile the clinical and molecular advantages of using endoscopic ultrasound-guided fine needle aspiration-biopsy in managing pancreatic cancer.

  4. Molecular Endoscopic Ultrasound for Diagnosis of Pancreatic Cancer

    Bournet, Barbara [Department of Gastroenterology, University Hospital Center Rangueil, 1 avenue Jean Poulhès, TSA 50032, 31059 Toulouse Cedex 9 (France); INSERM U1037, University Hospital Center Rangueil, Toulouse (France); Pointreau, Adeline; Delpu, Yannick; Selves, Janick; Torrisani, Jerome [INSERM U1037, University Hospital Center Rangueil, Toulouse (France); Buscail, Louis, E-mail: buscail.l@chu-toulouse.fr [Department of Gastroenterology, University Hospital Center Rangueil, 1 avenue Jean Poulhès, TSA 50032, 31059 Toulouse Cedex 9 (France); INSERM U1037, University Hospital Center Rangueil, Toulouse (France); Cordelier, Pierre [INSERM U1037, University Hospital Center Rangueil, Toulouse (France)

    2011-02-24

    Endoscopic ultrasound-guided fine needle aspiration-biopsy is a safe and effective technique in diagnosing and staging of pancreatic ductal adenocarcinoma. However its predictive negative value does not exceed 50% to 60%. Unfortunately, the majority of pancreatic cancer patients have a metastatic and/or a locally advanced disease (i.e., not eligible for curative resection) which explains the limited access to pancreatic tissue specimens. Endoscopic ultrasound-guided fine needle aspiration-biopsy is the most widely used approach for cytological and histological material sampling in these situations used in up to two thirds of patients with pancreatic cancer. Based on this unique material, we and others developed strategies to improve the differential diagnosis between carcinoma and inflammatory pancreatic lesions by analysis of KRAS oncogene mutation, microRNA expression and methylation, as well as mRNA expression using both qRT-PCR and Low Density Array Taqman analysis. Indeed, differentiating pancreatic cancer from pseudotumoral chronic pancreatitis remains very difficult in current clinical practice, and endoscopic ultrasound-guided fine needle aspiration-biopsy analysis proved to be very helpful. In this review, we will compile the clinical and molecular advantages of using endoscopic ultrasound-guided fine needle aspiration-biopsy in managing pancreatic cancer.

  5. Ultrasound effects on the degradation kinetics, structure and rheological properties of apple pectin.

    Zhang, Lifen; Ye, Xinqian; Ding, Tian; Sun, Xiaoyang; Xu, Yuting; Liu, Donghong

    2013-01-01

    The effects of ultrasound on the molecular weight of apple pectin were investigated. The structure and rheological properties of the degradation products were also tentatively identified by High Performance Liquid Chromatography-Photodiode Array Detector (HPLC-PAD), Infrared spectroscopy (IR), Nuclear Magnetic Resonance spectroscopy (NMR) and Rheometer. The results indicated that the weight-average molecular weight of apple pectin decreased obviously after ultrasound treatment. The molecular weight of degradation products had a uniform and narrow distribution. Ultrasound intensity and temperature play an important role in the degradation reaction. Degradation kinetics model of apple pectin fitted to 1/M(t) - 1/M(0) = kt from 5 to 45 °C. The degree of methylation of apple pectin reduced according to IR analysis when ultrasound was applied. Ultrasound treatment could not alter the primary structure of apple pectin according to the results determined by HPLC, IR and NMR. Meanwhile, the viscosity of apple pectin was 10(3) times as large as that of ultrasound-treated apple pectin. The ultrasound-treated apple pectin showed predominantly viscous responses (G' pectin. PMID:22982008

  6. Basics of biomedical ultrasound for engineers

    Azhari, Haim

    2010-01-01

    "Basics of Biomedical Ultrasound for Engineers is a structured textbook for university engineering courses in biomedical ultrasound and for researchers in the field. This book offers a tool for building a solid understanding of biomedical ultrasound, and leads the novice through the field in a step-by-step manner. The book begins with the most basic definitions of waves, proceeds to ultrasounds in fluids, and then delves into solid ultrasounds, the most complicated kind of ultrasound. It encompasses a wide range of topics within biomedical ultrasound, from conceptual definitions of waves to the intricacies of focusing devices, transducers, and acoustic fields"--Provided by publisher.

  7. The use of two-photon microscopy to study the biological effects of focused ultrasound on the brain

    Burgess, Alison; Cho, Eunice E.; Shaffaf, Leila; Nhan, Tam; Poon, Charissa; Hynynen, Kullervo

    2012-03-01

    Focused ultrasound (FUS) has been used to successfully disrupt the blood-brain barrier (BBB), aiding in the delivery of therapeutic agents to the brain and leading to improvements in disease pathology. Although significant progress has been made in the development of FUS technology, there is still a lack of understanding of the biophysical mechanisms of the BBB disruption and the microscopic effects of this disruption on brain cells. In this study, we combine a custom built ultrasound transducer with two-photon microscopy to conduct real time monitoring of BBB disruption in vivo. We have manufactured and tested a single element piezoelectric transducer with frequencies ranging from 1.15 to 1.30 MHz. Sonications were performed using 0.07-0.25 MPa estimated in situ pressure, 10 ms pulses, 1 Hz pulse repetition frequency for a total duration of 120 s in the presence of microbubbles. BBB disruption was observed through a cranial window created in the rat skull after intravenous injection of dextran conjugated- Texas Red (MW: 10,000 - 70,000 Da). Using this experimental setup, we have observed and characterized 3 different leakage patterns following BBB disruption. Our results indicate that varying the acoustic power leading to in situ pressure changes, may allow us to control the mechanism of BBB disruption. Furthermore, we have labelled astrocytes in vivo in order to visualize the effects of FUS on this cell population. Combination of our custom transducers with two-photon microscopy will allow significant advancement in allow significant advancement in the understanding of the mechanisms and cellular effects of FUS-induced BBB disruption.

  8. Droplets, Bubbles and Ultrasound Interactions.

    Shpak, Oleksandr; Verweij, Martin; de Jong, Nico; Versluis, Michel

    2016-01-01

    The interaction of droplets and bubbles with ultrasound has been studied extensively in the last 25 years. Microbubbles are broadly used in diagnostic and therapeutic medical applications, for instance, as ultrasound contrast agents. They have a similar size as red blood cells, and thus are able to circulate within blood vessels. Perfluorocarbon liquid droplets can be a potential new generation of microbubble agents as ultrasound can trigger their conversion into gas bubbles. Prior to activation, they are at least five times smaller in diameter than the resulting bubbles. Together with the violent nature of the phase-transition, the droplets can be used for local drug delivery, embolotherapy, HIFU enhancement and tumor imaging. Here we explain the basics of bubble dynamics, described by the Rayleigh-Plesset equation, bubble resonance frequency, damping and quality factor. We show the elegant calculation of the above characteristics for the case of small amplitude oscillations by linearizing the equations. The effect and importance of a bubble coating and effective surface tension are also discussed. We give the main characteristics of the power spectrum of bubble oscillations. Preceding bubble dynamics, ultrasound propagation is introduced. We explain the speed of sound, nonlinearity and attenuation terms. We examine bubble ultrasound scattering and how it depends on the wave-shape of the incident wave. Finally, we introduce droplet interaction with ultrasound. We elucidate the ultrasound-focusing concept within a droplets sphere, droplet shaking due to media compressibility and droplet phase-conversion dynamics. PMID:26486337

  9. Ultrasound call detection in capybara

    Selene S.C. Nogueira

    2012-07-01

    Full Text Available The vocal repertoire of some animal species has been considered a non-invasive tool to predict distress reactivity. In rats ultrasound emissions were reported as distress indicator. Capybaras[ vocal repertoire was reported recently and seems to have ultrasound calls, but this has not yet been confirmed. Thus, in order to check if a poor state of welfare was linked to ultrasound calls in the capybara vocal repertoire, the aim of this study was to track the presence of ultrasound emissions in 11 animals under three conditions: 1 unrestrained; 2 intermediately restrained, and 3 highly restrained. The ultrasound track identified frequencies in the range of 31.8±3.5 kHz in adults and 33.2±8.5 kHz in juveniles. These ultrasound frequencies occurred only when animals were highly restrained, physically restrained or injured during handling. We concluded that these calls with ultrasound components are related to pain and restraint because they did not occur when animals were free of restraint. Thus we suggest that this vocalization may be used as an additional tool to assess capybaras[ welfare.

  10. A Concept of Dark Age Interferometric Array (DAIA)

    Yan, Jingye

    After the epoch of recombination the Universe remained in neutral state until the large scale formation of galaxies released a sufficient number of ionizing photons to lightning the universe. In this period, the only emission is from the 21cm wavelength neutral hydrogen that may be observed today at 0.5-30MHz after the red shift. However, due to the ionosphere block and human/industrial RFI in this band, to observe the space from ground and also in the LOE is not possible. The concept of Dark Age Interferometric Array (DAIA) is aimed to place a linear array of nano-satellite with low noise receivers at the 10-1000m wavelength band in a lunar orbit. The distances between the nano-satellites are designed to form 1D uniformly distributed base lines in the uv-plane. A full coverage is then obtained after half rotation of the array in the orbit. The measurements are taken in the far side of the moon in order to have the lowest RFI from the earth. The thinned synthetic aperture linear array composed of ~15 elements (one small mother satellite and 14 nano daughter satellites) with the longest baseline over 100km. There are 3 dipoles antennas on each satellite in perpendicular to each other. Each of the antenna connected with a low-noise and periodically calibrated digital receiver. The received signals from each element are all sent to the mother satellite and processed onboard to generate the visibility functions for image processing. The mission composed of a mother satellite and 14 daughter satellites. The mass of the mother is ~110kg, and the mass of each daughter is <10kg. The complete set may be launched by CZ-2D carrier plus an upper stage or Vega. The mother satellite and 14 daughter satellites are bound onto a single structure during launch. When they arrive at the lunar orbit, the mother will release the daughters one by one according to the designs of the element spacing of the array with a controlled period of time. During the operation, daughters receive

  11. Recursive Ultrasound Imaging

    Nikolov, Svetoslav; Gammelmark, Kim; Jensen, Jørgen Arendt

    1999-01-01

    This paper presents a new imaging method, applicable for both 2D and 3D imaging. It is based on Synthetic Transmit Aperture Focusing, but unlike previous approaches a new frame is created after every pulse emission. The elements from a linear transducer array emit pulses one after another. The sa...

  12. Ultrasound despeckling for contrast enhancement.

    Tay, Peter C; Garson, Christopher D; Acton, Scott T; Hossack, John A

    2010-07-01

    Images produced by ultrasound systems are adversely hampered by a stochastic process known as speckle. A despeckling method based upon removing outlier is proposed. The method is developed to contrast enhance B-mode ultrasound images. The contrast enhancement is with respect to decreasing pixel variations in homogeneous regions while maintaining or improving differences in mean values of distinct regions. A comparison of the proposed despeckling filter is compared with the other well known despeckling filters. The evaluations of despeckling performance are based upon improvements to contrast enhancement, structural similarity, and segmentation results on a Field II simulated image and actual B-mode cardiac ultrasound images captured in vivo. PMID:20227984

  13. Are shoulder surgeons any good at diagnosing rotator cuff tears using ultrasound?: A comparative analysis of surgeon vs radiologist

    Jeyam Muthu

    2008-01-01

    Full Text Available High-resolution ultrasound has gained increasing popularity as an aid in the diagnosis of rotator cuff pathology. With the advent of portable machines, ultrasound has become accessible to clinicians. Aim: This study was conducted to evaluate the accuracy and reliability of ultrasound in diagnosing rotator cuff tears by a shoulder surgeon and comparing their ability to that of a musculoskeletal radiologist. Materials and Methods: Seventy patients undergoing shoulder arthroscopy for rotator cuff pathology underwent preoperative ultrasonography (US. All patients were of similar demographics and pathology. The surgeon used a Sonosite Micromax portable ultrasound machine with a 10-MHz high frequency linear array transducer and the radiologist used a 9-12 MHz linear array probe on a Siemens Antares machine. Arthroscopic diagnosis was the reference standard to which ultrasound findings were compared. Results: The sensitivity in detecting full thickness tears was similar for both the surgeon (92% and the radiologist (94%. The radiologist had 100% sensitivity in diagnosing partial thickness tears, compared to 85.7% for the surgeon. The specificity for the surgeon was 94% and 85% for the radiologist. Discussion: Our study shows that the surgeons are capable of diagnosing rotator cuff tears with the use of high-resolution portable ultrasound in the outpatient setting. Conclusion: Office ultrasound, by a trained clinician, is a powerful diagnostic tool in diagnosing rotator cuff tears and can be used effectively in running one-stop shoulder clinics.

  14. Modeling of higher harmonics formation in medical ultrasound systems

    Taylor, Louise Kold; Schlaikjer, Malene; Jensen, Jørgen Arendt

    The pressure eld emitted from multi-element medical ultrasound transducers can be simulated with Field II in the linear regime. By expanding this program's application to the nonlinear regime, beamforming schemes can be studied under strong focusing and high pressure levels as well, providing a...... valuable tool for simulating ultrasound harmonic imaging. An extended version of Field II is obtained by means of operator splitting. The pressure eld is calculated by propagation of the eld from the transducer through a number of planes. Every plane serves as a virtual aperture for the next plane, and...... the approach is demonstrated by comparing results from simulations and measurements from a convex array transducer. The new simulation tool is capable of simulating the formation of higher harmonics in water on the acoustical axis. The generation of nonlinear higher harmonic components can be...

  15. Stone fragmentation by ultrasound

    S K Shrivastava; Kailash

    2004-08-01

    The presence of kidney stone in the kidney causes discomfort to patients. Hence, removal of such stones is important which is commonly done these days, non-destructively, with lithotripters without surgery. Commercially, lithotripters like extra-corporeal shock wave lithotripters (ESWL) made by Siemens etc are in routine use. These methods are very cumbersome and expensive. Treatment of the patients also takes comparatively more time because of more number of sittings. Some delicate nerves and fibres in the surrounding areas of the stones present in the kidney are also damaged by high ultrasonic intensity used in such systems. In the present work, enhancement of the kidney stone fragmentation by using ultrasound is studied. The cavitation bubbles are found to implode faster, with more disintegration efficiency of the lithotripters, which give better treatment to the patients.

  16. Ultrasound of Sternal Fracture

    Shadi Lahham

    2015-12-01

    Full Text Available A 61-year-old female was brought in by ambulance after being the restrained driver of a head-on motor vehicle collision at 40MPH. There was positive airbag deployment and intrusion from the other vehicle. During workup, the patient complained of midline chest pain, and left chest wall pain. The patient was not in acute respiratory distress, and had the following vital signs: temperature 37°C, heart rate 84, blood pressure of 150/64, respiratory rate 18, and oxygen saturation of 97% on two liters of oxygen. On physical exam, breath sounds were heard bilaterally, with no acute cardiopulmonary issues identified. A bruise was identified on the lower abdomen, which was thought to be a potential seatbelt sign. A focused assessment with sonography for trauma was negative, and an ultrasound of additional chest and mediastinal structures was performed for the chest tenderness.

  17. Children's (Pediatric) Abdominal Ultrasound Imaging

    Full Text Available ... Videos related to Children's (Pediatric) Ultrasound - Abdomen About this Site RadiologyInfo.org is produced by: Please note ... you can search the ACR-accredited facilities database . This website does not provide cost information. The costs ...

  18. Children's (Pediatric) Abdominal Ultrasound Imaging

    Full Text Available ... over time. top of page What are the benefits vs. risks? Benefits Most ultrasound scanning is noninvasive (no needles or ... the possible charges you will incur. Web page review process: This Web page is reviewed regularly by ...

  19. Children's (Pediatric) Abdominal Ultrasound Imaging

    Full Text Available ... 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 ...

  20. Children's (Pediatric) Abdominal Ultrasound Imaging

    Full Text Available ... between the transducer and the skin that can block the sound waves from passing into your body. ... to-use and less expensive than other imaging methods. Ultrasound imaging is extremely safe and does not ...

  1. Ultrasound-modulated bioluminescence tomography

    Bal, Guillaume; Schotland, John C.

    2014-03-01

    We propose a method to reconstruct the density of a luminescent source in a highly scattering medium from ultrasound-modulated optical measurements. Our approach is based on the solution to a hybrid inverse source problem for the diffusion equation.

  2. Children's (Pediatric) Abdominal Ultrasound Imaging

    Full Text Available ... technique that allows the physician to see and evaluate blood flow through arteries and veins in the ... the procedure? Abdominal ultrasound imaging is performed to evaluate the: appendix stomach/ pylorus liver gallbladder spleen pancreas ...

  3. The Belfast musculoskeletal ultrasound course.

    Taggart, Allister J

    2009-09-01

    To conduct a training course in musculoskeletal ultrasound (MSUS) for rheumatologists in Northern Ireland with the aim of equipping the participants with a basic knowledge of the theoretical and practical aspects of MSUS as they are applied to rheumatology.

  4. Ultrasound diagnostics of postpartum endometritis

    Bratchikova О.А.; Chekhonatskaya M.L.; Yannaeva N.E.

    2014-01-01

    The purpose of the article is to present data on diagnostics of postpartum infectious diseases in women in childbirth. The aim of the conducted survey is to study modern ultrasound diagnostic methods of the given pathology.

  5. Neuromuscular Ultrasound of Cranial Nerves

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

    2015-01-01

    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 re...

  6. Ultrasound in environmental engineering II

    Neis, U. (ed.)

    2002-07-01

    This book has been compiled from presentations held from March 21 to 22, 2002, at the second Symposium on 'Ultrasound in Environmental Engineering' at the Technical University of Hamburg-Harburg in co-operation with the German Association for the Water Environment (ATV-DVWK) and the DECHEMA e.V. The Symposium was loosely grouped into the following themes: recent developments with respect to ultrasound application, combined processes, design of sonoreactors, disinfection, potable water processing, waste water and biosolids treatment thus reflecting the broad range of interesting existing and potential applications of ultrasound in environmental protection. According to that order the articles appear in this book. They deal with recent research and state-of-the-art information on the scientific basis, modes of use, and engineering developments of ultrasound application in the field of environmental protection. Ultrasound is generated and applied across a large range of frequencies from 20 kHz to several MHz. Reactor design, applied intensity, duration of sonication, and physicochemical parameters of the sonicated media influence ultrasound effects. Also often, when it comes to discuss the economy of the ultrasound technique one encounters reservations related to the energy consumption of such systems. Thus, ultrasound, at a first glance, is a complex and probably confusing matter. This is the reason why we felt it useful to organise the second Symposium of that kind after we had the first in 1999. The purpose was to bring together the experience and knowledge from a broad spectrum of disciplines such as chemists, manufacturers, plant designers and operators, universities and research institutions to focus on and summarise the latest know-how and developments in this interesting new environmental protection technology. (orig.)

  7. Despeckling of Medical Ultrasound Images

    Michailovich, Oleg V.; Tannenbaum, Allen

    2006-01-01

    Speckle noise is an inherent property of medical ultrasound imaging, and it generally tends to reduce the image resolution and contrast, thereby reducing the diagnostic value of this imaging modality. As a result, speckle noise reduction is an important prerequisite, whenever ultrasound imaging is used for tissue characterization. Among the many methods that have been proposed to perform this task, there exists a class of approaches that use a multiplicative model of speckled image formation ...

  8. Ultrasound Despeckling for Contrast Enhancement

    Tay, Peter C.; Garson, Christopher D.; Acton, Scott T.; Hossack, John A.

    2010-01-01

    Images produced by ultrasound systems are adversely hampered by a stochastic process known as speckle. A despeckling method based upon removing outlier is proposed. The method is developed to contrast enhance B-mode ultrasound images. The contrast enhancement is with respect to decreasing pixel variations in homogeneous regions while maintaining or improving differences in mean values of distinct regions. A comparison of the proposed despeckling filter is compared with the other well known de...

  9. Ultrasound in environmental engineering. Papers

    Tiehm, A.; Neis, U. [eds.

    1999-07-01

    This book presents recent research and state-of-the-art information on the scientific basis, modes of use, and engineering developments of ultrasound application in the field of environmental protection. The information is loosely grouped into the following themes: ultrasound and sonochemistry, design of sonoreactors, applications in water, waste water and sludge treatment: aggregation of suspended particles, degradation of hazardous pollutants, disinfection, disintegration of biosolids. Ultrasound is generated and applied at frequencies from 20 kHz to several MHz. Reactor design, applied intensity, duration of sonication, and physico-chemical parameters of the sonicated media influence ultrasound effects. Thus, ultrasound, at a first glance, is a complex and probably confusing matter. This book has been compiled from presentations held at the first workshop 'Ultrasound in Environmental Engineering' on March 22nd and 23rd, 1999, at the Technical University of Hamburg-Harburg in cooperation with the German Association for the Water Environment (ATV) and the DECHEMA e.V. (orig.)

  10. Determination of lesion size by ultrasound during radiofrequency catheter ablation.

    Awad, S; Eick, O

    2003-01-01

    The catheter tip temperature that is used to control the radiofrequency generator output poorly correlates to lesion size. We, therefore, evaluated lesions created in vitro using a B-mode ultrasound imaging device as a potential means to assess lesion generation during RF applications non-invasively. Porcine ventricular tissue was immersed in saline solution at 37 degrees C. The catheter was fixed in a holder and positioned in a parallel orientation to the tissue with an array transducer (7.5 MHz) app. 3 cm above the tissue. Lesions were produced either in a temperature controlled mode with a 4-mm tip catheter with different target temperatures (50, 60, 70 and 80 degrees C, 80 W maximum output) or in a power controlled mode (25, 50 and 75 W, 20 ml/min irrigation flow) using an irrigated tip catheter. Different contact forces (0.5 N, 1.0 N) were tested, and RF was delivered for 60 s. A total of 138 lesions was produced. Out of these, 128 could be identified on the ultrasound image. The lesion depth and volume was on average 4.1 +/- 1.6 mm and 52 +/- 53 mm3 as determined by ultrasound and 3.9 +/- 1.7 mm and 52 +/- 55 mm3 as measured thereafter, respectively. A linear correlation between the lesion size determined by ultrasound and that measured thereafter was demonstrated with a correlation coefficient of r = 0.87 for lesion depth and r = 0.93 for lesion volume. We conclude that lesions can be assessed by B-mode ultrasound imaging. PMID:12910859

  11. Ultrasound as a Screening Tool for Performing Caudal Epidural Injections

    The caudal approach to the epidural space has been used for decades to treat low back pain caused by lumbosacral root compression. The use of fluoroscopy during epidural steroid injection is the preferred method for placing the needle more accurately in the sacral hiatus, but it carries the risk of radiation hazard. The aim of the study was to assess the anatomical structure of the sacral hiatus and the feasibility of caudal epidural injections under ultrasound guidance. Two hundred and forty patients (male = 100, female = 140) with low back pain and sciatica who were candidates for caudal epidural injection were enrolled into this study. Ultrasound images of the sacral hiatus and bilateral cornua were obtained by a real-time linear array ultrasound transducer. The distance between bilateral cornua and the anterior and posterior wall of the sacrum were measured at the base (sacral hiatus). Under the guide of ultrasonography, we defined the injection successful if turbulence of medication fluid was observed in the sacral canal, but correct placement of the needle and injectant was confirmed on fluoroscopic view as the gold standard technique. The epidurogram showed that the injection was successful in 230 of the 240 patients (95.8%). In eight patients, the injection was not in the correct place in the sacral canal. The sacral hiatus could not be identified by ultrasound images in only two patients who had a closed sacral hiatus identified by fluoroscopy. The mean distance of the sacral hiatus was 4.7 ± 1.7 mm and the mean distance between bilateral cornua was 18.0 ± 2.8 mm. The mean duration of the procedure was 10.8 ± 6.8 minutes. No major complication was observed in the next month. In conclusion, ultrasound could be used as a safe, fast and reliable modality to observe the anatomic variation of the sacral hiatus and to perform caudal epidural injections

  12. Numerical simulations of clinical focused ultrasound functional neurosurgery

    Pulkkinen, Aki; Werner, Beat; Martin, Ernst; Hynynen, Kullervo

    2014-04-01

    A computational model utilizing grid and finite difference methods were developed to simulate focused ultrasound functional neurosurgery interventions. The model couples the propagation of ultrasound in fluids (soft tissues) and solids (skull) with acoustic and visco-elastic wave equations. The computational model was applied to simulate clinical focused ultrasound functional neurosurgery treatments performed in patients suffering from therapy resistant chronic neuropathic pain. Datasets of five patients were used to derive the treatment geometry. Eight sonications performed in the treatments were then simulated with the developed model. Computations were performed by driving the simulated phased array ultrasound transducer with the acoustic parameters used in the treatments. Resulting focal temperatures and size of the thermal foci were compared quantitatively, in addition to qualitative inspection of the simulated pressure and temperature fields. This study found that the computational model and the simulation parameters predicted an average of 24 ± 13% lower focal temperature elevations than observed in the treatments. The size of the simulated thermal focus was found to be 40 ± 13% smaller in the anterior-posterior direction and 22 ± 14% smaller in the inferior-superior direction than in the treatments. The location of the simulated thermal focus was off from the prescribed target by 0.3 ± 0.1 mm, while the peak focal temperature elevation observed in the measurements was off by 1.6 ± 0.6 mm. Although the results of the simulations suggest that there could be some inaccuracies in either the tissue parameters used, or in the simulation methods, the simulations were able to predict the focal spot locations and temperature elevations adequately for initial treatment planning performed to assess, for example, the feasibility of sonication. The accuracy of the simulations could be improved if more precise ultrasound tissue properties (especially of the

  13. Numerical simulations of clinical focused ultrasound functional neurosurgery

    A computational model utilizing grid and finite difference methods were developed to simulate focused ultrasound functional neurosurgery interventions. The model couples the propagation of ultrasound in fluids (soft tissues) and solids (skull) with acoustic and visco-elastic wave equations. The computational model was applied to simulate clinical focused ultrasound functional neurosurgery treatments performed in patients suffering from therapy resistant chronic neuropathic pain. Datasets of five patients were used to derive the treatment geometry. Eight sonications performed in the treatments were then simulated with the developed model. Computations were performed by driving the simulated phased array ultrasound transducer with the acoustic parameters used in the treatments. Resulting focal temperatures and size of the thermal foci were compared quantitatively, in addition to qualitative inspection of the simulated pressure and temperature fields. This study found that the computational model and the simulation parameters predicted an average of 24 ± 13% lower focal temperature elevations than observed in the treatments. The size of the simulated thermal focus was found to be 40 ± 13% smaller in the anterior–posterior direction and 22 ± 14% smaller in the inferior–superior direction than in the treatments. The location of the simulated thermal focus was off from the prescribed target by 0.3 ± 0.1 mm, while the peak focal temperature elevation observed in the measurements was off by 1.6 ± 0.6 mm. Although the results of the simulations suggest that there could be some inaccuracies in either the tissue parameters used, or in the simulation methods, the simulations were able to predict the focal spot locations and temperature elevations adequately for initial treatment planning performed to assess, for example, the feasibility of sonication. The accuracy of the simulations could be improved if more precise ultrasound tissue properties (especially of the

  14. Compensated Row-Column Ultrasound Imaging System Using Fisher Tippett Multilayered Conditional Random Field Model.

    Ibrahim Ben Daya

    Full Text Available 3-D ultrasound imaging offers unique opportunities in the field of non destructive testing that cannot be easily found in A-mode and B-mode images. To acquire a 3-D ultrasound image without a mechanically moving transducer, a 2-D array can be used. The row column technique is preferred over a fully addressed 2-D array as it requires a significantly lower number of interconnections. Recent advances in 3-D row-column ultrasound imaging systems were largely focused on sensor design. However, these imaging systems face three intrinsic challenges that cannot be addressed by improving sensor design alone: speckle noise, sparsity of data in the imaged volume, and the spatially dependent point spread function of the imaging system. In this paper, we propose a compensated row-column ultrasound image reconstruction system using Fisher-Tippett multilayered conditional random field model. Tests carried out on both simulated and real row-column ultrasound images show the effectiveness of our proposed system as opposed to other published systems. Visual assessment of the results show our proposed system's potential at preserving detail and reducing speckle. Quantitative analysis shows that our proposed system outperforms previously published systems when evaluated with metrics such as Peak Signal to Noise Ratio, Coefficient of Correlation, and Effective Number of Looks. These results show the potential of our proposed system as an effective tool for enhancing 3-D row-column imaging.

  15. The study of laser array generation of elastic shear wave and surface wave

    The principle of laser light generation of ultrasound is the result of the absorption of light energy by the sample medium that is converted into thermal stress. From literature survey, single laser-generated ultrasound has some limitations. First, the high energy from laser light may cause the ablation on the material surface. Second, the single laser beam generation method is hard to control the beam-width and focusing direction of ultrasound. Third, the single laser-generated ultrasound is unable to enhance the ultrasound signal. The optical fiber phased array generation of ultrasound offer the improvement of the control of the beam-width and focusing direction, and to increase the amplitude of the generated ultrasound in the thermoelastic range. This research investigated the directivity pattern from the in-phased laser array generation of shear wave and surface wave in comparison with old and improved theoretical model. The theoretical data which was filtered by the electronic instruments were compared with the literature data, also.

  16. Ultrasound-guided removal of foreign bodies: personal experience.

    Callegari, Leonardo; Leonardi, Anna; Bini, Amedeo; Sabato, Chiara; Nicotera, Paolo; Spano', Emanuela; Mariani, Davide; Genovese, Eugenio A; Fugazzola, Carlo

    2009-05-01

    Foreign bodies (FBs) retained in the soft tissues are a common reason for medical consultation, and usually consist of wooden or metal splinters or glass shards. Failure to remove foreign bodies is likely to give rise to acute or late complications, such as allergies, inflammation or infection, that may be severe. The surgical removal of an FB is invasive, costly and technically challenging. The procedure may fail in some cases and carries the risk of complications. Our study describes a technique for the ultrasound-guided removal of an FB, devised from our experience, and demonstrates its advantages over the standard surgical procedure. Sixty-two patients (43 males and 19 females aged from 9 to 65 years, median age 31 years) presented at our institution between October 2005 and June 2008 with suspected foreign bodies retained in the soft tissues of various body districts. Radiographic and/or ultrasound diagnosis was established by a radiologist expert in musculoskeletal sonography. The same radiologist helped by a nurse subsequently undertook the ultrasound-guided removal in the outpatient's clinic according to the technique described in the paper. ATL 5000 and PHILIPS iu22 ultrasound systems were used with high-frequency linear-array probes, sterile material, local anaesthetic (lidocaine 2%), scapels and surgical forceps. Antibiotic prophylaxis with amoxicillin and clavulanic acid were prescribed to all patients for 7 days after the procedure. Ninety-five FBs (39 glass, 35 metal, 17 vegetable, 2 plastic, 2 stone) were successfully removed under ultrasound guidance in all patients and the procedure took between 15 and 30 min. No complications arose either during or after the procedure. Seventy-five skin incisions were made and the wounds closed with Steri-Strips in 73/75 cases, whereas skin sutures were used in 2/75 cases. No complications arose either during or after the procedure. Ultrasound-guided removal of an FB retained in the soft tissues is a good

  17. Feasibility of Swept Synthetic Aperture Ultrasound Imaging.

    Bottenus, Nick; Long, Will; Zhang, Haichong K; Jakovljevic, Marko; Bradway, David P; Boctor, Emad M; Trahey, Gregg E

    2016-07-01

    Ultrasound image quality is often inherently limited by the physical dimensions of the imaging transducer. We hypothesize that, by collecting synthetic aperture data sets over a range of aperture positions while precisely tracking the position and orientation of the transducer, we can synthesize large effective apertures to produce images with improved resolution and target detectability. We analyze the two largest limiting factors for coherent signal summation: aberration and mechanical uncertainty. Using an excised canine abdominal wall as a model phase screen, we experimentally observed an effective arrival time error ranging from 18.3 ns to 58 ns (root-mean-square error) across the swept positions. Through this clutter-generating tissue, we observed a 72.9% improvement in resolution with only a 3.75 dB increase in side lobe amplitude compared to the control case. We present a simulation model to study the effect of calibration and mechanical jitter errors on the synthesized point spread function. The relative effects of these errors in each imaging dimension are explored, showing the importance of orientation relative to the point spread function. We present a prototype device for performing swept synthetic aperture imaging using a conventional 1-D array transducer and ultrasound research scanner. Point target reconstruction error for a 44.2 degree sweep shows a reconstruction precision of 82.8 μm and 17.8 μm in the lateral and axial dimensions respectively, within the acceptable performance bounds of the simulation model. Improvements in resolution, contrast and contrast-to-noise ratio are demonstrated in vivo and in a fetal phantom. PMID:26863653

  18. Event building and reconstruction at 30 MHz using a CPU farm

    The LHCb experiment will be upgraded between 2018 and 2019 in order to reach unprecedented precision on the measurements of the main observables of the beauty and charm quarks. This paper describes the trigger-less readout system foreseen for the upgrade

  19. Event building and reconstruction at 30 MHz using a CPU farm

    Albrecht, J.; Campora, D.; Gligorov, V.; Jost, B.; Marconi, U.; Neufeld, N.; Raven, G.; Schwemmer, R.

    2014-10-01

    The LHCb experiment will be upgraded between 2018 and 2019 in order to reach unprecedented precision on the measurements of the main observables of the beauty and charm quarks. This paper describes the trigger-less readout system foreseen for the upgrade.

  20. Crosstalk Models for Short VDSL2 Lines from Measured 30 MHz Data

    Leshem A

    2006-01-01

    Full Text Available In recent years, there has been a growing interest in hybrid fiber-copper access solutions, as in fiber to the basement (FTTB and fiber to the curb/cabinet (FTTC. The twisted pair segment in these architectures is in the range of a few hundred meters, thus supporting transmission over tens of MHz. This paper provides crosstalk models derived from measured data for quad cable, lengths between 75 and 590 meters, and frequencies up to MHz. The results indicate that the log-normal statistical model (with a simple parametric law for the frequency-dependent mean fits well up to MHz for both FEXT and NEXT. This extends earlier log-normal statistical modeling and validation results for NEXT over bandwidths in the order of a few MHz. The fitted crosstalk power spectra are useful for modem design and simulation. Insertion loss, phase, and impulse response duration characteristics of the direct channels are also provided.

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

    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. PMID:20036873

  2. Angular spectrum approach for fast simulation of pulsed non-linear ultrasound fields

    Du, Yigang; Jensen, Henrik; Jensen, Jørgen Arendt

    The paper presents an Angular Spectrum Approach (ASA) for simulating pulsed non-linear ultrasound fields. The source of the ASA is generated by Field II, which can simulate array transducers of any arbitrary geometry and focusing. The non-linear ultrasound simulation program - Abersim, is used as...... the fundamental and keep the second harmonic field, since Abersim simulates non-linear fields with all harmonic components. ASA and Abersim are compared for the pulsed fundamental and second harmonic fields in the time domain at depths of 30 mm, 40 mm (focal depth) and 60 mm. Full widths at -6 d...

  3. Physics of tissue harmonic imaging by ultrasound

    Jing, Yuan

    Tissue Harmonic Imaging (THI) is an imaging modality that is currently deployed on diagnostic ultrasound scanners. In THI the amplitude of the ultrasonic pulse that is used to probe the tissue is large enough that the pulse undergoes nonlinear distortion as it propagates into the tissue. One result of the distortion is that as the pulse propagates energy is shifted from the fundamental frequency of the source pulse into its higher harmonics. These harmonics will scatter off objects in the tissue and images formed from the scattered higher harmonics are considered to have superior quality to the images formed from the fundamental frequency. Processes that have been suggested as possibly responsible for the improved imaging in THI include: (1) reduced sensitivity to reverberation, (2) reduced sensitivity to aberration, and (3) reduction in side lobes. By using a combination of controlled experiments and numerical simulations, these three reasons have been investigated. A single element transducer and a clinical ultrasound scanner with a phased array transducer were used to image a commercial tissue-mimicking phantom with calibrated targets. The higher image quality achieved with THI was quantified in terms of spatial resolution and "clutter" signals. A three-dimensional model of the forward propagation of nonlinear sound beams in media with arbitrary spatial properties (a generalized KZK equation) was developed. A time-domain code for solving the KZK equation was validated with measurements of the acoustic field generated by the single element transducer and the phased array transducer. The code was used to investigate the impact of aberration using tissue-like media with three-dimensional variations in all acoustic properties. The three-dimensional maps of tissue properties were derived from the datasets available through the Visible Female project. The experiments and simulations demonstrated that second harmonic imaging (1) suffers less clutter associated with

  4. ROLE OF ULTRASOUND IN THYROID DISORDERS

    Janani Parkkunam; Balasubramanian Thiagarajan

    2015-01-01

    Ultrasonography has established itself has a useful tool in evaluating and managing thyroid disorders. This article provides an overview of basic principles of ultrasound, how it is used in different thyroid disorders, different sonographic pattern of thyroid disorders, comparative features of malignant and benign nodule, ultrasound features of diffuse thyroid disorders and congenital thyroid disorders, ultrasound guided FNAC, advanced techniques of ultrasound in thyroid imaging.

  5. Microfocused ultrasound for facial rejuvenation: current perspectives

    Day, Doris

    2014-01-01

    Doris Day Day Dermatology and Aesthetics, New York, NY, USA Abstract: In contrast with ultrasound imaging, therapeutic ultrasound uses high energy levels >5 W/cm2 and is tightly focused into a small point to rapidly heat and coagulate targeted tissues. The use of high intensity focused ultrasound has recently expanded from high-precision surgical procedures into the field of noninvasive cosmetic medicine. Microfocused ultrasound (MFU) differs from other energy technologies used for sk...

  6. Optical detection of ultrasound from optically rough surfaces using a custom CMOS sensor

    The optical detection of ultrasound from optically rough surfaces is severely limited when using a conventional interferometric or optical beam deflection (OBD) setup because the detected light is speckled. This means that complicated and expensive setups are required to detect ultrasound optically on rough surfaces. We present a CMOS integrated circuit that can detect laser ultrasound in the presence of speckle. The detector circuit is based on the simple knife edge detector. It is self-adapting and is fast, inxepensive, compact and robust. The CMOS circuit is implemented as a widefield array of 32×32 pixels. At each pixel the received light is compared with an adjacent pixel in order to determine the local light gradient. The result of this comparison is stored and used to connect each pixel to the positive or negative gradient output as appropriate (similar to a balanced knife edge detector). The perturbation of the surface due to ultrasound preserves the speckle distribution whilst deflecting it. The spatial disturbance of the speckle pattern due to the ultrasound is detected by considering each pair of pixels as a knife edge detector. The sensor can adapt itself to match the received optical speckle pattern in less than 0.1 μs, and then detect the ultrasound within 0.5 μs of adaptation. This makes it possible to repeatedly detect ultrasound from optically rough surfaces very quickly. The detector is capable of independent operation controlled by a local microcontroller, or it may be connected to a computer for more sophisticated configuration and control. We present the theory of its operation and discuss results validating the concept and operation of the device. We also present preliminary results from an improved design which grants a higher bandwidth, allowing for optical detection of higher frequency ultrasound

  7. Ultrasound: From Earth to Space

    Law, Jennifer; Macbeth, Paul. B.

    2011-01-01

    Ultrasonography is a versatile imaging modality that offers many advantages over radiography, computed tomography, and magnetic resonance imaging. On Earth, the use of ultrasound has become standard in many areas of medicine including diagnosis of medical and surgical diseases, management of obstetric and gynecologic conditions, assessment of critically ill patients, and procedural guidance. Advances in telecommunications have enabled remotely-guided ultrasonography for both geographically isolated populations and astronauts aboard the International Space Station. While ultrasound has traditionally been used in spaceflight to study anatomical and physiological adaptations to microgravity and evaluate countermeasures, recent years have seen a growth of applications adapted from terrestrial techniques. Terrestrial, remote, and space applications for ultrasound are reviewed in this paper. PMID:22399873

  8. Impedance-controlled ultrasound probe

    Gilbertson, Matthew W.; Anthony, Brian W.

    2011-03-01

    An actuated hand-held impedance-controlled ultrasound probe has been developed. The controller maintains a prescribed contact state (force and velocity) between the probe and a patient's body. The device will enhance the diagnostic capability of free-hand elastography and swept-force compound imaging, and also make it easier for a technician to acquire repeatable (i.e. directly comparable) images over time. The mechanical system consists of an ultrasound probe, ball-screw-driven linear actuator, and a force/torque sensor. The feedback controller commands the motor to rotate the ball-screw to translate the ultrasound probe in order to maintain a desired contact force. It was found that users of the device, with the control system engaged, maintain a constant contact force with 15 times less variation than without the controller engaged. The system was used to determine the elastic properties of soft tissue.

  9. Image processing in medical ultrasound

    Hemmsen, Martin Christian

    This Ph.D project addresses image processing in medical ultrasound and seeks to achieve two major scientific goals: First to develop an understanding of the most significant factors influencing image quality in medical ultrasound, and secondly to use this knowledge to develop image processing...... multiple imaging setups. This makes the system well suited for development of new processing methods and for clinical evaluations, where acquisition of the exact same scan location for multiple methods is important. The second project addressed implementation, development and evaluation of SASB using a...... methods for enhancing the diagnostic value of medical ultrasound. The project is an industrial Ph.D project co-sponsored by BK Medical ApS., with the commercial goal to improve the image quality of BK Medicals scanners. Currently BK Medical employ a simple conventional delay-and-sum beamformer to generate...

  10. Three-dimensional ultrasound palmprint recognition using curvature methods

    Iula, Antonio; Nardiello, Donatella

    2016-05-01

    Palmprint recognition systems that use three-dimensional (3-D) information of the palm surface are the most recently explored techniques to overcome some two-dimensional palmprint difficulties. These techniques are based on light structural imaging. In this work, a 3-D ultrasound palmprint recognition system is proposed and evaluated. Volumetric images of a region of the human hand are obtained by moving an ultrasound linear array along its elevation direction and one by one acquiring a number of B-mode images, which are then grouped in a 3-D matrix. The acquisition time was contained in about 5 s. Much information that can be exploited for 3-D palmprint recognition is extracted from the ultrasound volumetric images, including palm curvature and other under-skin information as the depth of the various traits. The recognition procedure developed in this work is based on the analysis of the principal curvatures of palm surface, i.e., mean curvature image, Gaussian curvature image, and surface type. The proposed method is evaluated by performing verification and identification experiments. Preliminary results have shown that the proposed system exhibits an acceptable recognition rate. Further possible improvements of the proposed technique are finally highlighted and discussed.

  11. Measurement system for pulsed ultrasound wave propagation

    Sánchez-Palencia, Sara; Schraven, Stef; Böhner, Daniel; Pérez Carrera, Sergio

    2009-01-01

    An ultrasound measurement system is built for the „Section For Electrical And Mechanical Engineering” of the Oslo University College. The system will be used for research purposes. Ultrasound is used both in industrial applications and in medicine. The objective is to design, build and test a measurement system with water tank in order to compare the quality of different ultrasound transducers.

  12. Transverse Oscillation Vector Velocity Estimation using a Phased Array Transducer

    Marcher, Jønne; Pihl, Michael Johannes; Seerup, Gert;

    2012-01-01

    The Transverse Oscillation method has shown its commercial feasibility, providing the user with 2D velocity information. Todays implementation on commercial ultrasound platforms only support linear array transducers and are limited in depth. Extending the implementation to a phased array transduc...... leaves room for optimization. Despite the bias, the method has shown to work and produce reliable results, and 2D velocity estimates are provided within the entire color-box down to a depth of more than 100 mm making vector velocity imaging possible in the entire heart....

  13. Simulator training for endobronchial ultrasound

    Konge, Lars; Clementsen, Paul Frost; Ringsted, Charlotte;

    2015-01-01

    Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is very operator dependent and has a long learning curve. Simulation-based training might shorten the learning curve, and an assessment tool with solid validity evidence could ensure basic competency before unsupervised......-trained novices and apprenticeship-trained novices failing the test, respectively; p<0.001.The endobronchial ultrasound assessment tool could be used to provide reliable and valid assessment of competence in EBUS-TBNA, and act as an aid in certification. Virtual-reality simulator training was shown to be more...

  14. Application of Ultrasound in Audiology

    Farzad Rahimi

    1993-01-01

    Diagnostic ultrasound is a beneficial technique which can be used the audiologists based on essential instruction. Although there are a lot of barriers in relation to the size of the probe and the resolution of the pictures which are obtained, with this method some kind of information can be gained that is impossible to get by any other method. The ability of real- time A and B modes for direct visualization makes them useful tools to study the changes of the ear structures. Ultrasound system...

  15. Virtual ultrasound sources in high-resolution ultrasound imaging

    Nikolov, Svetoslav; Jensen, Jørgen Arendt

    2002-01-01

    beamforming procedure for 3D ultrasound imaging. The position of the virtual source, and the created waveform are investigated with simulation, and with pulse-echo measurements. There is good agreement between the estimated wavefront and the theoretically tted one. Several examples of the use of virtual...

  16. CT and Ultrasound Guided Stereotactic High Intensity Focused Ultrasound (HIFU)

    To demonstrate the feasibility of CT and B-mode Ultrasound (US) targeted HIFU, a prototype coaxial focused ultrasound transducer was registered and integrated to a CT scanner. CT and diagnostic ultrasound were used for HIFU targeting and monitoring, with the goals of both thermal ablation and non-thermal enhanced drug delivery. A 1 megahertz coaxial ultrasound transducer was custom fabricated and attached to a passive position-sensing arm and an active six degree-of-freedom robotic arm via a CT stereotactic frame. The outer therapeutic transducer with a 10 cm fixed focal zone was coaxially mounted to an inner diagnostic US transducer (2-4 megahertz, Philips Medical Systems). This coaxial US transducer was connected to a modified commercial focused ultrasound generator (Focus Surgery, Indianapolis, IN) with a maximum total acoustic power of 100 watts. This pre-clinical paradigm was tested for ability to heat tissue in phantoms with monitoring and navigation from CT and live US. The feasibility of navigation via image fusion of CT with other modalities such as PET and MRI was demonstrated. Heated water phantoms were tested for correlation between CT numbers and temperature (for ablation monitoring). The prototype transducer and integrated CT/US imaging system enabled simultaneous multimodality imaging and therapy. Pre-clinical phantom models validated the treatment paradigm and demonstrated integrated multimodality guidance and treatment monitoring. Temperature changes during phantom cooling corresponded to CT number changes. Contrast enhanced or non-enhanced CT numbers may potentially be used to monitor thermal ablation with HIFU. Integrated CT, diagnostic US, and therapeutic focused ultrasound bridges a gap between diagnosis and therapy. Preliminary results show that the multimodality system may represent a relatively inexpensive, accessible, and simple method of both targeting and monitoring HIFU effects. Small animal pre-clinical models may be translated to large

  17. Feasibility of noninvasive ultrasound delivery for tumor ablation and targeted drug delivery in the brain

    Hynynen, Kullervo; McDannold, Nathan; Clement, Greg; White, Jason; Treat, Lisa; Yin, Xiangtao; Jolesz, Ferenc; Sheikov, Nickolai; Vykhodtseva, Natalia

    2005-04-01

    The objective of our research during the past few years has been to develop multichannel ultrasound phased arrays for noninvasive brain interventions. We have been successful in developing methods for correcting the skull induced beam distortions and thus, are able to produce sharp focusing through human skulls. This method is now being tested for thermal ablation of tumors, with results from animal studies demonstrating feasibility. In addition, the ability of ultrasound to open the blood-brain barrier (BBB) locally has been explored in animal models. The results suggest that the transcranial ultrasound exposures can induce BBB opening such that therapeutic agents can be localized in the brain. This tool is especially powerful since the beam can be guided by MR images, thus providing anatomical or functional targeting. This talk will review our current status in this research, which ultimately aims for the clinical use of this methodology.

  18. Ultrasound molecular imaging: Moving toward clinical translation

    Abou-Elkacem, Lotfi; Bachawal, Sunitha V.; Willmann, Jürgen K., E-mail: willmann@stanford.edu

    2015-09-15

    Highlights: • Ultrasound molecular imaging is a highly sensitive modality. • A clinical grade ultrasound contrast agent has entered first in human clinical trials. • Several new potential future clinical applications of ultrasound molecular imaging are being explored. - Abstract: Ultrasound is a widely available, cost-effective, real-time, non-invasive and safe imaging modality widely used in the clinic for anatomical and functional imaging. With the introduction of novel molecularly-targeted ultrasound contrast agents, another dimension of ultrasound has become a reality: diagnosing and monitoring pathological processes at the molecular level. Most commonly used ultrasound molecular imaging contrast agents are micron sized, gas-containing microbubbles functionalized to recognize and attach to molecules expressed on inflamed or angiogenic vascular endothelial cells. There are several potential clinical applications currently being explored including earlier detection, molecular profiling, and monitoring of cancer, as well as visualization of ischemic memory in transient myocardial ischemia, monitoring of disease activity in inflammatory bowel disease, and assessment of arteriosclerosis. Recently, a first clinical grade ultrasound contrast agent (BR55), targeted at a molecule expressed in neoangiogenesis (vascular endothelial growth factor receptor type 2; VEGFR2) has been introduced and safety and feasibility of VEGFR2-targeted ultrasound imaging is being explored in first inhuman clinical trials in various cancer types. This review describes the design of ultrasound molecular imaging contrast agents, imaging techniques, and potential future clinical applications of ultrasound molecular imaging.

  19. Ultrasound molecular imaging: Moving toward clinical translation

    Highlights: • Ultrasound molecular imaging is a highly sensitive modality. • A clinical grade ultrasound contrast agent has entered first in human clinical trials. • Several new potential future clinical applications of ultrasound molecular imaging are being explored. - Abstract: Ultrasound is a widely available, cost-effective, real-time, non-invasive and safe imaging modality widely used in the clinic for anatomical and functional imaging. With the introduction of novel molecularly-targeted ultrasound contrast agents, another dimension of ultrasound has become a reality: diagnosing and monitoring pathological processes at the molecular level. Most commonly used ultrasound molecular imaging contrast agents are micron sized, gas-containing microbubbles functionalized to recognize and attach to molecules expressed on inflamed or angiogenic vascular endothelial cells. There are several potential clinical applications currently being explored including earlier detection, molecular profiling, and monitoring of cancer, as well as visualization of ischemic memory in transient myocardial ischemia, monitoring of disease activity in inflammatory bowel disease, and assessment of arteriosclerosis. Recently, a first clinical grade ultrasound contrast agent (BR55), targeted at a molecule expressed in neoangiogenesis (vascular endothelial growth factor receptor type 2; VEGFR2) has been introduced and safety and feasibility of VEGFR2-targeted ultrasound imaging is being explored in first inhuman clinical trials in various cancer types. This review describes the design of ultrasound molecular imaging contrast agents, imaging techniques, and potential future clinical applications of ultrasound molecular imaging

  20. Elimination of therapeutic ultrasound noise from pre-beamformed RF data in ultrasound imaging for ultrasound-guided high-intensity focused ultrasound treatment

    Takagi, Ryo; Goto, Kota; Jimbo, Hayato; Matsuura, Keiko; Iwasaki, Ryosuke; Umemura, Shin-ichiro; Yoshizawa, Shin

    2015-07-01

    In conventional ultrasonic monitoring of high-intensity focused ultrasound (HIFU) treatment, a significant interval between consecutive HIFU shots is set for monitoring target tissue to avoid the interference of HIFU noise with RF echo signals. Thus, it is difficult to detect changes in tissue on the order of milliseconds, which are required to dynamically control the HIFU exposure. In this study, a new filtering method to eliminate the HIFU noise in the RF signals before beamforming is proposed. The CW response was estimated from RF signals with no pulse response to the imaging exposure, and the estimated CW response was subtracted from the entire RF signal to selectively eliminate the HIFU noise for each channel of the array probe before dynamic focusing was applied. The HIFU noise was selectively eliminated by this method when it existed. The results imply that the proposed filtering method is useful for true real-time detection of changes in tissue due to thermal coagulation during HIFU exposure.

  1. Enzyme extraction by ultrasound from sludge flocs

    YU Guanghui; HE Pinjing; SHAO Liming; ZHU Yishu

    2009-01-01

    Enzymes play essential roles in the biological processes of sludge treatment. In this article, the ultrasound method to extract enzymes from sludge flocs was presented. Results showed that using ultrasound method at 20 kHz could extract more types of enzymes than that ultrasound at 40 kHz and ethylenediamine tetraacetic acid (EDTA) methods. The optimum parameters of ultrasound extraction at 20 kHz were duration of 10 min and power of 480 W. Under the condition, ultrasound could break the cells and extract both the extracellular and intercellular enzymes. Ultrasound power was apparently more susceptive to enzyme extraction than duration, suggesting that the control of power during ultrasound extraction was more important than that of duration. The Pearson correlation analysis between enzyme activities and cation contents revealed that the different types of enzymes had distinct cation binding characteristics.

  2. Effect of Ultrasound on Desorption Equilibrium

    秦炜; 原永辉; 戴猷元

    2001-01-01

    Effects of ultrasound on intensification of separation process were investigated through the experiment of desorption equilibrium behavior. Tri-butyl phosphate (TBP) on NKA-X resin and phenol on a solvent impregnated resin, CL-TBP resin, were used for desorption processes. The desorption rate was measured with and without ultrasound. Desorption equilibrium was studied under various ultrasonic power densities or thermal infusion. Results showed that the desorption rate with ultrasound was much higher than that with normal thermal infusion. Both ultrasound and thermal infusion broke the desorption equilibrium existed at room temperature. However, after the systems were cooled down, the amount of solute desorbed in the liquid phase in the presence of ultrasound was much higher than that at the temperature corresponding to the same ultrasound power. It is proved that the initial desorption equilibrium was broken as a result of the spot energy effect of ultrasound.

  3. Children's (Pediatric) Abdominal Ultrasound Imaging

    Full Text Available ... gallbladder spleen pancreas intestines kidneys bladder testicles ovaries uterus Abdominal ultrasound images can be used to help ... that is being examined to the transducer (the device used to examine the patient), as well ... is not a medical facility. Please contact your physician with specific medical ...

  4. Ultrasound Imaging and its modeling

    Jensen, Jørgen Arendt

    2002-01-01

    Modern medical ultrasound scanners are used for imaging nearly all soft tissue structures in the body. The anatomy can be studied from gray-scale B-mode images, where the reflectivity and scattering strength of the tissues are displayed. The imaging is performed in real time with 20 to 100 images...

  5. Ultrasound fields from triangular apertures

    Jensen, Jørgen Arendt

    1996-01-01

    The pulsed field from a triangular aperture mounted in an infinite, rigidbaffle is calculated. The approach of spatial impulse responses,as developed by Tupholme and Stepanishen, is used. By this both the emitted and received pulsed ultrasound field can be found for any transducerexcitation and...

  6. Nonparametric estimation of ultrasound pulses

    Jensen, Jørgen Arendt; Leeman, Sidney

    1994-01-01

    An algorithm for nonparametric estimation of 1D ultrasound pulses in echo sequences from human tissues is derived. The technique is a variation of the homomorphic filtering technique using the real cepstrum, and the underlying basis of the method is explained. The algorithm exploits a priori...

  7. Endoscopic ultrasound via the esophagus

    Bødtger, Uffe; Clementsen, Paul; Annema, Jouke;

    2010-01-01

    "endoscopic ultrasound (EUS) and lung cancer" in PubMed was conducted. Invasive procedures (mediastinoscopy, thoracoscopy/-tomy) are the gold standard. The specificity of EUS was between 97 and 100%, and sensitivity 90 to 92%. The sensitivity was lower in studies published before 2000, and in computed...

  8. Children's (Pediatric) Abdominal Ultrasound Imaging

    Full Text Available ... torsion or twisting of a testicle limiting proper blood flow into it. top of page How should we prepare? Your child should be dressed in comfortable, loose-fitting clothing for an ultrasound exam. Other preparation depends on the type of examination. For some scans, your doctor may ...

  9. OSPACS: Ultrasound image management system

    Bessant Conrad

    2008-06-01

    Full Text Available Abstract Background Ultrasound scanning uses the medical imaging format, DICOM, for electronically storing the images and data associated with a particular scan. Large health care facilities typically use a picture archiving and communication system (PACS for storing and retrieving such images. However, these systems are usually not suitable for managing large collections of anonymized ultrasound images gathered during a clinical screening trial. Results We have developed a system enabling the accurate archiving and management of ultrasound images gathered during a clinical screening trial. It is based upon a Windows application utilizing an open-source DICOM image viewer and a relational database. The system automates the bulk import of DICOM files from removable media by cross-validating the patient information against an external database, anonymizing the data as well as the image, and then storing the contents of the file as a field in a database record. These image records may then be retrieved from the database and presented in a tree-view control so that the user can select particular images for display in a DICOM viewer or export them to external media. Conclusion This system provides error-free automation of ultrasound image archiving and management, suitable for use in a clinical trial. An open-source project has been established to promote continued development of the system.

  10. Children's (Pediatric) Abdominal Ultrasound Imaging

    Full Text Available ... children. It is also valuable for evaluating the brain, spinal cord and hip joints in newborns and infants. Risks For standard diagnostic ultrasound , there are no known harmful effects on humans. top of page What are the limitations of ...

  11. Medical ultrasound education for bioengineers

    Vaezy, Shahram

    2005-04-01

    The widespread adoption of ultrasound technologies in medicine has necessitated the development of educational programs to address the growing demand for trained expertise in both academia and industry. The demand has been especially great in the field of therapeutic ultrasound that has experienced a significant level of research and development activities in the past decade. The applications cover a wide range including cancer treatment, hemorrhage control, cardiac ablation, gene therapy, and cosmetic surgery. A comprehensive educational program in ultrasound is well suited for bioengineering departments at colleges and universities. Our educational program for students in Bioengineering at the University of Washington includes a year-long coursework covering theory and practice of ultrasound, conducting research projects, attending and presenting at weekly seminars on literature survey, presentations at scientific meetings, and attending specialized workshops offered by various institutions for specific topics. An important aspect of this training is its multi-disciplinary approach, encompassing science, engineering, and medicine. The students are required to build teams with expertise in these disciplines. Our experience shows that these students are well prepared for careers in academia, conducting cutting edge research, as well as industry, being involved in the transformation of research end-products to commercially viable technology.

  12. Children's (Pediatric) Abdominal Ultrasound Imaging

    Full Text Available ... barium exams, CT scanning , and MRI are the methods of choice in such a setting. Large patients are more difficult to image by ultrasound because greater amounts of tissue attenuate (weaken) the sound waves as they pass deeper into the body. top of page This page was reviewed on June ...

  13. Ultrasound Diagnostics of Premature Birth

    Chekhonatskaya M.L.; Vasilevich L.K.; Petrosyan N.O.; Kolesnikova E.A.

    2014-01-01

    The purpose of the article is to analyze the data of native and foreign literature and to consider the modern aspects of ultrasound diagnostics of premature birth, and new additional criteria for early diagnostics and prediction of preterm delivery. Hemodynamic characteristics in the second and third trimesters of the pregnancy have been covered.

  14. Computerized Ultrasound Risk Evaluation (CURE) System: Development of Combined Transmission and Reflection Ultrasound with New Reconstruction Algorithms for Breast Imaging

    Littrup, P J; Duric, N; Azevedo, S; Chambers, D; Candy, J V; Johnson, S; Auner, G; Rather, J; Holsapple, E T

    2001-09-07

    Our Computerized Ultrasound Risk Evaluation (CURE) system has been developed to the engineering prototype stage and generated unique data sets of both transmission and reflection ultrasound (US). This paper will help define the clinical underpinnings of the developmental process and interpret the imaging results from a similar perspective. The CURE project was designed to incorporate numerous diagnostic parameters to improve upon two major areas of early breast cancer detection. CURE may provide improved tissue characterization of breast masses and reliable detection of abnormal microcalcifications found in some breast cancers and ductal carcinoma in situ (DCIS). Current breast US is limited to mass evaluation, whereas mammography also detects and guides biopsy of malignant calcifications. Screening with CURE remains a distant goal, but improved follow-up of mammographic abnormalities may represent a feasible breakthrough. Improved tissue characterization could result in reduction of the estimated one million benign biopsies each year in the United States, costing up to several billion dollars. Most breast calcifications are benign and comprise-80% of stereotactic biopsies guided by mammography. Ultrasound has the capability of finding some groups of calcifications, but further improvements in resolution should also address tissue characterization to define the soft tissue filling of ducts by DCIS. In this manner, CURE may be able to more accurately identify the malignant calcifications associated with progression of DCIS or early cancers. Currently, high-resolution US images of the breast are performed in the reflection mode at higher frequencies, which also limits depth of penetration. Reconstruction of reflection ultrasound images relies upon acoustic impedance differences in the tissue and includes only direct backscatter of the ultrasound signal. Resolution and tissue contrast of current US continues to improve with denser transducer arrays and image

  15. Nonlinear acoustics in biomedical ultrasound

    Cleveland, Robin O.

    2015-10-01

    Ultrasound is widely used to image inside the body; it is also used therapeutically to treat certain medical conditions. In both imaging and therapy applications the amplitudes employed in biomedical ultrasound are often high enough that nonlinear acoustic effects are present in the propagation: the effects have the potential to be advantageous in some scenarios but a hindrance in others. In the case of ultrasound imaging the nonlinearity produces higher harmonics that result in images of greater quality. However, nonlinear effects interfere with the imaging of ultrasound contrast agents (typically micron sized bubbles with a strong nonlinear response of their own) and nonlinear effects also result in complications when derating of pressure measurements in water to in situ values in tissue. High intensity focused ultrasound (HIFU) is emerging as a non-invasive therapeutic modality which can result in thermal ablation of tissue. For thermal ablation, the extra effective attenuation resulting from nonlinear effects can result in enhanced heating of tissue if shock formation occurs in the target region for ablation - a highly desirable effect. However, if nonlinearity is too strong it can also result in undesired near-field heating and reduced ablation in the target region. The disruption of tissue (histotripsy) and fragmentation of kidney stones (lithotripsy) exploits shock waves to produce mechanically based effects, with minimal heating present. In these scenarios it is necessary for the waves to be of sufficient amplitude that a shock exists when the waveform reaches the target region. This talk will discuss how underlying nonlinear phenomenon act in all the diagnostic and therapeutic applications described above.

  16. Driving Circuitry for Focused Ultrasound Noninvasive Surgery and Drug Delivery Applications

    Kullervo Hynynen

    2011-01-01

    Full Text Available Recent works on focused ultrasound (FUS have shown great promise for cancer therapy. Researchers are continuously trying to improve system performance, which is resulting in an increased complexity that is more apparent when using multi-element phased array systems. This has led to significant efforts to reduce system size and cost by relying on system integration. Although ideas from other fields such as microwave antenna phased arrays can be adopted in FUS, the application requirements differ significantly since the frequency range used in FUS is much lower. In this paper, we review recent efforts to design efficient power monitoring, phase shifting and output driving techniques used specifically for high intensity focused ultrasound (HIFU.

  17. A Study of Laser-generated Ultrasound for Evaluation of Thickness Reduction in Piping System

    In carbon steel pipes of nuclear power plants, local wall thinning may result from erosion-corrosion or FAC(Flow Accelerated Corrosion) damage. Local wall thinning is one of the major causes for the structural fracture of these pipes. Therefore, assessment of local wall thinning due to corrosion is an important issue in nondestructive evaluation for the integrity of nuclear power plants. In this study, laser-generated ultrasound technique was employed to evaluate local wall thinning due to corrosion. Guided waves were generated in the thermoelastic regime using a Q-switched pulsed Nd:YAG laser with an linear array slit. Time-frequency analysis of ultrasonic waveforms using wavelet transform and FRT(Fast Fourier Transform) allowed the identification of generated guided wave modes by comparison with the theoretical dispersion curves. This study shows some experimental results about optimization of generating laser ultrasound using various linear array slits.

  18. Damage detection of carbon reinforced composites using nondestructive evaluation with ultrasound and electromagnetic methods

    Savin, A.; Barsanescu, P. D.; Vizureanu, P.; Stanciu, M. D.; Curtu, I.; Iftimie, N.; Steigmann, R.

    2016-06-01

    CFRP have applications among most different domains due their low density, high elastic modulus and high ultimate strength along the carbon fibers direction, no fatigue and the expansion coefficient is small. This paper presents the behavior of carbon fiber woven-PPS composites at low velocity impacts. The transversal electrical conductivity is modified due to the plastic deformation following the impacts, and thus electromagnetic procedures can be used for assessment of CFRP using a high resolution sensor with metamaterials lens and comparing the results with those obtained from ultrasound testing with phased array sensor. The area of the delamination is overestimated when the method of phased array ultrasound is used and substantially underestimated by the electromagnetic testing. There were a good agreement between the simulations with finite element method and experimental measurements.

  19. Fast simulation of non-linear pulsed ultrasound fields using an angular spectrum approach

    Du, Yigang; Jensen, Jørgen Arendt

    2013-01-01

    accuracy of the nonlinear ASA is compared to the non-linear simulation program – Abersim, which is a numerical solution to the Burgers equation based on the OSM. Simulations are performed for a linear array transducer with 64 active elements, focus at 40 mm, and excitation by a 2-cycle sine wave with a......A fast non-linear pulsed ultrasound field simulation is presented. It is implemented based on an angular spectrum approach (ASA), which analytically solves the non-linear wave equation. The ASA solution to the Westervelt equation is derived in detail. The calculation speed is significantly...... increased compared to a numerical solution using an operator splitting method (OSM). The ASA has been modified and extended to pulsed non-linear ultrasound fields in combination with Field II, where any array transducer with arbitrary geometry, excitation, focusing and apodization can be simulated. The...

  20. Optimization of ultrasound-assisted extraction of phenolic compounds from Cimicifugae rhizoma with response surface methodology

    Liu, Lin; Shen, Bao-Jia; Xie, Dong-Hao; Cai, Bao-chang; Qin, Kun-Ming; Cai, Hao

    2015-01-01

    Background: Cimicifugae rhizoma was a Ranunculaceae herb belonging to the composite family, and the roots of C. rhizoma have been widely used in tradition Chinese medicine. Materials and Methods: Ultrasound-assisted extraction (UAE) of phenolic compounds from C. rhizoma. Caffeic acid (CA), isoferulic acid (IA), ferulic acid (FA), and total phenols were quantified by high-performance liquid chromatography-diode array detection and ultraviolet-visible spectrophotometer. Effects of several exper...

  1. Ultrasound-Assisted Extraction of Total Phenolic Compounds from Inula helenium

    Jin Wang; Yong-Ming Zhao; Ya-Ting Tian; Chun-Lin Yan; Chun-Yan Guo

    2013-01-01

    Ultrasound-assisted extraction (UAE) of phenolic compounds from Inula helenium was studied. Effects of ethanol concentration, ultrasonic time, solid-liquid ratio, and number of extractions were investigated. An orthogonal array was constructed to optimize UAE process. The optimized extraction conditions were as follows: ethanol concentration, 30%; solid-liquid ratio, 1 : 20; number of extractions, 2 times; extraction time, 30 min. Under the optimal conditions, the yield of total phenolic comp...

  2. Performance Evaluation of a Synthetic Aperture Real-Time Ultrasound System

    Stuart, Matthias Bo; Tomov, Borislav Gueorguiev; Jensen, Jørgen Arendt

    2011-01-01

    arrays (FPGAs) making it very flexible and allowing implementation of other real-time ultrasound processing methods in the future. For conventional B-mode imaging, a penetration depth around 7 cm for a 7 MHz transducer is obtained (signal-tonoise ratio of 0 dB), which is comparable to commercial...... different channels (on average 111 ps for a 70 MHz sampling clock) are deterministic and can therefore be compensated for....

  3. Design and Implementation of High Frequency Ultrasound Pulsed-Wave Doppler Using FPGA

    Hu, Chang-Hong; Zhou, Qifa; Shung, K. Kirk

    2008-01-01

    The development of a field-programmable gate array (FPGA)-based pulsed-wave Doppler processing approach in pure digital domain is reported in this paper. After the ultrasound signals are digitized, directional Doppler frequency shifts are obtained with a digital-down converter followed by a low-pass filter. A Doppler spectrum is then calculated using the complex fast Fourier transform core inside the FPGA. In this approach, a pulsed-wave Doppler implementation core with reconfigurable and rea...

  4. Super phase array

    Wee, W H; Pendry, J B [Condensed Matter Theory Group Department of Physics Imperial College London London SW7 2AZ (United Kingdom)], E-mail: w.wee07@imperial.ac.uk

    2010-03-15

    For a long time phase arrays have been used in a variety of wave transmission applications because of their simplicity and versatility. Conventionally there is a trade-off between the compactness of a phase array and its directivity. In this paper we demonstrate how by embedding a normal phase array within a superlens (made of negative refractive index material) we can overcome this constraint and create compact phase arrays with a virtual extent much larger than the physical size of the array. In this paper we also briefly discuss the apparent unphysical field divergences in superlenses and how to resolve this issue.

  5. Super phase array

    For a long time phase arrays have been used in a variety of wave transmission applications because of their simplicity and versatility. Conventionally there is a trade-off between the compactness of a phase array and its directivity. In this paper we demonstrate how by embedding a normal phase array within a superlens (made of negative refractive index material) we can overcome this constraint and create compact phase arrays with a virtual extent much larger than the physical size of the array. In this paper we also briefly discuss the apparent unphysical field divergences in superlenses and how to resolve this issue.

  6. Soleus muscle injury: sensitivity of ultrasound patterns

    Balius, Ramon [Sport Catalan Council, Generalitat de Catalunya, Barcelona (Spain); Clinica CMI Diagonal, Barcelona (Spain); Rodas, Gil [F.C. Barcelona Medical Services, Barcelona (Spain); Pedret, Carles [Clinica CMI Diagonal, Barcelona (Spain); Clinica Mapfre de Medicina del Tenis, Sports Medicine and Imaging Department, Barcelona (Spain); Centre de Diagnostic per Imatge de Tarragona, Tarragona (Spain); Capdevila, Lluis [Universitat Autonoma de Barcelona, Laboratory of Sport Psychology, Barcelona (Spain); Alomar, Xavier [Clinica Creu Blanca, Barcelona (Spain); Bong, David A. [Instituto Poal de Reumatologia, Barcelona (Spain)

    2014-06-15

    To assess the sensitivity of ultrasound in detecting soleus muscle lesions diagnosed on magnetic resonance imaging (MRI) and to characterize their location, ultrasound pattern, and evolution. Ultrasound and MRI studies were performed between May 2009 and February 2013 on all patients who presented to the Medical Services Clinic of the Catalan Sport Council with the initial onset of sharp pain in the calf compatible with injury of the soleus muscle. An inter-observer ultrasound reliability study was also performed. A total of 55 cases of soleus injury were studied prospectively (22 with right leg involvement, 33 left) by ultrasound and MRI, which was utilized as the ''gold standard.'' In MRI studies, 24 cases (43.7 %) had myofascial injuries that were localized in the posterior aponeurosis (PMF) in 15 cases (27.3 %) and in the anterior aponeurosis (AMF) in 9 (16.4 %). Thirty-one cases (56.3 %) were musculotendinous injuries, with 9 cases (16.4 %) in the medial aponeurosis (MMT), 11 cases (20 %) in the lateral aponeurosis (LMT), and 11 cases (20 %) in the central tendon (CMT). In comparison to MRI, ultrasound was able to detect injury to the soleus in 27.2 % of cases. No injuries were detected by ultrasound alone. Posterior myofascial injuries were more likely to be detected by ultrasound than anterior myofascial injuries or all types of musculotendinous injuries. Ultrasound patterns for each type of injury were described. Ultrasound is not a sensitive technique for detecting and assessing soleus traumatic tears compared with MRI, although the sensitivity is enhanced by a thorough anatomically based ultrasound examination. Timing of the ultrasound examination may be of importance. Each type of soleus injury appears to have a characteristic ultrasound pattern based on a defect of connective expansions, the existence of small myofascial filiform collections, and the rarefaction of the fibrillar area. (orig.)

  7. Soleus muscle injury: sensitivity of ultrasound patterns

    To assess the sensitivity of ultrasound in detecting soleus muscle lesions diagnosed on magnetic resonance imaging (MRI) and to characterize their location, ultrasound pattern, and evolution. Ultrasound and MRI studies were performed between May 2009 and February 2013 on all patients who presented to the Medical Services Clinic of the Catalan Sport Council with the initial onset of sharp pain in the calf compatible with injury of the soleus muscle. An inter-observer ultrasound reliability study was also performed. A total of 55 cases of soleus injury were studied prospectively (22 with right leg involvement, 33 left) by ultrasound and MRI, which was utilized as the ''gold standard.'' In MRI studies, 24 cases (43.7 %) had myofascial injuries that were localized in the posterior aponeurosis (PMF) in 15 cases (27.3 %) and in the anterior aponeurosis (AMF) in 9 (16.4 %). Thirty-one cases (56.3 %) were musculotendinous injuries, with 9 cases (16.4 %) in the medial aponeurosis (MMT), 11 cases (20 %) in the lateral aponeurosis (LMT), and 11 cases (20 %) in the central tendon (CMT). In comparison to MRI, ultrasound was able to detect injury to the soleus in 27.2 % of cases. No injuries were detected by ultrasound alone. Posterior myofascial injuries were more likely to be detected by ultrasound than anterior myofascial injuries or all types of musculotendinous injuries. Ultrasound patterns for each type of injury were described. Ultrasound is not a sensitive technique for detecting and assessing soleus traumatic tears compared with MRI, although the sensitivity is enhanced by a thorough anatomically based ultrasound examination. Timing of the ultrasound examination may be of importance. Each type of soleus injury appears to have a characteristic ultrasound pattern based on a defect of connective expansions, the existence of small myofascial filiform collections, and the rarefaction of the fibrillar area. (orig.)

  8. Ultrasound diagnosis of uterine myomas.

    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

  9. A View on Despeckling in Ultrasound Imaging

    S.Kalaivani Narayanan

    2009-09-01

    Full Text Available Ultrasound imaging is a widely used and safe medical diagnostic technique, due to its noninvasive nature, low cost and capability of forming real time imaging. However the usefulness of ultrasound imaging is degraded by the presence of signal dependant noise knownas speckle. The speckle pattern depends on the structure of the image tissue and various imaging parameters. There are two main purposes for speckle reduction in medical ultrasound imaging (1 to improve the human interpretation of ultrasound images (2 despeckling is the preprocessing step for many ultrasound image processing tasks such as segmentation and registration. A number of methods have been proposed for speckle reduction in ultrasoundimaging. While incorporating speckle reduction techniques as an aid for visual diagnosis, it has to keep in mind that certain speckle contains diagnostic information and should be retained. The objective of this paper is to give an overview about types of speckle reduction techniques in ultrasound imaging.

  10. Ultrasound: From Earth to Space

    Law, Jennifer; Macbeth, Paul. B.

    2011-01-01

    Ultrasonography is a versatile imaging modality that offers many advantages over radiography, computed tomography, and magnetic resonance imaging. On Earth, the use of ultrasound has become standard in many areas of medicine including diagnosis of medical and surgical diseases, management of obstetric and gynecologic conditions, assessment of critically ill patients, and procedural guidance. Advances in telecommunications have enabled remotely-guided ultrasonography for both geographically is...

  11. Ultrasound Current Source Density Imaging

    Olafsson, Ragnar; Witte, Russell S.; Huang, Sheng-Wen; O’Donnell, Matthew

    2008-01-01

    Surgery to correct severe heart arrhythmias usually requires detailed maps of the cardiac activation wave prior to ablation. The pinpoint electrical mapping procedure is laborious and limited by its spatial resolution (5–10 mm). We propose ultrasound current source density imaging (UCSDI), a direct 3-D imaging technique that potentially facilitates existing mapping procedures with superior spatial resolution. The technique is based on a pressure-induced change in resistivity known as the acou...

  12. Three-dimensional obstetric ultrasound.

    Tache, Veronique; Tarsa, Maryam; Romine, Lorene; Pretorius, Dolores H

    2008-04-01

    Three-dimensional ultrasound has gained a significant popularity in obstetrical practice in recent years. The advantage of this modality in some cases is in question, however. This article provides a basic review of volume acquisition, mechanical positioning, and display modalities. Multiple uses of this technique in obstetrical care including first trimester applications and its utility in clarification of fetal anatomy such as brain, face, heart, and skeleton is discussed. PMID:18450140

  13. Digital beamforming in ultrasound imaging

    1994-01-01

    In medical ultrasound imaging, beam control methods such as dynamic focusing, and dynamic aperture and weighting give a need for more flexible control over the receive beam. In addition the desire to increase acquired framerate makes it a requirement to be able to receive several beams in parallel for each transmitted beam. Digital beamforming implemented with custom VLSI chips will give these capabilities. This paper therefore discusses various concepts for digital beamforming and also gives...

  14. Ultrasound-Intensified Mineral Carbonation

    Santos, Rafael; François, Davy; Mertens, Gilles; Elsen, Jan; Van Gerven, Tom

    2013-01-01

    Several aspects of ultrasound-assisted mineral carbonation were investigated in this work. The objectives were to intensify the CO2 sequestration process to improve reaction kinetics and maximal conversion. Stainless steel slags, derived from the Argon Oxygen Decarburization (AOD) and Continuous Casting / Ladle Metallurgy (CC/LM) refining steps, were used for assessing the technical feasibility of this concept, as they are potential carbon sinks and can benefit from reduction in alkalinity (p...

  15. Ultrasound evaluation of penile fractures

    Kachewar, SG; Kulkarni, DS

    2011-01-01

    This short case report discusses the various aspects of penile fracture, which is a rare entity. Nevertheless, the incidence of penile fractures is on the rise due to the increased use of performance-enhancing drugs. An individual with a penile fracture should seek immediate medical referral. Prompt diagnosis and management is necessary to prevent undesirable after-effects as discussed. Emphasis is made on how imaging with ultrasound enables a quick and complete assessment of this mishap.

  16. Integrated endoscope for real-time 3D ultrasound imaging and hyperthermia: feasibility study.

    Pua, Eric C; Qiu, Yupeng; Smith, S W

    2007-01-01

    The goal of this research is to determine the feasibility of using a single endoscopic probe for the combined purpose of real-time 3D (RT3D) ultrasound imaging of a target organ and the delivery of ultrasound therapy to facilitate the absorption of compounds for cancer treatment. Recent research in ultrasound therapy has shown that ultrasound-mediated drug delivery improves absorption of treatments for prostate, cervical and esophageal cancer. The ability to combine ultrasound hyperthermia and 3D imaging could improve visualization and targeting of cancerous tissues. In this study, numerical modeling and experimental measurements were developed to determine the feasibility of combined therapy and imaging with a 1 cm diameter endoscopic RT3D probe with 504 transmitters and 252 receive channels. This device operates at 5 MHz and has a 6.3 mm x 6.3 mm aperture to produce real time 3D pyramidal scans of 60-120 degrees incorporating 64 x 64 = 4096 image lines at 30 volumes/sec interleaved with a 3D steerable therapy beam. A finite-element mesh was constructed with over 128,000 elements in LS-DYNA to simulate the induced temperature rise from our transducer with a 3 cm deep focus in tissue. Quarter-symmetry of the transducer was used to reduce mesh size and computation time. Based on intensity values calculated in Field II using the transducer's array geometry, a minimum I(SPTA) of 3.6 W/cm2 is required from our endoscope probe in order to induce a temperature rise of 4 degrees C within five minutes. Experimental measurements of the array's power output capabilities were conducted using a PVDF hydrophone placed 3 cm away from the face of the transducer in a watertank. Using a PDA14 Signatec data acquisition board to capture full volumes of transmitted ultrasound data, it was determined that the probe can presently maintain intensity values up to 2.4 W/cm2 over indefinite times for therapeutic applications combined with intermittent 3D scanning to maintain targeting

  17. Venous catheterization with ultrasound navigation

    Kasatkin, A. A., E-mail: ant-kasatkin@yandex.ru; Nigmatullina, A. R. [Izhevsk State Medical Academy, Kommunarov street, 281, Izhevsk, Russia, 426034 (Russian Federation); Urakov, A. L., E-mail: ant-kasatkin@yandex.ru [Institute of Mechanics Ural Branch of Russian Academy of Sciences, T.Baramzinoy street 34, Izhevsk, Russia, 426067, Izhevsk (Russian Federation); Izhevsk State Medical Academy, Kommunarov street, 281, Izhevsk, Russia, 426034 (Russian Federation)

    2015-11-17

    By ultrasound scanning it was determined that respiratory movements made by chest of healthy and sick person are accompanied by respiratory chest rise of internal jugular veins. During the exhalation of an individual diameter of his veins increases and during the breath it decreases down to the complete disappearing if their lumen. Change of the diameter of internal jugular veins in different phases can influence significantly the results of vein puncture and cauterization in patients. The purpose of this research is development of the method increasing the efficiency and safety of cannulation of internal jugular veins by the ultrasound visualization. We suggested the method of catheterization of internal jugular veins by the ultrasound navigation during the execution of which the puncture of venous wall by puncture needle and the following conduction of J-guide is carried out at the moment of patient’s exhalation. This method decreases the risk of complications development during catheterization of internal jugular vein due to exclusion of perforating wound of vein and subjacent tissues and anatomical structures.

  18. Venous catheterization with ultrasound navigation

    Kasatkin, A. A.; Urakov, A. L.; Nigmatullina, A. R.

    2015-11-01

    By ultrasound scanning it was determined that respiratory movements made by chest of healthy and sick person are accompanied by respiratory chest rise of internal jugular veins. During the exhalation of an individual diameter of his veins increases and during the breath it decreases down to the complete disappearing if their lumen. Change of the diameter of internal jugular veins in different phases can influence significantly the results of vein puncture and cauterization in patients. The purpose of this research is development of the method increasing the efficiency and safety of cannulation of internal jugular veins by the ultrasound visualization. We suggested the method of catheterization of internal jugular veins by the ultrasound navigation during the execution of which the puncture of venous wall by puncture needle and the following conduction of J-guide is carried out at the moment of patient's exhalation. This method decreases the risk of complications development during catheterization of internal jugular vein due to exclusion of perforating wound of vein and subjacent tissues and anatomical structures.

  19. Micromachining techniques in developing high-frequency piezoelectric composite ultrasonic array transducers.

    Liu, Changgeng; Djuth, Frank T; Zhou, Qifa; Shung, K Kirk

    2013-12-01

    Several micromachining techniques for the fabrication of high-frequency piezoelectric composite ultrasonic array transducers are described in this paper. A variety of different techniques are used in patterning the active piezoelectric material, attaching backing material to the transducer, and assembling an electronic interconnection board for transmission and reception from the array. To establish the feasibility of the process flow, a hybrid test ultrasound array transducer consisting of a 2-D array having an 8 × 8 element pattern and a 5-element annular array was designed, fabricated, and assessed. The arrays are designed for a center frequency of ~60 MHz. The 2-D array elements are 105 × 105 μm in size with 5-μm kerfs between elements. The annular array surrounds the square 2-D array and provides the option of transmitting from the annular array and receiving with the 2-D array. Each annular array element has an area of 0.71 mm(2) with a 16-μm kerf between elements. The active piezoelectric material is (1 - x) Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT)/epoxy 1-3 composite with a PMN-PT pillar lateral dimension of 8 μm and an average gap width of ~4 μm, which was produced by deep reactive ion etching (DRIE) dry etching techniques. A novel electric interconnection strategy for high-density, small-size array elements was proposed. After assembly, the array transducer was tested and characterized. The capacitance, pulse-echo responses, and crosstalk were measured for each array element. The desired center frequency of ~60 MHz was achieved and the -6-dB bandwidth of the received signal was ~50%. At the center frequency, the crosstalk between adjacent 2-D array elements was about -33 dB. The techniques described herein can be used to build larger arrays containing smaller elements. PMID:24297027

  20. Kinetic Model of Biodiesel Processing Using Ultrasound

    Bambang Susilo

    2009-01-01

    Ultrasound is predicted to be able to accelerate the chemical reaction, to increase the conversion of plant oil into biodiesel, and to decrease the need of catalyst and energy input. The application of ultrasound for processing of biodiesel and the mathematical model were conducted in this research. The result of the experiments showed that the ultrasound increased reaction rate and the conversion of palm oil into biodiesel up to 100%. It was better than the process with mechanical stirrer th...

  1. Colour Doppler ultrasound of the penis

    Wilkins, C.J.; Sriprasad, S.; Sidhu, P.S. E-mail: paulsidhu@compuserve.com

    2003-07-01

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

  2. Contrast enhanced ultrasound of breast cancer

    Cassano, E; Rizzo, S; Bozzini, A; S. Menna; Bellomi, M

    2006-01-01

    The importance of ultrasound examination in the diagnosis of breast cancer has been widely demonstrated. During the last few years, the introduction of ultrasound contrast media has been considered a promising tool for studying the vascular pattern of focal lesions within the breast. Our purpose was to assess whether contrast-enhanced (CE) ultrasound examination, performed using specific contrast imaging modes, can be helpful for detection and characterization of breast lesions, and for predi...

  3. Colour Doppler ultrasound of the penis

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

  4. A View on Despeckling in Ultrasound Imaging

    S.Kalaivani Narayanan; R.S.D.Wahidabanu

    2009-01-01

    Ultrasound imaging is a widely used and safe medical diagnostic technique, due to its noninvasive nature, low cost and capability of forming real time imaging. However the usefulness of ultrasound imaging is degraded by the presence of signal dependant noise knownas speckle. The speckle pattern depends on the structure of the image tissue and various imaging parameters. There are two main purposes for speckle reduction in medical ultrasound imaging (1) to improve the human interpretation of u...

  5. Application of ultrasound in periodontics: Part I

    Bains, Vive K.; Mohan, Ranjana; Bains, Rhythm

    2008-01-01

    Ultrasonic is a branch of acoustics concerned with sound vibrations in frequency ranges above audible level. Ultrasound uses the transmission and reflection of acoustic energy. A pulse is propagated and its reflection is received, both by the transducer. For clinical purposes ultrasound is generated by transducers, which converts electrical energy into ultrasonic waves. This is usually achieved by magnetostriction or piezoelectricity. Primary effects of ultrasound are thermal, mechanical (cav...

  6. Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid

    ... Index A-Z Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid An ultrasound-guided thyroid biopsy ... Thyroid? What is Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid? During a fine needle aspiration ...

  7. Ultrasound-assisted dealumination of zeolite Y

    M Hosseini; M A Zanjanchi; B Ghalami-Choobar; H Golmojdeh

    2015-01-01

    We demonstrate a new procedure for dealumination of zeolite Y. The method employs a 28 KHz ultrasound bath and an ethanolic acetylacetone solution. Acetylacetone was used as chelating agent and ultrasound irradiation was used as extraction intensifier. Four types of samples, as-synthesized, ammoniumexchanged, acidic and neutralized zeolite were used for dealumination. Parts of the framework aluminumatoms are removed from their sites in the structure of zeolite Y upon the use of either acetylacetone on its own or simultaneous use of acetylacetone and ultrasound waves. Higher dealumination was observed for those samples subjected to both ultrasound irradiation and acetylacetone extraction.

  8. Evaluation of spinal ultrasound in spinal dysraphism

    AIMS: The aims of this study were to evaluate the role of spinal ultrasound in detecting occult spinal dysraphism (OSD) in neonates and infants, and to determine the degree of agreement between ultrasound and magnetic resonance imaging (MRI) findings. MATERIALS AND METHODS: Eighty-five consecutive infants had spinal ultrasound over 31 months. Of these, 15 patients (age 1 day-7 months, mean 40 days; nine male) had follow-up MRI. Ultrasound and MRI findings were correlated retrospectively. RESULTS: Six out of 15 (40%) ultrasound examinations showed full agreement with MRI, seven of 15 (47%) had partial agreement, and two of 15 (13%) had no agreement. In the present series ultrasound failed to visualize: four of four dorsal dermal sinuses, three of four fatty filum terminales, one of one terminal lipoma, two of four partial sacral agenesis, three of four hydromyelia and one of 10 low-lying cords. CONCLUSION: Agreement between ultrasound and MRI was good, particularly for the detection of low-lying cord (90%). Therefore we recommend ultrasound as a first-line screening test for OSD. If ultrasound is abnormal, equivocal or technically limited, MRI is advised for full assessment

  9. Evaluation of spinal ultrasound in spinal dysraphism

    Hughes, J.A.; Bruyn, R. de; Patel, K.; Thompson, D

    2003-03-01

    AIMS: The aims of this study were to evaluate the role of spinal ultrasound in detecting occult spinal dysraphism (OSD) in neonates and infants, and to determine the degree of agreement between ultrasound and magnetic resonance imaging (MRI) findings. MATERIALS AND METHODS: Eighty-five consecutive infants had spinal ultrasound over 31 months. Of these, 15 patients (age 1 day-7 months, mean 40 days; nine male) had follow-up MRI. Ultrasound and MRI findings were correlated retrospectively. RESULTS: Six out of 15 (40%) ultrasound examinations showed full agreement with MRI, seven of 15 (47%) had partial agreement, and two of 15 (13%) had no agreement. In the present series ultrasound failed to visualize: four of four dorsal dermal sinuses, three of four fatty filum terminales, one of one terminal lipoma, two of four partial sacral agenesis, three of four hydromyelia and one of 10 low-lying cords. CONCLUSION: Agreement between ultrasound and MRI was good, particularly for the detection of low-lying cord (90%). Therefore we recommend ultrasound as a first-line screening test for OSD. If ultrasound is abnormal, equivocal or technically limited, MRI is advised for full assessment.

  10. Ultrasound-intensified mineral carbonation

    Several aspects of ultrasound-assisted mineral carbonation were investigated in this work. The objectives were to intensify the CO2 sequestration process to improve reaction kinetics and maximal conversion. Stainless steel slags, derived from the Argon Oxygen Decarburization (AOD) and Continuous Casting/Ladle Metallurgy (CC/LM) refining steps, were used for assessing the technical feasibility of this concept, as they are potential carbon sinks and can benefit from reduction in alkalinity (pH) by mineral carbonation. Ultrasound was applied by use of an ultrasound horn into the reaction slurry, where mineral carbonation reaction took place at 50 °C for up to 4 h; comparison was made to solely mechanically mixed process. It was found that sonication increases the reaction rate after the initial stage, and permits achieving higher carbonate conversion and lower pH. AOD slag conversion increased from 30% to 49%, and pH decreased from 10.6 to 10.1; CC slag conversion increased from 61% to 73% and pH decreased from 10.8 to 9.9. The enhancement effect of ultrasound was attributed to the removal of passivating layers (precipitated calcium carbonate and depleted silica) that surround the unreacted particle core and inhibit mass transfer. Significant particle size reduction was observed for sonicated powders, compared to particle size growth in the case of stirring-only; D[4,3] values increased without sonication by 74% and 50%, and decreased with sonication by 64% and 52%, respectively for AOD and CC slags. Considerations on scale-up of this technology, particularly with regards to energy efficiency, are also discussed. Highlights: ► Ultrasound increased CaO, AOD and CC slags mineral carbonation rates and conversions. ► Enhancement effect linked to removal of mass transfer inhibiting passivating layers. ►Carbonated particle size grew with stirring-only, and decreased with sonication. ► Lower pH of slags with greater carbonation extent can reduce heavy metal leaching

  11. Ultrasound techniques in the evaluation of the mediastinum, part I

    Dietrich, Christoph Frank; Annema, Jouke Tabe; Clementsen, Paul;

    2015-01-01

    Ultrasound imaging has gained importance in pulmonary medicine over the last decades including conventional transcutaneous ultrasound (TUS), endoscopic ultrasound (EUS), and endobronchial ultrasound (EBUS). Mediastinal lymph node staging affects the management of patients with both operable and...... staging of lung cancer. A specific emphasis will be on learning mediastinal endosonography. Part I is dealing with an introduction into ultrasound techniques, mediastinal lymph node anatomy and diagnostic reach of ultrasound techniques and part II with the clinical work up of neoplastic and inflammatory...

  12. Carbon nanotube nanoelectrode arrays

    Ren, Zhifeng; Lin, Yuehe; Yantasee, Wassana; Liu, Guodong; Lu, Fang; Tu, Yi

    2008-11-18

    The present invention relates to microelectode arrays (MEAs), and more particularly to carbon nanotube nanoelectrode arrays (CNT-NEAs) for chemical and biological sensing, and methods of use. A nanoelectrode array includes a carbon nanotube material comprising an array of substantially linear carbon nanotubes each having a proximal end and a distal end, the proximal end of the carbon nanotubes are attached to a catalyst substrate material so as to form the array with a pre-determined site density, wherein the carbon nanotubes are aligned with respect to one another within the array; an electrically insulating layer on the surface of the carbon nanotube material, whereby the distal end of the carbon nanotubes extend beyond the electrically insulating layer; a second adhesive electrically insulating layer on the surface of the electrically insulating layer, whereby the distal end of the carbon nanotubes extend beyond the second adhesive electrically insulating layer; and a metal wire attached to the catalyst substrate material.

  13. Pulse-Echo Phased Array Ultrasonic Inspection of Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS)

    Johnston, Pat H.

    2010-01-01

    A PRSEUS test article was subjected to controlled impact on the skin face followed by static and cyclic axial compressions. Phased array ultrasonic inspection was conducted before impact, and after each of the test conditions. A linear phased array probe with a manual X-Y scanner was used for interrogation. Ultrasound showed a delamination between the skin and stringer flange adjacent to the impact. As designed, the stitching in the flange arrested the lateral flaw formation. Subsequent ultrasonic data showed no delamination growth due to continued loading. Keywords: Phased Array, Ultrasonics, Composites, Out-of-Autoclave

  14. Spatial and Temporal Controlled Tissue Heating on a Modified Clinical Ultrasound Scanner for Generating Mild Hyperthermia in Tumors

    Kruse, Dustin E.; Lai, Chun-Yen; Stephens, Douglas N.; Sutcliffe, Patrick; Paoli, Eric E.; Barnes, Stephen H.; Ferrara, Katherine W.

    2010-01-01

    A new system is presented for generating controlled tissue heating with a clinical ultrasound scanner, and initial in vitro and in vivo results are presented that demonstrate both transient and sustained heating in the mild-hyperthermia range of 37–42ºC. The system consists of a Siemens Antares™ ultrasound scanner, a custom dual-frequency 3-row transducer array and an external temperature feedback control system. The transducer has 2 outer rows that operate at 1.5 MHz for tissue heating and a...

  15. Minimum training requirement in ultrasound imaging of peripheral arterial disease

    Eiberg, J P; Hansen, M A; Grønvall Rasmussen, J B;

    2008-01-01

    To demonstrate the minimum training requirement when performing ultrasound of peripheral arterial disease.......To demonstrate the minimum training requirement when performing ultrasound of peripheral arterial disease....

  16. Optimization strategies for ultrasound volume registration

    This paper considers registration of 3D ultrasound volumes acquired in multiple views for display in a single image volume. One way to acquire 3D data is to use a mechanically swept 3D probe. However, the usefulness of these probes is restricted by their limited field of view. This problem can be overcome by attaching a six-degree-of-freedom (DOF) position sensor to the probe, and displaying the information from multiple sweeps in their proper positions. However, an external six-DOF position sensor can be an inconvenience in a clinical setting. The objective of this paper is to propose a hybrid strategy that replaces the sensor with a combination of three-DOF image registration and an unobtrusive inertial sensor for measuring orientation. We examine a range of optimization algorithms and similarity measures for registration and compare them in in vitro and in vivo experiments. We register based on multiple reslice images rather than a whole voxel array. In this paper, we use a large number of reslices for improved reliability at the expense of computational speed. We have found that the Levenberg–Marquardt method is very fast but is not guaranteed to give the correct solution all the time. We conclude that normalized mutual information used in the Nelder–Mead simplex algorithm is potentially suitable for the registration task with an average execution time of around 5 min, in the majority of cases, with two restarts in a C++ implementation on a 3.0 GHz Intel Core 2 Duo CPU machine

  17. Singulation for imaging ring arrays of capacitive micromachined ultrasonic transducers

    Singulation of MEMS is a critical step in the transition from wafer-level to die-level devices. As is the case for capacitive micromachined ultrasound transducer (CMUT) ring arrays, an ideal singulation must protect the fragile membranes from the processing environment while maintaining a ring array geometry. The singulation process presented in this paper involves bonding a trench-patterned CMUT wafer onto a support wafer, deep reactive ion etching (DRIE) of the trenches, separating the CMUT wafer from the support wafer and de-tethering the CMUT device from the CMUT wafer. The CMUT arrays fabricated and singulated in this process were ring-shaped arrays, with inner and outer diameters of 5 mm and 10 mm, respectively. The fabricated CMUT ring arrays demonstrate the ability of this method to successfully and safely singulate the ring arrays and is applicable to any arbitrary 2D shaped MEMS device with uspended microstructures, taking advantage of the inherent planar attributes of DRIE. (technical note)

  18. Measurement of Angle of Ultrasound Propagation from Phase

    Civale, John; Rivens, Ian; Haar, Gail ter, E-mail: john.civale@icr.ac.uk [Joint Department of Physics, The Royal Marsden Hospital, Institute of Cancer Research, Downs Road, Sutton, Surrey, SM2 5PT (United Kingdom)

    2011-02-01

    Acoustic field calibrations often use Fast Fourier Transforms (FFT) to quantify the spectral amplitude components of detected acoustic waveforms. The ability of FFTs to provide phase information is often overlooked. This phase data may be useful in determining the angle of propagation of the ultrasound beam. The angle of propagation at the focal peak (and any other point in the field) can be calculated easily and quickly without additional measurement, and may be the quickest and most accurate method of aligning the sound axis with respect to the beamplotting system's co-ordinates. Acoustic fields have been measured experimentally using a system capable of waveform acquisition. Measurements were made using a fibre-optic hydrophone (Precision Acoustics, UK) which provided spatial resolution of <100 {mu}m. Two operating configurations of a 10 strip array HIFU (high intensity focused ultrasound) transducer were tested, as was a single element HIFU device. Theoretical pressure and phase distributions for these transducers were predicted using a linear acoustic field model. Results show that for the single element, radially symmetric device, beam alignment measurements using phase data at the focal peak are in agreement with the more conventional method based on finding the on-axis peak positions. In the case of a transducer with a number of elements de-activated to produce an asymmetric ultrasound source, the angle of propagation at the focal peak was altered, indicating a change in performance of the transducer which otherwise might not have been detected using the 'on-axis peaks' method. Simulations agreed with the experimental data.

  19. Dual-plane ultrasound flow measurements in liquid metals

    An ultrasound measurement system for dual-plane, two-component flow velocity measurements especially in opaque liquids is presented. Present-day techniques for measuring local flow structures in opaque liquids disclose considerable drawbacks concerning line-wise measurement of single ultrasound probes. For studying time-varying flow patterns, conventional ultrasound techniques are either limited by time-consuming mechanical traversing or by the sequential operation of single probes. The measurement system presented within this paper employs four transducer arrays with a total of 100 single elements which allows for flow mapping without mechanical traversing. A high frame rate of several 10 Hz has been achieved due to an efficient parallelization scheme using time-division multiplexing realized by a microcontroller-based electronic switching matrix. The functionality and capability of the measurement system are demonstrated on a liquid metal flow at room temperature inside a cube driven by a rotating magnetic field (RMF). For the first time, the primary and the secondary flow have been studied in detail and simultaneously using a configuration with two crossed measurement planes. The experimental data confirm predictions made by numeric simulation. After a sudden switching on of the RMF, inertial oscillations of the secondary flow were observed by means of a time-resolved measurement with a frame rate of 3.4 Hz. The experiments demonstrate that the presented measurement system is able to investigate complex and transient flow structures in opaque liquids. Due to its ability to study the temporal evolution of local flow structures, the measurement system could provide considerable progress for fluid dynamics research, in particular for applications in the food industry or liquid metal technologies. (paper)

  20. Ultrasound settings significantly alter arterial lumen and wall thickness measurements

    Green Daniel J

    2008-01-01

    Full Text Available Abstract Background Flow-mediated dilation (FMD and carotid intima-medial thickness (CIMT, measured by ultrasound, are widely used to test the efficacy of cardioprotective interventions. Although assessment methods vary, automated edge-detecting image analysis software is routinely used to measure changes in FMD and CIMT. We aimed to quantify the effect that commonly adjusted ultrasound settings have on arterial lumen and wall thickness measurements made with CIMT measurement software. Methods We constructed phantom arteries from a tissue-mimicking agar compound and scanned them in a water bath with a 10 MHz multi-frequency linear-array probe attached to a high-resolution ultrasound machine. B-mode images of the phantoms were recorded with dynamic range (DR and gain set at five decibel (dB increments from 40 dB to 60 dB and -10 dB to +10 dB respectively. Lumen diameter and wall-thickness were measured off-line using CIMT measurement software. Results Lumen measurements: there was a strong linear relationship between DR and gain and measured lumen diameter. For a given gain level, a 5 dB increase in DR reduced the measured lumen diameter by 0.02 ± 0.004 mm (p CIMT measurements: For a fixed gain level, a 5 dB increase in DR increased measured wall thickness by 0.003 ± 0.002 mm (p Conclusion DR, gain and probe distance significantly alter lumen diameter and CIMT measurements made using image analysis software. When CIMT and FMD are used to test the efficacy of cardioprotective interventions, the DR, gain and probe position used to record baseline scans should be documented and replicated in post-treatment scans in individual trial subjects. If more than one sonographer or imaging centre is used to collect data, the study protocol should document specific DR and gain settings to be used in all subjects.

  1. Hot topics in biomedical ultrasound: ultrasound therapy and its integration with ultrasonic imaging

    Everbach, E. Carr

    2005-09-01

    Since the development of biomedical ultrasound imaging from sonar after WWII, there has been a clear divide between ultrasonic imaging and ultrasound therapy. While imaging techniques are designed to cause as little change as possible in the tissues through which ultrasound propagates, ultrasound therapy typically relies upon heating or acoustic cavitation to produce a desirable therapeutic effect. Concerns over the increasingly high acoustic outputs of diagnostic ultrasound scanners prompted the adoption of the Mechanical Index (MI) and Thermal Index (TI) in the early 1990s. Therapeutic applications of ultrasound, meanwhile, have evolved from deep tissue heating in sports medicine to include targeted drug delivery, tumor and plaque ablation, cauterization via high intensity focused ultrasound (HIFU), and accelerated dissolution of blood clots. The integration of ultrasonic imaging and therapy in one device is just beginning, but the promise of improved patient outcomes is balanced by regulatory and practical impediments.

  2. Ultrasound contrast agents: An overview

    Cosgrove, David [Imaging Sciences Department, Imperial College, Hammersmith Hospital, London (United Kingdom)]. E-mail: d.cosgrove@csc.mrc.ac.uk

    2006-12-15

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

  3. Duplex Doppler ultrasound study of the temporomandibular joint

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

    2012-01-01

    Introduction The anatomy and physiology of the temporomandibular joint can be studied clinically and by diagnostic imaging. Magnetic resonance imaging (MRI), radiography (X-ray) and computed tomography (CT) have thus for many years contributed to the study of the kinetics in the mandibular condyle. However, also duplex Doppler ultrasound (US) examination is widely used in the study of structures during movement, particularly vascular structures. Materials and methods A total of 30 patients were referred by the Department of Orthodontics to the Department of Radiological, Oncological and Pathological Sciences, University of Rome “La Sapienza”. All patients underwent duplex Doppler ultrasound (US) examination of the temporomandibular joint using Toshiba APLIO SSA-770A equipment and duplex Doppler multi-display technique, which allows simultaneous display of US images and color Doppler signals. A linear phased array probe with crystal elements was used operating at a basic frequency of 6 MHz during pulsed Doppler spectral analysis and 7.5 MHz during US imaging. Results In normal patients a regular alternation in the spectral Doppler waveforms was obtained, while in patients with temporomandibular joint meniscus dysfunction there was no regularity in the sum of the Fourier series with an unsteady waveform pattern related to irregular movements of the temporomandibular joint. Conclusions In all cases duplex Doppler US examination proved able to differentiate between normal and pathological patients and among the latter this technique permitted identification of the most significant aspects of the dysfunctional diseases. PMID:23397016

  4. Laparoscopic Ultrasound-Guided Radiofrequency Ablation of Uterine Fibroids

    Four patients with symptomatic uterine fibroids measuring less than 6 cm underwent laparoscopic ultrasound-guided radiofrequency ablation (RFA) using multiprobe-array electrodes. Follow-up of the treated fibroids was performed with gadolinium-enhanced magnetic resonance imaging (MRI) and patients' symptoms were assessed by telephone interviews. The procedure was initially technically successful in 3 of the 4 patients and MRI studies at 1 month demonstrated complete fibroid ablation. Symptom improvement, including a decrease in menstrual bleeding and pain, was achieved in 2 patients at 3 months. At 7 months, 1 of these 2 patients experienced symptom worsening which correlated with recurrent fibroid on MRI. The third, initially technically successfully treated patient did not experience any symptom relief after the procedure and was ultimately diagnosed with adenomyosis. Our preliminary results suggest that RFA is a technically feasible treatment for symptomatic uterine fibroids in appropriately selected patients

  5. Linear description of ultrasound imaging systems

    Jensen, Jørgen Arendt

    These notes have been prepared for the international summer school on advanced ultrasound imaging sponsored by The Danish Research Academy. The notes should be read in conjunction with the notes prepared by Anderson and Trahey1. The intended audience is Ph.D. students working in medical ultrasound...

  6. Ultrasound Elastography in Breast Cancer Diagnosis

    Carlsen, J.; Ewertsen, C; Sletting, S;

    2015-01-01

    Ultrasound elastography is an established method for characterization of focal lesions in the breast. Different techniques and analyses of the images may be used for the characterization. This article addresses the use of ultrasound elastography in breast cancer diagnosis. In the first part of the...

  7. Ultrasound demonstration of prenatal renal vein thrombosis

    This case report illustrates the sonographic appearance of such calcifications which to our knowledge have not been described. We observed abnormalities on a prenatal ultrasound at 37 weeks of gestation and calcifications within the kidney on ultrasound during the neonatal period in an infant of a mother with Class B diabetes mellitus. (orig.)

  8. Synthetic Aperture Imaging in Medical Ultrasound

    Nikolov, Svetoslav; Gammelmark, Kim; Pedersen, Morten;

    2004-01-01

    Synthetic Aperture (SA) ultrasound imaging is a relatively new and unexploited imaging technique. The images are perfectly focused both in transmit and receive, and have a better resolution and higher dynamic range than conventional ultrasound images. The blood flow can be estimated from SA images...

  9. [Lung ultrasound in the newborn].

    Yousef, N

    2016-03-01

    Lung ultrasound (LU) is becoming a bedside point-of-care technique in critical care and emergency medicine as it is performed and immediately interpreted by the clinician. LU is quick, easy, relatively inexpensive, and provides accurate diagnostic information when compared with conventional lung imaging methods, such as CT scans and chest radiographs, with the additional advantage of being non-irradiating, adapted to bedside use, and easily repeatable with no side effects for the patient. LU is easy to learn, does not require sophisticated ultrasound machines or settings, and shows low intra- and interobserver variability when a standardized approach is used. A comprehensive and standardized ultrasound semiology has been described and validated in both adults and children. In summary, LU allows for quick easy recognition of a normally aerated lung in contrast to an interstitial or alveolar pattern. Recognition of these patterns may be even easier in neonates due to their small size and the absence of obesity and heavy musculature. Specific LU findings have been described for some types of neonatal lung injury, such as neonatal respiratory distress syndrome, transient tachypnea of the neonate, meconium aspiration syndrome, and neonatal pneumonia. In the newborn, LU has proved its usefulness in predicting the need for hospital admission and/or intubation based on simple LU patterns. A recently proposed LU score, adapted for the neonate, correlates well with oxygenation status, independently of gestational age and underlying respiratory condition. The score reliably predicts the need for surfactant treatment in preterm babies less than 34 weeks gestation treated with nasal CPAP from birth. LU is a promising tool with numerous potential applications that warrant future studies. However, like every technique, LU has its limitations and should not completely replace standard radiography. LU can nevertheless largely reduce exposure to ionizing radiation by limiting the

  10. ISS Solar Array Management

    Williams, James P.; Martin, Keith D.; Thomas, Justin R.; Caro, Samuel

    2010-01-01

    The International Space Station (ISS) Solar Array Management (SAM) software toolset provides the capabilities necessary to operate a spacecraft with complex solar array constraints. It monitors spacecraft telemetry and provides interpretations of solar array constraint data in an intuitive manner. The toolset provides extensive situational awareness to ensure mission success by analyzing power generation needs, array motion constraints, and structural loading situations. The software suite consists of several components including samCS (constraint set selector), samShadyTimers (array shadowing timers), samWin (visualization GUI), samLock (array motion constraint computation), and samJet (attitude control system configuration selector). It provides high availability and uptime for extended and continuous mission support. It is able to support two-degrees-of-freedom (DOF) array positioning and supports up to ten simultaneous constraints with intuitive 1D and 2D decision support visualizations of constraint data. Display synchronization is enabled across a networked control center and multiple methods for constraint data interpolation are supported. Use of this software toolset increases flight safety, reduces mission support effort, optimizes solar array operation for achieving mission goals, and has run for weeks at a time without issues. The SAM toolset is currently used in ISS real-time mission operations.

  11. Array for detecting microbes

    Andersen, Gary L.; DeSantis, Todd D.

    2014-07-08

    The present embodiments relate to an array system for detecting and identifying biomolecules and organisms. More specifically, the present embodiments relate to an array system comprising a microarray configured to simultaneously detect a plurality of organisms in a sample at a high confidence level.

  12. Nursing ultrasound examination in catheterization

    Luca Romei

    2007-12-01

    Full Text Available Ultrasound (US examination of the bladder can precisely determine the bladder volume and is a useful tool in estimating the residual urine volume. Its application is consequently recommended as an alternative to catheterization for the determination of residual urine. Moreover it represents a simple, noninvasive method to predict the outcome of a voiding trial following acute urine retention based on intravesical prostatic protrusion and on the US pattern of the bladder content. In this article, the Authors review the implementation and results of a bladder US program developed for non-medical caregivers at one Emergency Department.

  13. Testicular neoplasm diagnosed by ultrasound.

    Senay, B A; Stein, B S

    1986-06-01

    The diagnosis of testicular cancer is usually made by the findings of a testicular mass on physical examination. In rare cases a young man will present with retroperitoneal nodes and a normal testicular examination. In such cases a testicular ultrasound may localize the testis which harbors a subclinical neoplasm. In addition serum markers of B-HCG and AFP are essential. As a screening procedure a urine pregnancy test is helpful, since it can be obtained quickly while quantitative B-HCG and APF results are delayed. PMID:3523046

  14. Musculoskeletal Ultrasound in Pediatric Trauma

    A. Shakeri Bavil

    2008-01-01

    Full Text Available Radiographs are the initial diagnostic modality used in evaluation of trauma, but sonography lacks ionizing radiation risks and allows in depth assessment of no ossified joint areas, soft tissues and superficial bone-to-soft tissue interfaces. Regarding the use of sonography to asses soft tissue injuries, the ultrasonographic evaluation of clavicle fractures, proximal humerus epiphysiolysis and fractures of hip has been well standardized."nThe aim of this review is to present the currently applied clinical ultrasound imaging techniques and to provide guidelines for efficient evaluation of musculoskeletal injuries and disorders in children.

  15. Ultrasound in Acute Kidney Disease.

    Meola, Mario; Nalesso, Federico; Petrucci, Ilaria; Samoni, Sara; Ronco, Claudio

    2016-01-01

    Kidneys' imaging provides useful information in acute kidney injury (AKI) diagnosis and management. Today, several imaging techniques give information on kidneys anatomy, urinary obstruction, differential diagnosis between AKI and chronic kidney disease (CKD), renal blood flow and glomerular filtration rate. Ultrasound is a safe, non-invasive and repeatable imaging technique so it is widely used in the first level work-up of AKI. The utility of contrast-enhanced computed tomography and magnetic resonance imaging in AKI or in AKI during CKD is limited because of renal toxicity associated with contrast agents used. PMID:27169556

  16. Micromachined electrode array

    Okandan, Murat (Edgewood, NM); Wessendorf, Kurt O. (Albuquerque, NM)

    2007-12-11

    An electrode array is disclosed which has applications for neural stimulation and sensing. The electrode array, in certain embodiments, can include a plurality of electrodes each of which is flexibly attached to a common substrate using a plurality of springs to allow the electrodes to move independently. In other embodiments of the electrode array, the electrodes can be fixed to the substrate. The electrode array can be formed from a combination of bulk and surface micromachining, and can include electrode tips having an electroplated metal (e.g. platinum, iridium, gold or titanium) or a metal oxide (e.g. iridium oxide) for biocompatibility. The electrode array can be used to form a part of a neural prosthesis, and is particularly well adapted for use in an implantable retinal prosthesis.

  17. Diode Laser Arrays

    Botez, Dan; Scifres, Don R.

    1994-08-01

    This book provides a comprehensive overview of the fundamental principles and applications of semiconductor diode laser arrays. All of the major types of arrays are discussed in detail, including coherent, incoherent, edge- and surface-emitting, horizontal- and vertical-cavity, individually addressed, lattice- matched and strained-layer systems. The initial chapters cover such topics as lasers, amplifiers, external-cavity control, theoretical modeling, and operational dynamics. Spatially incoherent arrays are then described in detail, and the uses of vertical-cavity surface emitter and edge-emitting arrays in parallel optical-signal processing and multi-channel optical recording are discussed. Researchers and graduate students in solid state physics and electrical engineering studying the properties and applications of such arrays will find this book invaluable.

  18. Microfabricated ion trap array

    Blain, Matthew G.; Fleming, James G.

    2006-12-26

    A microfabricated ion trap array, comprising a plurality of ion traps having an inner radius of order one micron, can be fabricated using surface micromachining techniques and materials known to the integrated circuits manufacturing and microelectromechanical systems industries. Micromachining methods enable batch fabrication, reduced manufacturing costs, dimensional and positional precision, and monolithic integration of massive arrays of ion traps with microscale ion generation and detection devices. Massive arraying enables the microscale ion traps to retain the resolution, sensitivity, and mass range advantages necessary for high chemical selectivity. The reduced electrode voltage enables integration of the microfabricated ion trap array with on-chip circuit-based rf operation and detection electronics (i.e., cell phone electronics). Therefore, the full performance advantages of the microfabricated ion trap array can be realized in truly field portable, handheld microanalysis systems.

  19. Applications of ultrasound in food technology

    Zbigniew J. Dolatowski

    2007-09-01

    Full Text Available Ultrasonic is a rapidly growing field of research, which is finding increasing use in the food industry for both the analysis and modification of food products. The sound ranges employed can be divided into high frequency, low energy diagnostic ultrasound and low frequency, high energy power ultrasound. The former is usually used as a non-destructive analytical technique for quality assurance and process control with particular reference to physicochemical properties such as composition, structure and physical state of foods. Nowadays, power ultrasound is considered to be an emerging and promising technology for industrial food processing. The use of ultrasound in processing creates novel and interesting methodologies which are often complementary to classical techniques. Various areas have been identified with great potential for future development: crystallisation, degassing, drying, extraction, filtration, freezing, homogenisation, meat tenderization, sterilization, etc. There is a wide scope for further research into the use of ultrasound in food processing both from an industrial and academic viewpoint.

  20. Application of Ultrasound in Food Drying

    Senem Tüfekçi

    2015-12-01

    Full Text Available Drying has a privileged position in all food preservation methods by reducing of existing water content in food not allowing spoilage, providing a precise and cheap preservation opportunity. Sound waves with frequencies above human hearing are called as ultrasound. Ultrasound which is applied prior to drying as pretreatment or simultaneously is effective on drying performance of products. It is known that diffusion of water increased and total process time shortened in processes that ultrasonic energy is combined with different drying methods and products treated with ultrasound are rehydrated easier. Also ultrasound found to be an alternative method for producing low-sugar dried products. In this study, the basic effect mechanisms of ultrasonic energy and its application fields, effect on drying kinetics and products quality in processes which ultrasound combined with different drying methods such as osmotic drying, hot air drying and freeze drying are examined in the light of studies in literature.

  1. Teaching prenatal ultrasound to family medicine residents.

    Dresang, Lee T; Rodney, William MacMillan; Dees, Jason

    2004-02-01

    Prenatal ultrasound is a powerful diagnostic tool, but there has been little research on how to teach ultrasound to family physicians. The available evidence supports teaching through didactics followed by supervised scanning. Didactic topics include physics and machine usage, indications, fetal biometry, anatomic survey, practice management, ethical issues, and resources. Supervised scanning reinforces the didactic components of training. A "hand-on-hand" supervised scanning technique is recommended for the transmission of psychomotor skills in these sessions. Curricula for teaching ultrasound should include information on which residents will be taught prenatal ultrasound, who will teach them, how to create time for learning ultrasound skills, and how to test for competency. The literature suggests that competency can be achieved within 25-50 supervised scans. Measures of competency include examination and qualitative analysis of scanning. Competency-based testing needs further development because no uniform standards have been established. PMID:14872356

  2. Analog gradient beamformer for a wireless ultrasound scanner

    Di Ianni, Tommaso; Hemmsen, Martin Christian; Bagge, Jan; Jensen, Henrik; Vardi, Nitsan; Jensen, Jørgen Arendt

    2016-04-01

    This paper presents a novel beamformer architecture for a low-cost receiver front-end, and investigates if the image quality can be maintained. The system is oriented to the development of a hand-held wireless ultrasound probe based on Synthetic Aperture Sequential Beamforming, and has the advantage of effectively reducing circuit complexity and power dissipation. The array of transducers is divided into sub-apertures, in which the signals from the single channels are aligned through a network of cascaded gradient delays, and summed in the analog domain before A/D conversion. The delay values are quantized to simplify the shifting unit, and a single A/D converter is needed for each sub-aperture yielding a compact, low-power architecture that can be integrated in a single chip. A simulation study was performed using a 3:75MHz convex array, and the point spread function (PSF) for different configurations was evaluated in terms of lateral full-width-at-half-maximum (FWHM) and -20 dB cystic resolution (CR). Several setups were simulated varying the sub-aperture size N and the quantization step, and design constraints were obtained comparing the PSF to that of an ideal non-quantized system. The PSF is shown for N = 32 with a quantization step of 12 ns. For this configuration, the FWHM is degraded by 0.25% and the CR is 8.70% lower compared to the ideal situation. The results demonstrate that the gradient beamformer provides an adequate image quality, and open the way to a fully-integrated chip for a compact, low-cost, wireless ultrasound probe.

  3. A novel synthetic aperture technique for breast tomography with toroidal arrays

    Huang, Lianjie [Los Alamos National Laboratory; Simonetti, Francesco [IMPERIAL COLLEGE

    2009-01-01

    Ultrasound is commonly used as an adjunct to mammography for diagnostic evaluation of suspicions arising from breast cancer screening. As an alternative to conventional sonography that uses hand-held transducers, toroidal array probes that encircle the breast immersed in a water bath have been investigated for ultrasound tomography. This paper introduces a new method for three-dimensional synthetic aperture diffraction tomography that maximizes the resolution in the scanning direction and provides quantitative reconstructions of the acoustic properties of the object. The method is validated by means of numerical simulations.

  4. A miniature real-time volumetric ultrasound imaging system

    Wygant, Ira O.; Yeh, David T.; Zhuang, Xuefeng; Nikoozadeh, Amin; Oralkan, Omer; Ergun, Arif S.; Karaman, Mustafa; Khuri-Yakub, Butrus T.

    2005-04-01

    Progress made in the development of a miniature real-time volumetric ultrasound imaging system is presented. This system is targeted for use in a 5-mm endoscopic channel and will provide real-time, 30-mm deep, volumetric images. It is being developed as a clinically useful device, to demonstrate a means of integrating the front-end electronics with the transducer array, and to demonstrate the advantages of the capacitive micromachined ultrasonic transducer (CMUT) technology for medical imaging. Presented here is the progress made towards the initial implementation of this system, which is based on a two-dimensional, 16x16 CMUT array. Each CMUT element is 250 um by 250 um and has a 5 MHz center frequency. The elements are connected to bond pads on the back side of the array with 400-um long through-wafer interconnects. The transducer array is flip-chip bonded to a custom-designed integrated circuit that comprises the front-end electronics. The result is that each transducer element is connected to a dedicated pulser and low-noise preamplifier. The pulser generates 25-V, 100-ns wide, unipolar pulses. The preamplifier has an approximate transimpedance gain of 500 kOhm and 3-dB bandwidth of 10 MHz. In the first implementation of the system, one element at a time can be selected for transmit and receive and thus synthetic aperture images can be generated. In future implementations, 16 channels will be active at a given time. These channels will connect to an FPGA-based data acquisition system for real-time image reconstruction.

  5. Quality assurance in diagnostic ultrasound

    Sipilae, Outi, E-mail: outi.sipila@hus.fi [HUS Helsinki Medical Imaging Center, Helsinki University Central Hospital, P.O. Box 340, 00029 HUS (Finland); Mannila, Vilma, E-mail: vilma.mannila@hus.fi [HUS Helsinki Medical Imaging Center, Helsinki University Central Hospital, P.O. Box 340, 00029 HUS (Finland); Department of Physics, University of Helsinki, P.O. Box 64, 00014 Helsinki University (Finland); Vartiainen, Eija, E-mail: eija.vartiainen@hus.fi [HUS Helsinki Medical Imaging Center, Helsinki University Central Hospital, P.O. Box 750, 00029 HUS (Finland)

    2011-11-15

    Objective: To setup a practical ultrasound quality assurance protocol in a large radiological center, results from transducer tests, phantom measurements and visual checks for physical faults were compared. Materials and methods: Altogether 151 transducers from 54 ultrasound scanners, from seven different manufacturers, were tested with a Sonora FirstCall aPerio{sup TM} system (Sonora Medical Systems, Inc., Longmont, CO, USA) to detect non-functional elements. Phantom measurements using a CIRS General Purpose Phantom Model 040 (CIRS Tissue Simulation and Phantom Technology, VA, USA) were available for 135 transducers. The transducers and scanners were also checked visually for physical faults. The percentages of defective findings in these tests were computed. Results: Defective results in the FirstCall tests were found in 17% of the 151 transducers, and in 16% of the 135 transducers. Defective image quality resulted with 15% of the transducers, and 25% of the transducers had a physical flaw. In 16% of the scanners, a physical fault elsewhere than in the transducer was found. Seven percent of the transducers had a concurrent defective result both in the FirstCall test and in the phantom measurements, 8% in the FirstCall test and in the visual check, 4% in the phantom measurements and in the visual check, and 2% in all three tests. Conclusion: The tested methods produced partly complementary results and seemed all to be necessary. Thus a quality assurance protocol is forced to be rather labored, and therefore the benefits and costs must be closely followed.

  6. Quality assurance in diagnostic ultrasound

    Objective: To setup a practical ultrasound quality assurance protocol in a large radiological center, results from transducer tests, phantom measurements and visual checks for physical faults were compared. Materials and methods: Altogether 151 transducers from 54 ultrasound scanners, from seven different manufacturers, were tested with a Sonora FirstCall aPerioTM system (Sonora Medical Systems, Inc., Longmont, CO, USA) to detect non-functional elements. Phantom measurements using a CIRS General Purpose Phantom Model 040 (CIRS Tissue Simulation and Phantom Technology, VA, USA) were available for 135 transducers. The transducers and scanners were also checked visually for physical faults. The percentages of defective findings in these tests were computed. Results: Defective results in the FirstCall tests were found in 17% of the 151 transducers, and in 16% of the 135 transducers. Defective image quality resulted with 15% of the transducers, and 25% of the transducers had a physical flaw. In 16% of the scanners, a physical fault elsewhere than in the transducer was found. Seven percent of the transducers had a concurrent defective result both in the FirstCall test and in the phantom measurements, 8% in the FirstCall test and in the visual check, 4% in the phantom measurements and in the visual check, and 2% in all three tests. Conclusion: The tested methods produced partly complementary results and seemed all to be necessary. Thus a quality assurance protocol is forced to be rather labored, and therefore the benefits and costs must be closely followed.

  7. Pancreatic multicenter ultrasound study (PAMUS)

    Aim: To describe the typical CEUS pattern of pancreatic lesions and to evaluate the diagnostic accuracy of Contrast-enhanced ultrasound (CEUS) in their characterization. Materials and methods: All US and CEUS examinations of focal pancreatic masses performed in six centers during a period of five years were reviewed. Inclusion criteria were: focal pancreatic mass pathologically proved, visible at ultrasound (US) and studied with CEUS. All lesions were then evaluated for size, aspect and enhancement pattern. Sensitivity, specificity, positive and negative predictive values with 95% CIs were calculated to define diagnostic accuracy of CEUS in respect to pathology. Diagnostic confidence of US and CEUS, discerning between benign and malignant lesions, were represented by using ROC (receiver operating characteristics) curves. Agreement was evaluated by means of k statistics. Results: 1439 pancreatic lesions were included. At CEUS the lesions were divided into solid (89%) and cystic (12%) masses and classified into six and eight categories, respectively. Among the solid lesions, adenocarcinomas were characterized with an accuracy of 87.8%. Among the cystic lesions, cystic tumors were diagnosed with an accuracy of 97.1%. ROC curve area increased from 0.637 for US to 0.877 for CEUS (p < 0.0001). Inter-observer agreement was slightly higher for solid (k = 0.78) than cystic (k = 0.62) lesions. In none of the centers side effects were reported. Conclusion: CEUS is accurate in the characterization of pancreatic lesions. CEUS should be considered as a complementary imaging method for pancreatic lesions characterization.

  8. Fast and mechanistic ultrasound simulation using a point source/receiver approach.

    Aguilar, Luis A; Cobbold, Richard S C; Steinman, David A

    2013-11-01

    Ultrasound simulators relying on impulse response methods are faithful to the mechanisms of image formation from the underlying radio-frequency signals, but as a result tend to be relatively slow. At the other extreme are fast techniques, often motivated by the development of teaching and training simulators, which approximate the image formation processes rather than rigorously modeling the underlying physics. Previously, we have shown that transmit field distributions from linear phased-array transducers can be modeled accurately and efficiently using arrays of point sources. This approach is now extended to point sources/receivers, which allows for simulation of the transmit/receive fields, and thus the physical processes underlying ultrasound image formation. Field distributions and fast-time signals are shown to compare favorably to those obtained using the impulse response method. Doppler spectrogram and B-mode images derived from these signals also show excellent agreement with the results obtained using the impulse response method, but with a computational savings of nearly two orders of magnitude. Because of the inherent simplicity of our Fast and Mechanistic Ultrasound Simulation (FAMUS) approach, CPU parallelization was readily achieved, and further orders of magnitude speed improvements, and thus real-time performance, can be anticipated via extension to modern graphics processing units. PMID:24158289

  9. Direct Digital Demultiplexing of Analog TDM Signals for Cable Reduction in Ultrasound Imaging Catheters.

    Carpenter, Thomas M; Rashid, M Wasequr; Ghovanloo, Maysam; Cowell, David M J; Freear, Steven; Degertekin, F Levent

    2016-08-01

    In real-time catheter-based 3-D ultrasound imaging applications, gathering data from the transducer arrays is difficult, as there is a restriction on cable count due to the diameter of the catheter. Although area and power hungry multiplexing circuits integrated at the catheter tip are used in some applications, these are unsuitable for use in small sized catheters for applications, such as intracardiac imaging. Furthermore, the length requirement for catheters and limited power available to on-chip cable drivers leads to limited signal strength at the receiver end. In this paper, an alternative approach using analog time-division multiplexing (TDM) is presented, which addresses the cable restrictions of ultrasound catheters. A novel digital demultiplexing technique is also described, which allows for a reduction in the number of analog signal processing stages required. The TDM and digital demultiplexing schemes are demonstrated for an intracardiac imaging system that would operate in the 4- to 11-MHz range. A TDM integrated circuit (IC) with an 8:1 multiplexer is interfaced with a fast analog-to-digital converter (ADC) through a microcoaxial catheter cable bundle, and processed with a field-programmable gate array register-transfer level simulation. Input signals to the TDM IC are recovered with -40-dB crosstalk between the channels on the same microcoax, showing the feasibility of this system for ultrasound imaging applications. PMID:27116738

  10. The effect of B-mode diagnostic ultrasound exposure on rabbit foetal bone mineral density (BMD)

    Aim: To investigate the changes in rabbit foetal body composition in terms of bone mineral density (BMD) after ultrasound exposure (insonation) was given during different stages of gestation at different lengths of exposure time. Methods: Three groups of pregnant rabbits; A, B, and C were given an ultrasound exposure of 30, 60 and 90 min, respectively; during “Trimester 1”, “Trimester 2”, and “Trimester 3”, using a 2-D B-mode Philips HD3 ultrasound system with a 9 MHz 50 mm broadband high-resolution linear array transducer. A fourth group of pregnant rabbits, O, was used as control. Each full-term newborn rabbits were scanned using a Lunar DPX-IQ dual energy X-ray absorptiometry (DEXA) scanner for whole-body BMD measurement in grams per centimetre square (g/cm2). Results: The results suggested that insonation for 90 min in the 1st and 2nd trimester produced significant increase in BMD of rabbit foetus. Conclusion: This in-vivo study revealed that a 90 min B-mode diagnostic ultrasound exposure during the 1st and the 2nd trimesters caused significant increase in foetal BMD. A further study should be instituted to determine whether this finding in rabbit may also occur in human by means of clinical trials.

  11. Introduction to adaptive arrays

    Monzingo, Bob; Haupt, Randy

    2011-01-01

    This second edition is an extensive modernization of the bestselling introduction to the subject of adaptive array sensor systems. With the number of applications of adaptive array sensor systems growing each year, this look at the principles and fundamental techniques that are critical to these systems is more important than ever before. Introduction to Adaptive Arrays, 2nd Edition is organized as a tutorial, taking the reader by the hand and leading them through the maze of jargon that often surrounds this highly technical subject. It is easy to read and easy to follow as fundamental concept

  12. Simulation of ultrasonic and EMAT arrays using FEM and FDTD.

    Xie, Yuedong; Yin, Wuliang; Liu, Zenghua; Peyton, Anthony

    2016-03-01

    This paper presents a method which combines electromagnetic simulation and ultrasonic simulation to build EMAT array models. For a specific sensor configuration, Lorentz forces are calculated using the finite element method (FEM), which then can feed through to ultrasonic simulations. The propagation of ultrasound waves is numerically simulated using finite-difference time-domain (FDTD) method to describe their propagation within homogenous medium and their scattering phenomenon by cracks. Radiation pattern obtained with Hilbert transform on time domain waveforms is proposed to characterise the sensor in terms of its beam directivity and field distribution along the steering angle. PMID:26596420

  13. Ultrasound

    ... Collaboratives Launch Prematurity research centers What is team science? More than 75 years of solving problems March ... for your patients Medical resources Professional education Awards, scholarships & grants For policy makers Policies & positions State advocacy ...

  14. Ultrasound of the acute abdomen performed by surgeons in training

    Eiberg, J.P.; Grantcharov, T.P.; Eriksen, J.R.;

    2008-01-01

    perform valid abdominal ultrasound examinations of patients referred with acute abdominal pain. METHODS: Patients referred with acute abdominal pain had an ultrasound examination by a surgeon in training as well as by an experienced consultant radiologist whose results served as the gold standard. All...... participating surgeons were without any pre-existing ultrasound experience and received one hour of introduction to abdominal ultrasound. RESULTS: Thirty patients underwent 40 surgeon performed and 30 radiologist performed ultrasound examinations. Regarding gallstone and cholecholecystitis the sensitivity...

  15. Protein Functionalized Nanodiamond Arrays

    Liu YL

    2010-01-01

    Full Text Available Abstract Various nanoscale elements are currently being explored for bio-applications, such as in bio-images, bio-detection, and bio-sensors. Among them, nanodiamonds possess remarkable features such as low bio-cytotoxicity, good optical property in fluorescent and Raman spectra, and good photostability for bio-applications. In this work, we devise techniques to position functionalized nanodiamonds on self-assembled monolayer (SAMs arrays adsorbed on silicon and ITO substrates surface using electron beam lithography techniques. The nanodiamond arrays were functionalized with lysozyme to target a certain biomolecule or protein specifically. The optical properties of the nanodiamond-protein complex arrays were characterized by a high throughput confocal microscope. The synthesized nanodiamond-lysozyme complex arrays were found to still retain their functionality in interacting with E. coli.

  16. Permutations of cubical arrays

    The structure constants of an algebra determine a cube called the cubical array associated with the algebra. The permuted indices of the cubical array associated with a finite semifield generate new division algebras. We do not not require that the algebra be finite and ask 'Is it possible to choose a basis for the algebra such any permutation of the indices of the structure constants leaves the algebra unchanged?' What are the associated algebras? Author shows that the property 'weakly quadratic' is invariant under all permutations of the indices of the corresponding cubical array and presents two algebras for which the cubical array is invariant under all permutations of the indices.

  17. Flexible retinal electrode array

    Okandan, Murat (Albuquerque, NM); Wessendorf, Kurt O. (Albuquerque, NM); Christenson, Todd R. (Albuquerque, NM)

    2006-10-24

    An electrode array which has applications for neural stimulation and sensing. The electrode array can include a large number of electrodes each of which is flexibly attached to a common substrate using a plurality of springs to allow the electrodes to move independently. The electrode array can be formed from a combination of bulk and surface micromachining, with electrode tips that can include an electroplated metal (e.g. platinum, iridium, gold or titanium) or a metal oxide (e.g. iridium oxide) for biocompatibility. The electrode array can be used to form a part of a neural prosthesis, and is particularly well adapted for use in an implantable retinal prosthesis where the electrodes can be tailored to provide a uniform gentle contact pressure with optional sensing of this contact pressure at one or more of the electrodes.

  18. Expandable LED array interconnect

    Yuan, Thomas Cheng-Hsin; Keller, Bernd

    2011-03-01

    A light emitting device that can function as an array element in an expandable array of such devices. The light emitting device comprises a substrate that has a top surface and a plurality of edges. Input and output terminals are mounted to the top surface of the substrate. Both terminals comprise a plurality of contact pads disposed proximate to the edges of the substrate, allowing for easy access to both terminals from multiple edges of the substrate. A lighting element is mounted to the top surface of the substrate. The lighting element is connected between the input and output terminals. The contact pads provide multiple access points to the terminals which allow for greater flexibility in design when the devices are used as array elements in an expandable array.

  19. Fast Computation of Wideband Beam Pattern for Designing Large-Scale 2-D Arrays.

    Chi, Cheng; Li, Zhaohui

    2016-06-01

    For real-time and high-resolution 3-D ultrasound imaging, the design of sparse distribution and weights of elements of a large-scale wideband 2-D array is needed to reduce hardware cost and achieve better directivity. However, due to the high time consumption of computing the wideband beam pattern, the design methods that need massive iterations have rarely been applied to design large-scale wideband 2-D arrays by directly computing the wideband beam pattern. In this paper, a fast method is proposed to realize the computation of a wideband beam pattern of arbitrary 2-D arrays in the far field in order to design large-scale wideband 2-D arrays. The proposed fast method exploits two important techniques: 1) nonuniform fast Fourier transform (FFT) and 2) short inverse FFT. Compared with the commonly used ultrasound simulator Field II, two orders of magnitude improvement in computation speed is achieved with comparable accuracy. The proposed fast method enables massive iterations of direct wideband beam pattern computation of arbitrary large-scale 2-D arrays. A design example in this paper demonstrates that the proposed fast method can help achieve better performance in designing large-scale wideband 2-D arrays. PMID:27046870

  20. Ultrasound Elastography in Breast Cancer Diagnosis.

    Carlsen, J; Ewertsen, C; Sletting, S; Vejborg, I; Schäfer, F K W; Cosgrove, D; Bachmann Nielsen, M

    2015-12-01

    Ultrasound elastography is an established method for characterization of focal lesions in the breast. Different techniques and analyses of the images may be used for the characterization. This article addresses the use of ultrasound elastography in breast cancer diagnosis. In the first part of the article the techniques behind both strain- and shear-wave-elastography are explained and followed by a section on how to obtain adequate elastography images and measurements. In the second part of the article the application of elastography as an adjunct to B-mode ultrasound in clinical practice is described, and the potential diagnostic gains and limitations of elastography are discussed. PMID:26274379

  1. Estimation of blood velocities using ultrasound

    Jensen, Jørgen Arendt

    Ultrasound systems are especially useful in estimating blood velocities in the human body because they are noninvasive and can display an estimate in real time. This book offers a comprehensive treatment of this relatively new, important technology. The book begins with an introduction to...... ultrasound, flow physics, and the circulatory system. Next, the interaction of ultrasound with blood is discussed. The special contribution of the book lies in the remaining chapters, which offer a lucid, thorough description of continuous and pulsed wave systems, the latest systems for doing color flow...

  2. Ultrasound-Targeted Retroviral Gene Delivery

    Taylor, Sarah L.; Rahim, Ahad A.; Bush, Nigel L.; Bamber, Jeffrey C.; Porter, Colin D.

    2007-05-01

    This study demonstrates the ability of focused ultrasound to target retroviral gene delivery. Key to our experiments was the use of non-infectious virus particles lacking the envelope protein required for receptor-mediated entry. The novelty of our approach is that spatial control at a distance is exerted upon viral delivery by subsequent exposure to ultrasound, leading to stable gene delivery. The technology is ideally suited to controlling gene delivery in vivo following systemic vector administration. Our data provide a solution to the critical issue of obtaining tissue specificity with retroviral vectors and impart stability of expression to ultrasound-mediated gene delivery.

  3. Aligators for arrays

    Henzinger, Thomas A.; Hottelier, Thibaud; Kovács, Laura; Rybalchenko, Andrey

    2010-01-01

    This paper presents Aligators, a tool for the generation of universally quantified array invariants. Aligators leverages recurrence solving and algebraic techniques to carry out inductive reasoning over array content. The Aligators’ loop extraction module allows treatment of multi-path loops by exploiting their commutativity and serializability properties. Our experience in applying Aligators on a collection of loops from open source software projects indicates the applicability of recurren...

  4. RFID array sensing

    Capdevila Cascante, Santiago; Jofre Roca, Lluís; Romeu Robert, Jordi; Bolomey, J.Ch

    2010-01-01

    In this paper the use of RFID tags for the measurement of physical parameters in a distributed set of points is presented. Experimental results for two different scenarios are presented; the first uses a 2D RFID array to measure the field distribution of a radiating aperture, while the second detects the change in the close environment of an array of RFID tags to determine the water level of a container.

  5. Microphone arrays fundamentals

    Embrechts, Jean-Jacques

    2011-01-01

    Microphone arrays are essentially directional sensors. They are therefore mainly used for locating, identifying, isolating, measuring and recording individual sound sources. The main principles governing the directivity of microphone arrays are reviewed: phase differences between signals create constructive and destructive interferences, depending on the direction of the sound source. Moreover, signal processing is applied to provide “beamforming”, i.e. beam shaping and steering. Contrary to ...

  6. Doppler ultrasound for diagnosis of soft tissue sarcoma: efficacy of ultrasound-based screening score

    Nagano Satoshi

    2015-06-01

    Full Text Available Background. The utility of ultrasound imaging in the screening of soft-part tumours (SPTs has been reported. We classified SPTs according to their blood flow pattern on Doppler ultrasound and re-evaluated the efficacy of this imaging modality as a screening method. Additionally, we combined Doppler ultrasound with several values to improve the diagnostic efficacy and to establish a new diagnostic tool.

  7. How to learn and to perform endoscopic ultrasound and endobronchial ultrasound for lung cancer staging

    Konge, Lars; Colella, Sara; Vilmann, Peter;

    2015-01-01

    The learning of transesophageal ultrasound guided fine needle aspiration (FNA) (endoscopic ultrasound-FNA), and endobronchial ultrasound guided transbronchial needle aspiration (endosonography) should be based on the following steps: Acquiring theoretical knowledge, training on simulators, and...... supervised performance on patients. Each step should be completed by passing a validated exam before proceeding to the next step. This approach will assure basic competency on all levels, and testing also facilitates learning and improves retention. Competence in endosonography can be based on a systematic...

  8. Conventional ultrasound and contrast-enhanced ultrasound in evaluating the severity of Crohn’s disease

    Liu, Chang; Xu, Xiao-rong; Xu, Hui-Xiong; Liu, Zhan-Ju; Zhang, Yi-feng; Sun, Li-ping; Xu, Jun-Mei; Liu, Lin-Na; Guo, Le-Hang; Bo, Xiao-Wan

    2015-01-01

    Objective: To evaluate the value of conventional ultrasound and contrast-enhanced ultrasound (CEUS) in determining the severity of active Crohn’s disease. Methods: Thirty-seven patients who were considered to be in active period of Crohn’s disease were included. Conventional ultrasound was employed to measure the thicknesses of interior, exterior and the whole bowel walls. Qualitative and quantitative CEUS analysis of the interior, exterior and the whole intestinal walls were also performed. ...

  9. Ultrasound-Assisted Extraction of Total Phenolic Compounds from Inula helenium

    Jin Wang

    2013-01-01

    Full Text Available Ultrasound-assisted extraction (UAE of phenolic compounds from Inula helenium was studied. Effects of ethanol concentration, ultrasonic time, solid-liquid ratio, and number of extractions were investigated. An orthogonal array was constructed to optimize UAE process. The optimized extraction conditions were as follows: ethanol concentration, 30%; solid-liquid ratio, 1 : 20; number of extractions, 2 times; extraction time, 30 min. Under the optimal conditions, the yield of total phenolic compounds and chlorogenic acid was 6.13±0.58 and 1.32±0.17 mg/g, respectively. The results showed that high amounts of phenolic compounds can be extracted from I. helenium by ultrasound-assisted extraction technology.

  10. An optimized ultrasound digital beamformer with dynamic focusing implemented on FPGA.

    Almekkawy, Mohamed; Xu, Jingwei; Chirala, Mohan

    2014-01-01

    We present a resource-optimized dynamic digital beamformer for an ultrasound system based on a field-programmable gate array (FPGA). A comprehensive 64-channel receive beamformer with full dynamic focusing is embedded in the Altera Arria V FPGA chip. To improve spatial and contrast resolution, full dynamic beamforming is implemented by a novel method with resource optimization. This was conceived using the implementation of the delay summation through a bulk (coarse) delay and fractional (fine) delay. The sampling frequency is 40 MHz and the beamformer includes a 240 MHz polyphase filter that enhances the temporal resolution of the system while relaxing the Analog-to-Digital converter (ADC) bandwidth requirement. The results indicate that our 64-channel dynamic beamformer architecture is amenable for a low power FPGA-based implementation in a portable ultrasound system. PMID:25570695

  11. Medical ultrasound imaging method combining minimum variance beamforming and general coherence factor

    WU Wentao; PU Jie; LU Yi

    2012-01-01

    In medical ultrasound imaging field, in order to obtain high resolution and correct the phase errors induced by the velocity in-homogeneity of the tissue, a high-resolution medical ultrasound imaging method combining minimum variance beamforming and general coherence factor was presented. First, the data from the elements is delayed for focusing; then the multi-channel data is used for minimum variance beamforming; at the same time, the data is transformed from array space to beam space to calculate the general coherence factor; in the end, the general coherence factor is used to weight the results of minimum variance beamforming. The medical images are gotten by the imaging system. Experiments based on point object and anechoic cyst object are used to verify the proposed method. The results show the proposed method in the aspects of resolution, contrast and robustness is better than minimum variance beamforming and conventional beamforming.

  12. Measuring submicrometer displacement vectors using high-frame-rate ultrasound imaging.

    Kruizinga, Pieter; Mastik, Frits; Bosch, Johan G; de Jong, Nico; van der Steen, Anton F W; van Soest, Gijs

    2015-10-01

    Measuring the magnitude and direction of tissue displacement provides the basis for the assessment of tissue motion or tissue stiffness. Using conventional displacement tracking by ultrasound delay estimation, only one direction of tissue displacement can be estimated reliably. In this paper, we describe a new technique for estimating the complete two-dimensional displacement vector using high-frame-rate ultrasound imaging. We compute the displacement vector using phase delays that can be measured between pairs of elements within an array. By combining multiple element-pair solutions, we find a new robust estimate for the displacement vector. In this paper, we provide experimental proof that this method permits measurement of the displacement vector for isolated scatterers and diffuse scatterers with high (submicrometer) precision, without the need for beam steering. We also show that we can measure the axial and lateral distension of a carotid artery in a transverse view. PMID:26470036

  13. FTIR spectral imaging as a probe of ultrasound effect on cells in vitro

    Di Giambattista, L; Udroiu, I; Pozzi, D; Cinque, G; Frogley, M D; Giansanti, A; Castellano, A Congiu

    2010-01-01

    Safe and efficient intracellular delivery of genes or drugs is critically important in targeted cancer treatment and gene therapy applications. Ultrasound (US) has been demonstrated to alter the cell membrane permeability due to a biophysical mechanism (Sonoporation) and exploited as a promising non-invasive gene transfer method. The sonoporation process could induce the formation of transient pores without significantly affecting cell viability. This research is aimed at investigating some bioeffects due to Therapeutic Ultrasound (pulsed-1 MHz) which could allow to enhance drugs or genes delivery in a non tumoral cell line. We have used the NIH-3T3 cell line as model system and exposed it to US at two different distances from the source; the effects of this pulsed ultrasonic wave on cells were assessed by Fourier transform infrared (FT-IR) spectroscopic imaging analysis. This technique combined with a focal plane array (FPA) detector has been widely used to study the general biochemical changes in vitro; mor...

  14. High Resolution Depth-Resolved Imaging From Multi-Focal Images for Medical Ultrasound

    Diamantis, Konstantinos; Dalgarno, Paul A.; Greenaway, Alan H.;

    2015-01-01

    in-focus images. The technique is derived from biological microscopy and is validated here with simulated ultrasound data. A linear array probe is used to scan a point scatterer phantom that moves in depth with a controlled step. From the beamformed responses of each scatterer position the image......An ultrasound imaging technique providing subdiffraction limit axial resolution for point sources is proposed. It is based on simultaneously acquired multi-focal images of the same object, and on the image metric of sharpness. The sharpness is extracted by image data and presents higher values for...... sharpness is assessed. Values from all positions plotted together form a curve that peaks at the receive focus, which is set during the beamforming. Selection of three different receive foci for each acquired dataset will result in the generation of three overlapping sharpness curves. A set of three...

  15. Preliminary In-vivo Results For Spatially Coded Synthetic Transmit Aperture Ultrasound Based On Frequency Division

    Gran, Fredrik; Hansen, Kristoffer Lindskov; Jensen, Jørgen Arendt; Nielsen, Michael Bachmann

    This paper investigates the possibility of using spatial coding based on frequency division for in-vivo synthetic transmit aperture (STA) ultrasound imaging. When using spatial encoding for STA, it is possible to use several transmitters simultaneously and separate the signals at the receiver. This...... spectral support, spanning the passband of the ultrasound transducer. The signals can therefore he separated at the receiver using matched filtering. The method is tested using a commercial linear array transducer with a center frequency of 9 MHz and 68% fractional bandwidth. In this paper, the transmit...... be active simultaneously. The method is compared to traditional STA with linear frequency modulation as means of temporal coding. The reference waveform was a 20 ps chirp at 9.37 MHz with a bandwidth of 11.3 MHz. Penetration and resolution is evaluated using a tissue mimicking phantom. The increase...

  16. [Renal ultrasound in fat necrosis].

    Tizki, S; Lasry, F; Elftoiki, F Z; Hadj Khalifa, H; Itri, M; Khadir, K; Benchikhi, H

    2013-07-01

    Subcutaneous fat necrosis is an uncommon disease that may be complicated with potentially fatal hypercalcemia or with nephrocalcinosis. We report on the case of a patient with a history of significant perinatal asphyxia, hospitalized for a urinary tract infection. Lesions of subcutaneous fat necrosis were noted, with asymptomatic hypercalcemia at 3.9mmol/L. A renal ultrasound was performed and showed echogenic medullary pyramids bilaterally, consistent with nephrocalcinosis and left nephrolithiasis. The treatment of hypercalcemia included hyperhydration, a diuretic and corticosteroids. Progression was characterized by the total regression of skin lesions and normalization of serum calcium. Hypercalcemia is a rare complication of subcutaneous fat necrosis. It develops within days to weeks after the appearance of skin lesions. Nephrocalcinosis appears after several weeks or months. Hypercalcemia must be treated in due time to avoid the impact on the kidney. PMID:23726682

  17. Despeckling of medical ultrasound images.

    Michailovich, Oleg V; Tannenbaum, Allen

    2006-01-01

    Speckle noise is an inherent property of medical ultrasound imaging, and it generally tends to reduce the image resolution and contrast, thereby reducing the diagnostic value of this imaging modality. As a result, speckle noise reduction is an important prerequisite, whenever ultrasound imaging is used for tissue characterization. Among the many methods that have been proposed to perform this task, there exists a class of approaches that use a multiplicative model of speckled image formation and take advantage of the logarithmical transformation in order to convert multiplicative speckle noise into additive noise. The common assumption made in a dominant number of such studies is that the samples of the additive noise are mutually uncorrelated and obey a Gaussian distribution. The present study shows conceptually and experimentally that this assumption is oversimplified and unnatural. Moreover, it may lead to inadequate performance of the speckle reduction methods. The study introduces a simple preprocessing procedure, which modifies the acquired radio-frequency images (without affecting the anatomical information they contain), so that the noise in the log-transformation domain becomes very close in its behavior to a white Gaussian noise. As a result, the preprocessing allows filtering methods based on assuming the noise to be white and Gaussian, to perform in nearly optimal conditions. The study evaluates performances of three different, nonlinear filters--wavelet denoising, total variation filtering, and anisotropic diffusion--and demonstrates that, in all these cases, the proposed preprocessing significantly improves the quality of resultant images. Our numerical tests include a series of computer-simulated and in vivo experiments. PMID:16471433

  18. Three-dimensional Mid-air Acoustic Manipulation by Ultrasonic Phased Arrays

    Ochiai, Yoichi; Rekimoto, Jun

    2013-01-01

    The essence of levitation technology is the countervailing of gravity. It is known that an ultrasound standing wave is capable of suspending small particles at its sound pressure nodes. The acoustic axis of the ultrasound beam in conventional studies was parallel to the gravitational force, and the levitated objects were manipulated along the fixed axis (i.e. one-dimensionally) by controlling the phases or frequencies of bolted Langevin-type transducers. In the present study, we considered extended acoustic manipulation whereby millimetre-sized particles were levitated and moved three-dimensionally by localised ultrasonic standing waves, which were generated by ultrasonic phased arrays. Our manipulation system has two original features. One is the direction of the ultrasound beam, which is arbitrary because the force acting toward its centre is also utilised. The other is the manipulation principle by which a localised standing wave is generated at an arbitrary position and moved three-dimensionally by oppose...

  19. Applications of ultrasound in electrochemistry

    Silva Martinez, Susana

    1997-10-01

    The effect of the ultrasound on electrochemical processes has been investigated employing a microelectrode within the cavitating media. Transient mass transport was strongly enhanced in the presence of ultrasound. High rates of mass transfer of up to 1.5 cm s-1 were observed. These high rates of mass transfer were attributed to two cavitation processes. First, bubble collapse at or near the solid-liquid interface with the consequent formation of a high speed liquid microjet directed at the electrode surface. Second, bubble motion near or within the diffusion layer or the electrode. Single current transients were also recorded at high time resolution. These single current transients were attributed to the short-time perturbation of the diffusion field of the microelectrode due to impacts of cavitation bubble collapse followed by a long time relaxation of the diffusion field back to the steady state. The influence of the ultrasonic source to electrode separation, temperature of the bulk solution, electrode potential and electrode size on the magnitude of current transients was also studied. All of these parameters affected markedly the magnitude of the current transients recorded at microelectrode in the presence of ultrasound. An alternative approach is presented to characterise fast heterogeneous electron transfer reactions employing ultrasound as a mass transport enhancement tool. Two innovative techniques, sampled-current voltammetry and sampled-mean current voltammetry, were developed during the course of this thesis. The technique of sample-current voltammetry reported values of the standard rate constant of heterogeneous electron transfer of up to 1.2 cm s-1 in the presence of ultrasound. This technique focuses on the electrochemical phenomena under investigation at the point of impact of the ultrasonic event, produced by asymmetric cavitation bubble collapse near the electrode surface. Bubble dynamics were also examined under the experimental conditions

  20. A numerical study of transcranial focused ultrasound beam propagation at low frequency

    The feasibility of transcranial ultrasound focusing with a non-moving phased array and without skull-specific aberration correction was investigated using computer simulations. Three cadaver skull CT image data sets were incorporated into an acoustic wave transmission model to simulate transskull ultrasound wave propagation. Using a 0.25 MHz hemispherical array (125 mm radius of curvature, 250 mm diameter, 24 255 elements), the simulated beams could be focused and steered with transducer element driving phases and amplitude adjusted for focal beam steering in water (water-path). A total of 82 foci, spanning wide ranges of distance in the three orthogonal dimensions, were simulated to test the focal beam steering capability inside the three skulls. The acoustic pressure distribution in a volume of 20 x 20 x 20 mm3 centred at each focus was calculated with a 0.5 mm spacing in each axis. Clearly defined foci were retained through the skulls (skull-path) in most cases. The skull-path foci were on average 1.6 ± 0.8 mm shifted from their intended locations. The -3 dB skull-path beam width and length were on average 4.3 ± 1.0 mm and 7.7 ± 1.8 mm, respectively. The skull-path sidelobe levels ranged from 25% to 55% of the peak pressure values. The skull-path peak pressure levels were about 10%-40% of their water-path counterparts. Focusing low-frequency beam through skull without skull-specific aberration correction is possible. This method may be useful for applying ultrasound to disrupt the blood-brain barrier for targeted delivery of therapeutic or diagnostic agents, or to induce microbubbles, or for other uses of ultrasound in brain where the required power levels are low and the sharp focusing is not needed

  1. Endoscopic ultrasound features of chronic pancreatitis

    Rana, Surinder Singh; Vilmann, Peter

    2015-01-01

    As endoscopic ultrasound (EUS) is the most sensitive imaging modality for diagnosing pancreatic disorders, it can demonstrate subtle alterations in the pancreatic parenchymal and ductal structure even before traditional imaging and functional testing demonstrate any abnormality. In spite of this...

  2. Preoperative ultrasound mapping of the saphenous vein

    Levi, Niels; Schroeder, T

    1997-01-01

    A prospective series of 92 patients had their greater saphenous vein assessed with duplex ultrasound scanning prior to planned infrainguinal bypass procedures. Sixteen (17%) bypass procedures thrombosed within the first week postoperatively. A naturally occurring optimal vein diameter was...

  3. Ultrasound diagnosis of gastro-oesophageal reflux.

    Naik, D R; Moore, D. J.

    1984-01-01

    A method of diagnosing gastro-oesophageal reflux using ultrasound is described. This method was compared with barium swallow examination in 20 patients and found to be as accurate in infants and young children.

  4. Micromachined Integrated Transducers for Ultrasound Imaging

    la Cour, Mette Funding

    The purpose of this project is to develop capacitive micromachined ultrasonic transducers (CMUTs) for medical imaging. Medical ultrasound transducers used today are fabricated using piezoelectric materials and bulk processing. To fabricate transducers capable of delivering a higher imaging...

  5. Whole breast tissue characterization with ultrasound tomography

    Duric, Neb; Littrup, Peter; Li, Cuiping; Roy, Olivier; Schmidt, Steve; Seamans, John; Wallen, Andrea; Bey-Knight, Lisa

    2015-03-01

    A number of clinical trials have shown that screening ultrasound, supplemental to mammography, detects additional cancers in women with dense breasts. However, labor intensity, operator dependence and high recall rates have limited adoption. This paper describes the use of ultrasound tomography for whole-breast tissue stiffness measurements as a first step toward addressing the issue of high recall rates. The validation of the technique using an anthropomorphic phantom is described. In-vivo applications are demonstrated on 13 breast masses, indicating that lesion stiffness correlates with lesion type as expected. Comparison of lesion stiffness measurements with standard elastography was available for 11 masses and showed a strong correlation between the 2 measures. It is concluded that ultrasound tomography can map out the 3 dimensional distribution of tissue stiffness over the whole breast. Such a capability is well suited for screening where additional characterization may improve the specificity of screening ultrasound, thereby lowering barriers to acceptance.

  6. Endoscopic ultrasound guided radiofrequency ablation in pancreas

    Seicean, Andrada; Tefas, Cristian; Ungureanu, Bogdan;

    2014-01-01

    Radiofrequency ablation of the pancreas represents a more effective tumor-destruction method compared to other ablation techniques. The endoscopic ultrasound guided radiofrequency ablation is indicated for locally advanced, non-metastatic pancreatic adenocarcinoma, without the need of general...

  7. Ultrasound Assisted Extraction of capsaicinoids from peppers

    2008-01-01

    The development of a rapid, reproducible and simple method of extraction of the majority capsaicinoids (nordihydrocapsaicin, capsaicin, dihydrocapsaicin, homocapsaicin and homodihydrocapsaicin) present in hot peppers by the employment of ultrasound-assisted extraction is reported.

  8. Legacy HMSRP Hawaiian Monk Seal Ultrasound Data

    National Oceanic and Atmospheric Administration, Department of Commerce — Ultrasounds measuring the condition of juvenile seals at Laysan Island during 2009-2010, collected when seals were handled as part of the De-Worming Project

  9. Ultrasound-guided percutaneous thoracoabdominal biopsy.

    Ojalehto, M; Tikkakoski, T; Rissanen, T; Apaja-Sarkkinen, M

    2002-03-01

    This review will discuss the benefits and disadvantages of ultrasound-guided percutaneous fine-needle aspiration and cutting needle biopsies. Clinical efficacy, cost-effectiveness, some controversies and safety will be reviewed. PMID:12010294

  10. Nucleic acid delivery with microbubbles and ultrasound.

    Rychak, Joshua J; Klibanov, Alexander L

    2014-06-01

    Nucleic acid-based therapy is a growing field of drug delivery research. Although ultrasound has been suggested to enhance transfection decades ago, it took a combination of ultrasound with nucleic acid carrier systems (microbubbles, liposomes, polyplexes, and viral carriers) to achieve reasonable nucleic acid delivery efficacy. Microbubbles serve as foci for local deposition of ultrasound energy near the target cell, and greatly enhance sonoporation. The major advantage of this approach is in the minimal transfection in the non-insonated non-target tissues. Microbubbles can be simply co-administered with the nucleic acid carrier or can be modified to carry nucleic acid themselves. Liposomes with embedded gas or gas precursor particles can also be used to carry nucleic acid, release and deliver it by the ultrasound trigger. Successful testing in a wide variety of animal models (myocardium, solid tumors, skeletal muscle, and pancreas) proves the potential usefulness of this technique for nucleic acid drug delivery. PMID:24486388

  11. A brief history of ultrasound in rheumatology

    D'Agostino, Maria Antonietta; Terslev, Lene

    2014-01-01

    Musculoskeletal ultrasound is an evolving technique widely used in rheumatology thanks to the numerous advances and the improved work on standardisation. This article deals with the new developments in terms of technology and validation.......Musculoskeletal ultrasound is an evolving technique widely used in rheumatology thanks to the numerous advances and the improved work on standardisation. This article deals with the new developments in terms of technology and validation....

  12. Development of High Frequency Miniature Ultrasound Transducers

    Manh, Tung

    2013-01-01

    Small, high frequency (≥ 10MHz) broadband ultrasound transducers are required in modern medical imaging systems to provide short range, high resolution images for studying of microstructures in soft tissues, such as the composition of small tumors or a vessel wall. The manufacturing of these probes using conventional methods, i.e. lapping and dicing, becomes difficult and expensive for high frequency applications and there is a need to produce small ultrasound transducers with low cost and hi...

  13. Three-Dimensional Ultrasound in Cerebrovascular Evaluation

    Jurašić, Miljenka-Jelena; Zavoreo, Iris; Demarin, Vida

    2006-01-01

    Three-dimensional ultrasound has started developing in the fifth decade of the last century using numerous imaging innovations. For the exploration of extracranial circulation, three-dimensional ultrasound is used primarily on carotid arteries that are easy to access due to their anatomical position. In the evaluation of intracranial circulation, three-dimensionality can be achieved only partially due to the size of the bony window that prevents probe movement in all 360°. Three-dimensional u...

  14. Twofold processing for denoising ultrasound medical images

    P.V.V.Kishore; Kumar, K. V. V.; kumar, D. Anil; M.V.D.Prasad; Goutham, E. N. D.; Rahul, R.; Krishna, C. B. S. Vamsi; Sandeep, Y.

    2015-01-01

    Ultrasound medical (US) imaging non-invasively pictures inside of a human body for disease diagnostics. Speckle noise attacks ultrasound images degrading their visual quality. A twofold processing algorithm is proposed in this work to reduce this multiplicative speckle noise. First fold used block based thresholding, both hard (BHT) and soft (BST), on pixels in wavelet domain with 8, 16, 32 and 64 non-overlapping block sizes. This first fold process is a better denoising method for reducing s...

  15. Atmospheric freeze drying assisted by power ultrasound

    Santacatalina Bonet, Juan Vicente; Carcel Carrión, Juan Andrés; García Pérez, José Vicente; Mulet Pons, Antonio; Simal, S.

    2012-01-01

    [EN] Atmospheric freeze drying (AFD) is considered an alternative to vacuum freeze drying to keep the quality of fresh product. AFD allows continuous drying reducing fix and operating costs, but presents, as main disadvantage, a long drying time required. The application of power ultrasound (US) can accelerate AFD process. The main objective of the present study was to evaluate the application of power ultrasound to improve atmospheric freeze drying of carrot. For that pur...

  16. Applications of ultrasound in food technology

    Zbigniew J. Dolatowski; Joanna Stadnik; Dariusz Stasiak

    2007-01-01

    Ultrasonic is a rapidly growing field of research, which is finding increasing use in the food industry for both the analysis and modification of food products. The sound ranges employed can be divided into high frequency, low energy diagnostic ultrasound and low frequency, high energy power ultrasound. The former is usually used as a non-destructive analytical technique for quality assurance and process control with particular reference to physicochemical properties such as composition, stru...

  17. Detection Performance Theory for Ultrasound Imaging Systems

    Zemp, Roger J.; Parry, Mark D.; Abbey, Craig K.; Insana, Michael F.

    2005-01-01

    A rigorous statistical theory for characterizing the performance of medical ultrasound systems for lesion detection tasks is developed. A design strategy for optimizing ultrasound systems should be to adjust parameters for maximum information content, which is obtained by maximizing the ideal observer performance. Then, given the radio-frequency data, image and signal processing algorithms are designed to extract as much diagnostically relevant information as possible. In this paper, closed-f...

  18. Cerebral ultrasound images in prenatal cytomegalovirus infection.

    Tomà, P; Magnano, G M; Mezzano, P; Lazzini, F; Bonacci, W; Serra, G

    1989-01-01

    A male newborn with prenatal cytomegalovirus infection was referred for cranial ultrasound. The cranial ultrasound demonstrated areas of increased echogenicity in the thalamic and gray nuclei resembling "a branched candlestick". Doppler technique located the "branched candlestick" along the thalamostriate arteries. This image is particularly interesting because to our knowledge it has never before been described in congenital cytomegalovirus infection, but only in congenital rubella. PMID:2550848

  19. Reconstructions in ultrasound modulated optical tomography

    Allmaras, Moritz

    2011-01-01

    We introduce a mathematical model for ultrasound modulated optical tomography and present a simple reconstruction scheme for recovering the spatially varying optical absorption coefficient from scanning measurements with narrowly focused ultrasound signals. Computational results for this model show that the reconstruction of sharp features of the absorption coefficient is possible. A formal linearization of the model leads to an equation with a Fredholm operator, which explains the stability observed in our numerical experiments. © de Gruyter 2011.

  20. 3D Flow reconstruction using ultrasound PIV

    Poelma, C.; Mari, J. M.; Foin, N.; Tang, M.-X.; Krams, R; Caro, C.G.; Weinberg, P.D.; Westerweel, J.

    2009-01-01

    Ultrasound particle image velocimetry (PIV) can be used to obtain velocity fields in non-transparent geometries and/or fluids. In the current study, we use this technique to document the flow in a curved tube, using ultrasound contrast bubbles as flow tracer particles. The performance of the technique is first tested in a straight tube, with both steady laminar and pulsatile flows. Both experiments confirm that the technique is capable of reliable measurements. A number of adaptations are int...

  1. Ultrasound assisted biogas production from landfill leachate

    Highlights: • Effect of low frequency ultrasound pretreatment on leachate was investigated. • Three different ultrasound energy inputs (200, 400 and 600 W/l) was applied. • Low-frequency ultrasound treatment increased soluble COD in landfill leachate. • Application of ultrasound to leachate increased biogas production about 40%. • Application of ultrasound to leachate increased total methane production rate about 20%. - Abstract: The aim of this study is to increase biogas production and methane yield from landfill leachate in anaerobic batch reactors by using low frequency ultrasound as a pretreatment step. In the first part of the study, optimum conditions for solubilization of organic matter in leachate samples were investigated using various sonication durations at an ultrasound frequency of 20 kHz. The level of organic matter solubilization during ultrasonic pretreatment experiments was determined by calculating the ratio of soluble chemical oxygen demand (sCOD) to total chemical oxygen demand (tCOD). The sCOD/tCOD ratio was increased from 47% in raw leachate to 63% after 45 min sonication at 600 W/l. Non-parametric Friedman’s test indicated that ultrasonic pretreatment has a significant effect on sCOD parameter for leachate (p < 0.05). In the second part of the study, anaerobic batch reactors were operated for both ultrasonically pretreated and untreated landfill leachate samples in order to assess the effect of sonication on biogas and methane production rate. In anaerobic batch reactor feed with ultrasonically pretreated leachate, 40% more biogas was obtained compared to the control reactor. For statistical analysis, Mann–Whitney U test was performed to compare biogas and methane production rates for raw and pretreated leachate samples and it has been found that ultrasonic pretreatment significantly enhanced biogas and methane production rates from leachate (p < 0.05) in anaerobic batch reactors. The overall results showed that low frequency

  2. Ultrasound assisted biogas production from landfill leachate

    Oz, Nilgün Ayman, E-mail: nilgunayman@comu.edu.tr; Yarimtepe, Canan Can

    2014-07-15

    Highlights: • Effect of low frequency ultrasound pretreatment on leachate was investigated. • Three different ultrasound energy inputs (200, 400 and 600 W/l) was applied. • Low-frequency ultrasound treatment increased soluble COD in landfill leachate. • Application of ultrasound to leachate increased biogas production about 40%. • Application of ultrasound to leachate increased total methane production rate about 20%. - Abstract: The aim of this study is to increase biogas production and methane yield from landfill leachate in anaerobic batch reactors by using low frequency ultrasound as a pretreatment step. In the first part of the study, optimum conditions for solubilization of organic matter in leachate samples were investigated using various sonication durations at an ultrasound frequency of 20 kHz. The level of organic matter solubilization during ultrasonic pretreatment experiments was determined by calculating the ratio of soluble chemical oxygen demand (sCOD) to total chemical oxygen demand (tCOD). The sCOD/tCOD ratio was increased from 47% in raw leachate to 63% after 45 min sonication at 600 W/l. Non-parametric Friedman’s test indicated that ultrasonic pretreatment has a significant effect on sCOD parameter for leachate (p < 0.05). In the second part of the study, anaerobic batch reactors were operated for both ultrasonically pretreated and untreated landfill leachate samples in order to assess the effect of sonication on biogas and methane production rate. In anaerobic batch reactor feed with ultrasonically pretreated leachate, 40% more biogas was obtained compared to the control reactor. For statistical analysis, Mann–Whitney U test was performed to compare biogas and methane production rates for raw and pretreated leachate samples and it has been found that ultrasonic pretreatment significantly enhanced biogas and methane production rates from leachate (p < 0.05) in anaerobic batch reactors. The overall results showed that low frequency

  3. Ultrasound contrast agents : optical and acoustical characterization

    Sijl, Jeroen

    2009-01-01

    This thesis describes the characterization of the dynamics and the acoustic responses of single BR14 (Bracco Research S.A., Geneva, Switzerland) ultra- sound contrast agent microbubbles under the in°uence of ultrasound. In Ch. 2 of this thesis we investigate the small amplitude behavior of isolated microbubbles acoustically. To ensure that the measured acoustic response orig- inates from one bubble only, it requires the isolation of a single microbubble within an ultrasound beam. Furthermore ...

  4. Design Issues for Therapeutic Ultrasound Angioplasty Waveguides

    Noone, Declan, (Thesis); Gavin, Graham; McGuinness, Garrett

    2008-01-01

    Therapeutic ultrasound angioplasty is a new minimally invasive cardiovascular procedure for disrupting atherosclerotic lesions. Mechanical energy is transmitted in the form of ultrasound waves via long, flexible wire waveguides navigated to the lesion site through the vascular system. The underpinning principle of this technology is that plaque may be disrupted through a combination of direct contact ablation, pressure waves, cavitation and acoustic streaming, which all depend on the amplitud...

  5. Ultrasound features of human carotid plaques

    Östling, Gerd

    2013-01-01

    Atherosclerotic plaques in the carotid arteries are common in a middle-aged population. When a carotid plaque ruptures it may result in a cerebrovascular event. However, only a minor part of carotid plaques will eventually rupture. Finding those plaques is essential to decide the most appropriate treatment strategy. With non-invasive ultrasound the carotid plaques can be visualized for assessment of various features. Plaques that appear dark on the ultrasound image, i.e. echolucent plaques...

  6. Application of ultrasound in periodontics: Part II

    Bains, Vivek K.; Mohan, Ranjana; Bains, Rhythm

    2008-01-01

    Ultrasound offers great potential in development of a noninvasive periodontal assessment tool that would offer great yield real time information, regarding clinical features such as pocket depth, attachment level, tissue thickness, histological change, calculus, bone morphology, as well as evaluation of tooth structure for fracture cracks. In therapeutics, ultrasonic instrumentation is proven effective and efficient in treating periodontal disease. When used properly, ultrasound-based instrum...

  7. Practical sonochemistry power ultrasound uses and applications

    Mason, T J

    2002-01-01

    This updated version of Practical Sonochemistry for advanced students and teachers in chemistry and chemical engineering conveys the increasing growth in applications and equipment to power ultrasound. Equipment now on the market offers a wider range of frequencies with more reproducible experimentation and a variety of scale-up systems. The book provides detailed descriptions of newer ultrasonic equipment and its applications, and practical laboratory uses of ultrasound technology for industrial scale performance.Modern exercises familiarise readers with recent sonochemical operations

  8. Epithelioma of Malherbe: new ultrasound patterns

    Amantea Ada; Panetta Chiara; Drusco Alessandra; Elia Fulvia; Solivetti Francesco M; Di Carlo Aldo

    2010-01-01

    Abstract Backround Calcifying epithelioma of Malherbe, or Pilomatricoma, is considered an uncommon cutaneous neoplasia, normally occurring in children as a solitary, firm, asymptomatic, hard, subcutaneous, slowly growing nodule on the face, neck, or proximal upper extremity. In literature, two Pilomatricoma ultrasound patterns are described: the totally calcified nodule and the hypoechoic nodule with internal calcific foci. High frequency ultrasound has not yet been applied for routine diagno...

  9. Application of Ultrasound in Food Drying

    Senem Tüfekçi; Sami Gökhan Özkal

    2015-01-01

    Drying has a privileged position in all food preservation methods by reducing of existing water content in food not allowing spoilage, providing a precise and cheap preservation opportunity. Sound waves with frequencies above human hearing are called as ultrasound. Ultrasound which is applied prior to drying as pretreatment or simultaneously is effective on drying performance of products. It is known that diffusion of water increased and total process time shortened in processes that ultrason...

  10. Reality named endoscopic ultrasound biliary drainage

    Guedes, Hugo Gonçalo; Lopes, Roberto Iglesias; de Oliveira, Joel Fernandez; Artifon, Everson Luiz de Almeida

    2015-01-01

    Endoscopic ultrasound (EUS) is used for diagnosis and evaluation of many diseases of the gastrointestinal (GI) tract. In the past, it was used to guide a cholangiography, but nowadays it emerges as a powerful therapeutic tool in biliary drainage. The aims of this review are: outline the rationale for endoscopic ultrasound-guided biliary drainage (EGBD); detail the procedural technique; evaluate the clinical outcomes and limitations of the method; and provide recommendations for the practicing...

  11. Optimizing Chemical Sensor Array Sizes

    Optimal selection of array sensors for a chemical sensing application is a nontrivial task. It is commonly believed that ''more is better'' when choosing the number of sensors required to achieve good chemical selectivity. However, cost and system complexity issues point towards the choice of small arrays. A quantitative array optimization is carried out to explore the selectivity of arrays of partially-selective chemical sensors as a function of array size. It is shown that modest numbers (dozens) of target analytes are completely distinguished with a range of arrays sizes. However, the array selectivity and the robustness against sensor sensitivity variability are significantly degraded if the array size is increased above a certain number of sensors, so that relatively small arrays provide the best performance. The results also suggest that data analyses for very large arrays of partially-selective sensors will be optimized by separately anal yzing small sensor subsets

  12. Ultrasound detection of nonpalpable mammographically occult malignancy

    To evaluate the prevalence of occult malignancy with screening breast ultrasound. All ultrasound-guided core needle breast biopsies performed between January 1, 1999, and June 30, 2001, were retrospectively reviewed. Lesions were identified during screening breast ultrasound in high-risk women with no mammographic or palpable abnormality in either breast, a unilateral mammographic or palpable abnormality in the contralateral breast, or a unilateral mammographic or palpable abnormality in a different quadrant of the same breast. All ultrasound-detected lesions were histologically verified. Six hundred and fifty-two women with a mean age of 49 years underwent 698 biopsies during the study period. Three hundred and forty-nine of these lesions were detected at screening breast ultrasound. Out of 349, 11 (3.2%) had a mammographically and clinically occult malignancy. Nine cancers were found in women with no mammographic or palpable abnormality. Two cancers were found in the same breast as the mammographic or palpable abnormality. None were found in the breast contralateral to a palpable or mammographic abnormality. Screening breast ultrasound of high-risk women has a similar detection rate for occult carcinoma as screening mammography, but has a low positive predictive value in cases where biopsy is performed. (author)

  13. Intravascular ultrasound imaging following balloon angioplasty.

    Tobis, J M; Mahon, D J; Moriuchi, M; Honye, J; McRae, M

    1991-01-01

    Despite its long history and reliability, contrast angiography has several inherent limitations. Because it is a two-dimensional projection image of the lumen contour, the wall thickness cannot be measured and the plaque itself is not visualized. This results in an underestimation of the amount of atherosclerotic disease by angiography. An assessment of atherosclerosis could be improved by an imaging modality: (1) that has an inherent larger magnification than angiography and (2) that directly visualizes the plaque. Intravascular ultrasound fulfils these criteria. This presentation will provide evidence that intravascular ultrasound may prove complimentary or even superior to angiography as an imaging modality. Intravascular ultrasound demonstrates excellent representations of lumen and plaque morphology of in vitro specimens compared with histology. There is very close intraobserver and interobserver variability of measurements made from intravascular ultrasound images. Phantom studies of stenoses in a tube model demonstrate that angiography can misrepresent the severity of stenosis when the lumen contour is irregular and not a typical ellipse, whereas intravascular ultrasound reproduces the cross-sectional morphology more accurately since it images the artery from within. In vitro studies of the atherosclerotic plaque tissue characteristics compare closely with the echo representation of fibrosis, calcification, and lipid material. In addition, in vitro studies of balloon angioplasty demonstrate that intravascular ultrasound accurately represents the changes in the structure of artery segments following balloon dilatation. PMID:1833473

  14. Ultrasound and MR imaging of diabetic mastopathy

    AIM: To review the imaging findings of diabetic mastopathy, and document the colour flow ultrasound and MR imaging features in this benign condition. MATERIALS AND METHODS: Diabetic mastopathy was clinically and histologically diagnosed in eight lesions in six women. All six women underwent conventional mammography and high frequency grey-scale ultrasound. Colour flow ultrasound was performed additionally in six lesions in four women and MR imaging in four lesions in three women before biopsy. The imaging findings were reviewed and correlated with final histological diagnosis. RESULTS: Mammography showed regional asymmetric increased opacity with ill-defined margins in all lesions. A heterogeneously hypoechoic mass with ill-defined margins was identified on high frequency grey-scale ultrasound in all lesions. Marked posterior acoustic shadowing was present in seven of eight (88%) lesions. Six lesions interrogated with colour flow ultrasound showed absence of Doppler signal. MR imaging in three women revealed non-specific stromal enhancement. CONCLUSION: Diabetic mastopathy shows absence of Doppler signal on colour flow ultrasound and non-specific stromal enhancement on MR imaging. Wong K.T. et al. (2002)

  15. Epithelioma of Malherbe: new ultrasound patterns

    Amantea Ada

    2010-05-01

    Full Text Available Abstract Backround Calcifying epithelioma of Malherbe, or Pilomatricoma, is considered an uncommon cutaneous neoplasia, normally occurring in children as a solitary, firm, asymptomatic, hard, subcutaneous, slowly growing nodule on the face, neck, or proximal upper extremity. In literature, two Pilomatricoma ultrasound patterns are described: the totally calcified nodule and the hypoechoic nodule with internal calcific foci. High frequency ultrasound has not yet been applied for routine diagnosis of Pilomatricoma. The aim of the study was to retrospectively identify specific ultrasound features. Methods We retrieved 124 histologically Pilomatricoma cases: 28 patients with 32 lesions were preoperatively evaluated with ultrasound. Results 22/32 have shown a solid formation, hypoechoic, with a sharp outline. Of these 22, 10 lesions were completely calcifying and 12 partially calcified. In 3/32 lesions with uncertain diagnosis, ultrasounds showed a complex/mixed pattern with pseudo-fluid areas and microspots. 7/32 lesions with US different diagnosis included 3 complex lesions, 2 cystic lesions and 2 solid nodular lesions. Conclusion In addition to well-known ultrasound patterns (completely calcified and partially calcified we identified three new, not yet described, patterns that constitute the 31% of the cases: complex, pseudocistyc and pseudotumoral.

  16. INTRAOPERATIVE ULTRASOUND FOR HEPATIC NEOPLASM DURING SURGERY

    1999-01-01

    Objective.Th purpose of this study was to determine the impact of intraoperative ultrasound(IOUS)on the management of patients with neoplasms of the liver.Methods.Forty-nine patients operated on for liver or other pathologic processes were examined intraopertively with 5.0 MHz special ultrasound transducers during surgical exploration of the abdomen.Subjects were evaluated because of known or suspected disease of the liver.Preoperative imaging studies included percutaneous ultrasound(n=49),magnetic resonance imaging(n=11),and computed tomography(n=34).Intraoperative evaluation on all patients included inspection,bimanual palpation,and ultrasnography.Comparison between preoperative imagings and IOUS were analysed.Results.Sensitivity for detection of hepatic neoplasms showed in intraoperative ultrasound,percutaneous ultrasound,magnetic resonance imaging andcomputed tomography as 100%(23/23),74%(17/23),74%(14/19) and 75%(6/8).Specificity showed 100%(26/26),100%(26/26),93%(14/15) and 67(2/3).In seven patients(14%),the neoplasms were not found by inspection,bimanual palpation,and identified only by IOUS.Conclusions.Intraoperative ultrasound is the most sensitive and specific method for detection and surgery of liver neoplasms,especially the occult neoplasms and small size lesion(<2cm).

  17. INTRAOPERATIVE ULTRASOUND FOR HEPATIC NEOPLASM DURING SURGERY

    于健春; 钟守先

    1999-01-01

    Objective. The purpose of this study was to determine the impact of intraoperative ultrasound(IOUS) on the management of patients with neoplasms of the liver. ethods. Forty-nlne patients operated on for liver or other pathologic processes were examined intraoperatively with .5.0 MHz special ultrasound transducers during surgical exploration of the abdomen. Subjects were evaluated because of known or suspected disease of the liver. Preoperative imaging studies izmluded percutaneotts ultrasound (n=49),magnetic resonance imaging(n= ll),and computed tomography(n=34). Intraoparative evaluation on all patients included inspection, bimanual palpation,and ultrasonography.Comparison between preoperative imagings and IOUS were analysed. Results. Sensitivity for detection of hepatic neoplasms showed in intraoperative ultrasound, percutaneotts ultrasound,magnetic resonance imaging and computed tomography as 100%(23/23),74%(17/23),74%(14/19) and 75 % (6/8). Specificity showed 100% (26/26), 100% (26/26), 93 % (14/15) and 67 (2/3). In seveaa patlents(14%) ,the neoplasms were not found by inspection ,bimanual palpation,and identified only by IOUS. Conclusums. Intraoparative ultrasound is the most sensitive and specific method for detection and surgery of liver neoplasms,especially the occult neoplasms and small size lesion(<2cm).

  18. FPGA-based reconfigurable processor for ultrafast interlaced ultrasound and photoacoustic imaging.

    Alqasemi, Umar; Li, Hai; Aguirre, Andrés; Zhu, Quing

    2012-07-01

    In this paper, we report, to the best of our knowledge, a unique field-programmable gate array (FPGA)-based reconfigurable processor for real-time interlaced co-registered ultrasound and photoacoustic imaging and its application in imaging tumor dynamic response. The FPGA is used to control, acquire, store, delay-and-sum, and transfer the data for real-time co-registered imaging. The FPGA controls the ultrasound transmission and ultrasound and photoacoustic data acquisition process of a customized 16-channel module that contains all of the necessary analog and digital circuits. The 16-channel module is one of multiple modules plugged into a motherboard; their beamformed outputs are made available for a digital signal processor (DSP) to access using an external memory interface (EMIF). The FPGA performs a key role through ultrafast reconfiguration and adaptation of its structure to allow real-time switching between the two imaging modes, including transmission control, laser synchronization, internal memory structure, beamforming, and EMIF structure and memory size. It performs another role by parallel accessing of internal memories and multi-thread processing to reduce the transfer of data and the processing load on the DSP. Furthermore, because the laser will be pulsing even during ultrasound pulse-echo acquisition, the FPGA ensures that the laser pulses are far enough from the pulse-echo acquisitions by appropriate time-division multiplexing (TDM). A co-registered ultrasound and photoacoustic imaging system consisting of four FPGA modules (64-channels) is constructed, and its performance is demonstrated using phantom targets and in vivo mouse tumor models. PMID:22828830

  19. Correlations among carcass traits taken by ultrasound and after slaughter in Mediterranean (Bubalus bubalis young bulls

    R.S. Bonilha Pinheiro

    2010-02-01

    Full Text Available The objective of this work was to estimate the correlations among measurements taken in vivo with ultrasound equipment with some carcass traits measured after slaughter. Twenty eight Mediterranean bulls, with average shrunk body weight of 330 kg and 14 months of age, were fed by 120 days with high concentrate diets. The shrunk body weight, the ribeye area (REAU, the back fat thickness (FTU over the Longissimus dorsi muscle between 12ª and 13ª ribs and rump fat (EGP8U, were measured at 28 days intervals. Real-time ultrasound equipment Piemedical Scanner 200 VET, with 18 cm linear array transducer was utilized. After the slaughter, the hot carcass weight (PCQ and the kidney, pelvic and inguinal fat (GRPI were weighted and the dressing percentage (DP calculated. After 24 hours of cooling the ribeye area (REAC, backfat thickness (FTC and rump fat (EGP8C were measured. Both the REAC, FTC and EGP8C were underestimated by ultrasound measurements. The Pearson correlation coefficients for ribeye area, backfat thickness and rump fat measured in the carcass and with ultrasound, were 0.96, 0.99 and 0.91, respectively. The coefficient between DP and REAU was 0.47; 0.45 between DP and REAC, 0.56 between DP and FTU and 0.58 between DP and FTC. DP presented a 0.59 correlation coefficient with EGP8U. The Spearman correlation was estimated between REAU and REAC, FTU and FTC, EGP8U and EGP8C, and the values were 0.96, 0.99 and 0.91 , respectively. The ultrasound measures could be used to estimate carcass traits in buffaloes with good accuracy.

  20. Imaging antenna arrays

    Rutledge, D. B.; Muha, M. S.

    1982-01-01

    Many millimeter and far-infrared imaging systems are limited in sensitivity and speed because they depend on a single scanned element. Because of recent advances in planar detectors such as Schottky diodes, superconducting tunnel junctions, and microbolometers, an attractive approach to this problem is a planar antenna array with integrated detectors. A planar line antenna array and optical system for imaging has been developed. The significant advances are a 'reverse-microscope' optical configuration and a modified bow-tie antenna design. In the 'reverse-microscope' configuration, a lens is attached to the bottom of the substrate containing the antennas. Imaging is done through the substrate. This configuration eliminates the troublesome effects of substrate surface waves. The substrate lens has only a single refracting surface, making possible a virtually aplanatic system, with little spherical aberration or coma. The array is characterized by an optical transfer function that is easily measured. An array with 19 dB crosstalk levels between adjacent antennas has been tested and it was found that the array captured 50 percent of the available power. This imaging system was diffraction limited.