Time reversal and phase coherent music techniques for super-resolution ultrasound imaging

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

Huang, Lianjie; Labyed, Yassin

Systems and methods for super-resolution ultrasound imaging using a windowed and generalized TR-MUSIC algorithm that divides the imaging region into overlapping sub-regions and applies the TR-MUSIC algorithm to the windowed backscattered ultrasound signals corresponding to each sub-region. The algorithm is also structured to account for the ultrasound attenuation in the medium and the finite-size effects of ultrasound transducer elements. A modified TR-MUSIC imaging algorithm is used to account for ultrasound scattering from both density and compressibility contrasts. The phase response of ultrasound transducer elements is accounted for in a PC-MUSIC system.

Synthetic aperture imaging in ultrasound calibration

NASA Astrophysics Data System (ADS)

Ameri, Golafsoun; Baxter, John S. H.; McLeod, A. Jonathan; Jayaranthe, Uditha L.; Chen, Elvis C. S.; Peters, Terry M.

2014-03-01

Ultrasound calibration allows for ultrasound images to be incorporated into a variety of interventional applica­ tions. Traditional Z- bar calibration procedures rely on wired phantoms with an a priori known geometry. The line fiducials produce small, localized echoes which are then segmented from an array of ultrasound images from different tracked probe positions. In conventional B-mode ultrasound, the wires at greater depths appear blurred and are difficult to segment accurately, limiting the accuracy of ultrasound calibration. This paper presents a novel ultrasound calibration procedure that takes advantage of synthetic aperture imaging to reconstruct high resolution ultrasound images at arbitrary depths. In these images, line fiducials are much more readily and accu­ rately segmented, leading to decreased calibration error. The proposed calibration technique is compared to one based on B-mode ultrasound. The fiducial localization error was improved from 0.21mm in conventional B-mode images to 0.15mm in synthetic aperture images corresponding to an improvement of 29%. This resulted in an overall reduction of calibration error from a target registration error of 2.00mm to 1.78mm, an improvement of 11%. Synthetic aperture images display greatly improved segmentation capabilities due to their improved resolution and interpretability resulting in improved calibration.

High-Accuracy Ultrasound Contrast Agent Detection Method for Diagnostic Ultrasound Imaging Systems.

PubMed

Ito, Koichi; Noro, Kazumasa; Yanagisawa, Yukari; Sakamoto, Maya; Mori, Shiro; Shiga, Kiyoto; Kodama, Tetsuya; Aoki, Takafumi

2015-12-01

An accurate method for detecting contrast agents using diagnostic ultrasound imaging systems is proposed. Contrast agents, such as microbubbles, passing through a blood vessel during ultrasound imaging are detected as blinking signals in the temporal axis, because their intensity value is constantly in motion. Ultrasound contrast agents are detected by evaluating the intensity variation of a pixel in the temporal axis. Conventional methods are based on simple subtraction of ultrasound images to detect ultrasound contrast agents. Even if the subject moves only slightly, a conventional detection method will introduce significant error. In contrast, the proposed technique employs spatiotemporal analysis of the pixel intensity variation over several frames. Experiments visualizing blood vessels in the mouse tail illustrated that the proposed method performs efficiently compared with conventional approaches. We also report that the new technique is useful for observing temporal changes in microvessel density in subiliac lymph nodes containing tumors. The results are compared with those of contrast-enhanced computed tomography. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Application of analyzer based X-ray imaging technique for detection of ultrasound induced cavitation bubbles from a physical therapy unit.

PubMed

Izadifar, Zahra; Belev, George; Babyn, Paul; Chapman, Dean

2015-10-19

The observation of ultrasound generated cavitation bubbles deep in tissue is very difficult. The development of an imaging method capable of investigating cavitation bubbles in tissue would improve the efficiency and application of ultrasound in the clinic. Among the previous imaging modalities capable of detecting cavitation bubbles in vivo, the acoustic detection technique has the positive aspect of in vivo application. However the size of the initial cavitation bubble and the amplitude of the ultrasound that produced the cavitation bubbles, affect the timing and amplitude of the cavitation bubbles' emissions. The spatial distribution of cavitation bubbles, driven by 0.8835 MHz therapeutic ultrasound system at output power of 14 Watt, was studied in water using a synchrotron X-ray imaging technique, Analyzer Based Imaging (ABI). The cavitation bubble distribution was investigated by repeated application of the ultrasound and imaging the water tank. The spatial frequency of the cavitation bubble pattern was evaluated by Fourier analysis. Acoustic cavitation was imaged at four different locations through the acoustic beam in water at a fixed power level. The pattern of cavitation bubbles in water was detected by synchrotron X-ray ABI. The spatial distribution of cavitation bubbles driven by the therapeutic ultrasound system was observed using ABI X-ray imaging technique. It was observed that the cavitation bubbles appeared in a periodic pattern. The calculated distance between intervals revealed that the distance of frequent cavitation lines (intervals) is one-half of the acoustic wave length consistent with standing waves. This set of experiments demonstrates the utility of synchrotron ABI for visualizing cavitation bubbles formed in water by clinical ultrasound systems working at high frequency and output powers as low as a therapeutic system.

Ultrasound Molecular Imaging: Moving Towards Clinical Translation

PubMed Central

Abou-Elkacem, Lotfi; Bachawal, Sunitha V.; Willmann, Jürgen K.

2015-01-01

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. PMID:25851932

Ultrasound wave propagation in tissue and scattering from microbubbles for echo particle image velocimetry technique.

PubMed

Mukdadi, Osama; Shandas, Robin

2004-01-01

Nonlinear wave propagation in tissue can be employed for tissue harmonic imaging, ultrasound surgery, and more effective tissue ablation for high intensity focused ultrasound (HIFU). Wave propagation in soft tissue and scattering from microbubbles (ultrasound contrast agents) are modeled to improve detectability, signal-to-noise ratio, and contrast harmonic imaging used for echo particle image velocimetry (Echo-PIV) technique. The wave motion in nonlinear material (tissue) is studied using KZK-type parabolic evolution equation. This model considers ultrasound beam diffraction, attenuation, and tissue nonlinearity. Time-domain numerical model is based on that originally developed by Lee and Hamilton [J. Acoust. Soc. Am 97:906-917 (1995)] for axi-symmetric acoustic field. The initial acoustic waveform emitted from the transducer is assumed to be a broadband wave modulated by Gaussian envelope. Scattering from microbubbles seeded in the blood stream is characterized. Hence, we compute the pressure field impinges the wall of a coated microbubble; the dynamics of oscillating microbubble can be modeled using Rayleigh-Plesset-type equation. Here, the continuity and the radial-momentum equation of encapsulated microbubbles are used to account for the lipid layer surrounding the microbubble. Numerical results show the effects of tissue and microbubble nonlinearities on the propagating pressure wave field. These nonlinearities have a strong influence on the waveform distortion and harmonic generation of the propagating and scattering waves. Results also show that microbubbles have stronger nonlinearity than tissue, and thus improves S/N ratio. These theoretical predictions of wave phenomena provide further understanding of biomedical imaging technique and provide better system design.

Motion Detection in Ultrasound Image-Sequences Using Tensor Voting

NASA Astrophysics Data System (ADS)

Inba, Masafumi; Yanagida, Hirotaka; Tamura, Yasutaka

2008-05-01

Motion detection in ultrasound image sequences using tensor voting is described. We have been developing an ultrasound imaging system adopting a combination of coded excitation and synthetic aperture focusing techniques. In our method, frame rate of the system at distance of 150 mm reaches 5000 frame/s. Sparse array and short duration coded ultrasound signals are used for high-speed data acquisition. However, many artifacts appear in the reconstructed image sequences because of the incompleteness of the transmitted code. To reduce the artifacts, we have examined the application of tensor voting to the imaging method which adopts both coded excitation and synthetic aperture techniques. In this study, the basis of applying tensor voting and the motion detection method to ultrasound images is derived. It was confirmed that velocity detection and feature enhancement are possible using tensor voting in the time and space of simulated ultrasound three-dimensional image sequences.

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

NASA Astrophysics Data System (ADS)

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.

Ultrasound image guidance of cardiac interventions

NASA Astrophysics Data System (ADS)

Peters, Terry M.; Pace, Danielle F.; Lang, Pencilla; Guiraudon, Gérard M.; Jones, Douglas L.; Linte, Cristian A.

2011-03-01

Surgical procedures often have the unfortunate side-effect of causing the patient significant trauma while accessing the target site. Indeed, in some cases the trauma inflicted on the patient during access to the target greatly exceeds that caused by performing the therapy. Heart disease has traditionally been treated surgically using open chest techniques with the patient being placed "on pump" - i.e. their circulation being maintained by a cardio-pulmonary bypass or "heart-lung" machine. Recently, techniques have been developed for performing minimally invasive interventions on the heart, obviating the formerly invasive procedures. These new approaches rely on pre-operative images, combined with real-time images acquired during the procedure. Our approach is to register intra-operative images to the patient, and use a navigation system that combines intra-operative ultrasound with virtual models of instrumentation that has been introduced into the chamber through the heart wall. This paper illustrates the problems associated with traditional ultrasound guidance, and reviews the state of the art in real-time 3D cardiac ultrasound technology. In addition, it discusses the implementation of an image-guided intervention platform that integrates real-time ultrasound with a virtual reality environment, bringing together the pre-operative anatomy derived from MRI or CT, representations of tracked instrumentation inside the heart chamber, and the intra-operatively acquired ultrasound images.

Development of ultrasound bioprobe for biological imaging

PubMed Central

Shekhawat, Gajendra S.; Dudek, Steven M.; Dravid, Vinayak P.

2017-01-01

We report the development of an ultrasound bioprobe for in vitro molecular imaging. In this method, the phase of the scattered ultrasound wave is mapped to provide in vitro and intracellular imaging with nanometer-scale resolution under physiological conditions. We demonstrated the technique by successfully imaging a magnetic core in silica core shells and the stiffness image of intracellular fibers in endothelial cells that were stimulated with thrombin. The findings demonstrate a significant advancement in high-resolution ultrasound imaging of biological systems with acoustics under physiological conditions. These will open up various applications in biomedical and molecular imaging with subsurface resolution down to the nanometer scale. PMID:29075667

Medical Imaging with Ultrasound: Some Basic Physics.

ERIC Educational Resources Information Center

Gosling, R.

1989-01-01

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

Three-dimensional ultrasound imaging of the prostate

NASA Astrophysics Data System (ADS)

Fenster, Aaron; Downey, Donal B.

1999-05-01

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

Ultrasound molecular imaging: Moving toward clinical translation.

PubMed

Abou-Elkacem, Lotfi; Bachawal, Sunitha V; Willmann, Jürgen K

2015-09-01

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. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Ultrasound Activated Contrast Imaging for Prostate Cancer Detection

DTIC Science & Technology

2007-03-01

SUBTITLE 5a. CONTRACT NUMBER Ultrasound Activated Contrast Imaging for Prostate Cancer Detection 5b. GRANT NUMBER DAMD17-03-1-0119 5c. PROGRAM...ABSTRACT: The current project proposes todevelop a novel ultrasound contrast imaging technique (called EEI) for better visualization of the

Focused Ultrasound Steering for Harmonic Motion Imaging.

PubMed

Han, Yang; Payen, Thomas; Wang, Shutao; Konofagou, Elisa

2018-02-01

Harmonic motion imaging (HMI) is a radiation-force-based ultrasound elasticity imaging technique, which is designed for both tissue relative stiffness imaging and reliable high-intensity focused ultrasound treatment monitoring. The objective of this letter is to develop and demonstrate the feasibility of 2-D focused ultrasound (FUS) beam steering for HMI using a 93-element, FUS phased array. HMI with steered FUS beam was acquired in tissue-mimicking phantoms. The HMI displacement was imaged within the steering range of ±1.7 mm laterally and ±2 mm axially. Using the steered FUS beam, HMI can be used to image a larger tissue volume with higher efficiency and without requiring mechanical movement of the transducer.

Imaging in anatomy: a comparison of imaging techniques in embalmed human cadavers

PubMed Central

2013-01-01

Background A large variety of imaging techniques is an integral part of modern medicine. Introducing radiological imaging techniques into the dissection course serves as a basis for improved learning of anatomy and multidisciplinary learning in pre-clinical medical education. Methods Four different imaging techniques (ultrasound, radiography, computed tomography, and magnetic resonance imaging) were performed in embalmed human body donors to analyse possibilities and limitations of the respective techniques in this peculiar setting. Results The quality of ultrasound and radiography images was poor, images of computed tomography and magnetic resonance imaging were of good quality. Conclusion Computed tomography and magnetic resonance imaging have a superior image quality in comparison to ultrasound and radiography and offer suitable methods for imaging embalmed human cadavers as a valuable addition to the dissection course. PMID:24156510

Review of quantitative ultrasound: envelope statistics and backscatter coefficient imaging and contributions to diagnostic ultrasound

PubMed Central

Oelze, Michael L.; Mamou, Jonathan

2017-01-01

Conventional medical imaging technologies, including ultrasound, have continued to improve over the years. For example, in oncology, medical imaging is characterized by high sensitivity, i.e., the ability to detect anomalous tissue features, but the ability to classify these tissue features from images often lacks specificity. As a result, a large number of biopsies of tissues with suspicious image findings are performed each year with a vast majority of these biopsies resulting in a negative finding. To improve specificity of cancer imaging, quantitative imaging techniques can play an important role. Conventional ultrasound B-mode imaging is mainly qualitative in nature. However, quantitative ultrasound (QUS) imaging can provide specific numbers related to tissue features that can increase the specificity of image findings leading to improvements in diagnostic ultrasound. QUS imaging techniques can encompass a wide variety of techniques including spectral-based parameterization, elastography, shear wave imaging, flow estimation and envelope statistics. Currently, spectral-based parameterization and envelope statistics are not available on most conventional clinical ultrasound machines. However, in recent years QUS techniques involving spectral-based parameterization and envelope statistics have demonstrated success in many applications, providing additional diagnostic capabilities. Spectral-based techniques include the estimation of the backscatter coefficient, estimation of attenuation, and estimation of scatterer properties such as the correlation length associated with an effective scatterer diameter and the effective acoustic concentration of scatterers. Envelope statistics include the estimation of the number density of scatterers and quantification of coherent to incoherent signals produced from the tissue. Challenges for clinical application include correctly accounting for attenuation effects and transmission losses and implementation of QUS on clinical

Acoustic Radiation Force Elasticity Imaging in Diagnostic Ultrasound

PubMed Central

Doherty, Joshua R.; Trahey, Gregg E.; Nightingale, Kathryn R.; Palmeri, Mark L.

2013-01-01

The development of ultrasound-based elasticity imaging methods has been the focus of intense research activity since the mid-1990s. In characterizing the mechanical properties of soft tissues, these techniques image an entirely new subset of tissue properties that cannot be derived with conventional ultrasound techniques. Clinically, tissue elasticity is known to be associated with pathological condition and with the ability to image these features in vivo, elasticity imaging methods may prove to be invaluable tools for the diagnosis and/or monitoring of disease. This review focuses on ultrasound-based elasticity imaging methods that generate an acoustic radiation force to induce tissue displacements. These methods can be performed non-invasively during routine exams to provide either qualitative or quantitative metrics of tissue elasticity. A brief overview of soft tissue mechanics relevant to elasticity imaging is provided, including a derivation of acoustic radiation force, and an overview of the various acoustic radiation force elasticity imaging methods. PMID:23549529

Acoustic radiation force elasticity imaging in diagnostic ultrasound.

PubMed

Doherty, Joshua R; Trahey, Gregg E; Nightingale, Kathryn R; Palmeri, Mark L

2013-04-01

The development of ultrasound-based elasticity imaging methods has been the focus of intense research activity since the mid-1990s. In characterizing the mechanical properties of soft tissues, these techniques image an entirely new subset of tissue properties that cannot be derived with conventional ultrasound techniques. Clinically, tissue elasticity is known to be associated with pathological condition and with the ability to image these features in vivo; elasticity imaging methods may prove to be invaluable tools for the diagnosis and/or monitoring of disease. This review focuses on ultrasound-based elasticity imaging methods that generate an acoustic radiation force to induce tissue displacements. These methods can be performed noninvasively during routine exams to provide either qualitative or quantitative metrics of tissue elasticity. A brief overview of soft tissue mechanics relevant to elasticity imaging is provided, including a derivation of acoustic radiation force, and an overview of the various acoustic radiation force elasticity imaging methods.

Standards of ultrasound imaging of the adrenal glands

PubMed Central

Jakubowski, Wiesław S.; Dobruch-Sobczak, Katarzyna; Kasperlik-Załuska, Anna A.

2015-01-01

Adrenal glands are paired endocrine glands located over the upper renal poles. Adrenal pathologies have various clinical presentations. They can coexist with the hyperfunction of individual cortical zones or the medulla, insufficiency of the adrenal cortex or retained normal hormonal function. The most common adrenal masses are tumors incidentally detected in imaging examinations (ultrasound, tomography, magnetic resonance imaging), referred to as incidentalomas. They include a range of histopathological entities but cortical adenomas without hormonal hyperfunction are the most common. Each abdominal ultrasound scan of a child or adult should include the assessment of the suprarenal areas. If a previously non-reported, incidental solid focal lesion exceeding 1 cm (incidentaloma) is detected in the suprarenal area, computed tomography or magnetic resonance imaging should be conducted to confirm its presence and for differentiation and the tumor functional status should be determined. Ultrasound imaging is also used to monitor adrenal incidentaloma that is not eligible for a surgery. The paper presents recommendations concerning the performance and assessment of ultrasound examinations of the adrenal glands and their pathological lesions. The article includes new ultrasound techniques, such as tissue harmonic imaging, spatial compound imaging, three-dimensional ultrasound, elastography, contrast-enhanced ultrasound and parametric imaging. The guidelines presented above are consistent with the recommendations of the Polish Ultrasound Society. PMID:26807295

Review of Quantitative Ultrasound: Envelope Statistics and Backscatter Coefficient Imaging and Contributions to Diagnostic Ultrasound.

PubMed

Oelze, Michael L; Mamou, Jonathan

2016-02-01

Conventional medical imaging technologies, including ultrasound, have continued to improve over the years. For example, in oncology, medical imaging is characterized by high sensitivity, i.e., the ability to detect anomalous tissue features, but the ability to classify these tissue features from images often lacks specificity. As a result, a large number of biopsies of tissues with suspicious image findings are performed each year with a vast majority of these biopsies resulting in a negative finding. To improve specificity of cancer imaging, quantitative imaging techniques can play an important role. Conventional ultrasound B-mode imaging is mainly qualitative in nature. However, quantitative ultrasound (QUS) imaging can provide specific numbers related to tissue features that can increase the specificity of image findings leading to improvements in diagnostic ultrasound. QUS imaging can encompass a wide variety of techniques including spectral-based parameterization, elastography, shear wave imaging, flow estimation, and envelope statistics. Currently, spectral-based parameterization and envelope statistics are not available on most conventional clinical ultrasound machines. However, in recent years, QUS techniques involving spectral-based parameterization and envelope statistics have demonstrated success in many applications, providing additional diagnostic capabilities. Spectral-based techniques include the estimation of the backscatter coefficient (BSC), estimation of attenuation, and estimation of scatterer properties such as the correlation length associated with an effective scatterer diameter (ESD) and the effective acoustic concentration (EAC) of scatterers. Envelope statistics include the estimation of the number density of scatterers and quantification of coherent to incoherent signals produced from the tissue. Challenges for clinical application include correctly accounting for attenuation effects and transmission losses and implementation of QUS on

Detecting breast microcalcifications using super-resolution ultrasound imaging: a clinical study

NASA Astrophysics Data System (ADS)

Huang, Lianjie; Labyed, Yassin; Hanson, Kenneth; Sandoval, Daniel; Pohl, Jennifer; Williamson, Michael

2013-03-01

Imaging breast microcalcifications is crucial for early detection and diagnosis of breast cancer. It is challenging for current clinical ultrasound to image breast microcalcifications. However, new imaging techniques using data acquired with a synthetic-aperture ultrasound system have the potential to significantly improve ultrasound imaging. We recently developed a super-resolution ultrasound imaging method termed the phase-coherent multiple-signal classification (PC-MUSIC). This signal subspace method accounts for the phase response of transducer elements to improve image resolution. In this paper, we investigate the clinical feasibility of our super-resolution ultrasound imaging method for detecting breast microcalcifications. We use our custom-built, real-time synthetic-aperture ultrasound system to acquire breast ultrasound data for 40 patients whose mammograms show the presence of breast microcalcifications. We apply our super-resolution ultrasound imaging method to the patient data, and produce clear images of breast calcifications. Our super-resolution ultrasound PC-MUSIC imaging with synthetic-aperture ultrasound data can provide a new imaging modality for detecting breast microcalcifications in clinic without using ionizing radiation.

Enhanced ultrasound for advanced diagnostics, ultrasound tomography for volume limb imaging and prosthetic fitting

NASA Astrophysics Data System (ADS)

Anthony, Brian W.

2016-04-01

Ultrasound imaging methods hold the potential to deliver low-cost, high-resolution, operator-independent and nonionizing imaging systems - such systems couple appropriate algorithms with imaging devices and techniques. The increasing demands on general practitioners motivate us to develop more usable and productive diagnostic imaging equipment. Ultrasound, specifically freehand ultrasound, is a low cost and safe medical imaging technique. It doesn't expose a patient to ionizing radiation. Its safety and versatility make it very well suited for the increasing demands on general practitioners, or for providing improved medical care in rural regions or the developing world. However it typically suffers from sonographer variability; we will discuss techniques to address user variability. We also discuss our work to combine cylindrical scanning systems with state of the art inversion algorithms to deliver ultrasound systems for imaging and quantifying limbs in 3-D in vivo. Such systems have the potential to track the progression of limb health at a low cost and without radiation exposure, as well as, improve prosthetic socket fitting. Current methods of prosthetic socket fabrication remain subjective and ineffective at creating an interface to the human body that is both comfortable and functional. Though there has been recent success using methods like magnetic resonance imaging and biomechanical modeling, a low-cost, streamlined, and quantitative process for prosthetic cup design and fabrication has not been fully demonstrated. Medical ultrasonography may inform the design process of prosthetic sockets in a more objective manner. This keynote talk presents the results of progress in this area.

Computerized mass detection in whole breast ultrasound images: reduction of false positives using bilateral subtraction technique

NASA Astrophysics Data System (ADS)

Ikedo, Yuji; Fukuoka, Daisuke; Hara, Takeshi; Fujita, Hiroshi; Takada, Etsuo; Endo, Tokiko; Morita, Takako

2007-03-01

The comparison of left and right mammograms is a common technique used by radiologists for the detection and diagnosis of masses. In mammography, computer-aided detection (CAD) schemes using bilateral subtraction technique have been reported. However, in breast ultrasonography, there are no reports on CAD schemes using comparison of left and right breasts. In this study, we propose a scheme of false positive reduction based on bilateral subtraction technique in whole breast ultrasound images. Mass candidate regions are detected by using the information of edge directions. Bilateral breast images are registered with reference to the nipple positions and skin lines. A false positive region is detected based on a comparison of the average gray values of a mass candidate region and a region with the same position and same size as the candidate region in the contralateral breast. In evaluating the effectiveness of the false positive reduction method, three normal and three abnormal bilateral pairs of whole breast images were employed. These abnormal breasts included six masses larger than 5 mm in diameter. The sensitivity was 83% (5/6) with 13.8 (165/12) false positives per breast before applying the proposed reduction method. By applying the method, false positives were reduced to 4.5 (54/12) per breast without removing a true positive region. This preliminary study indicates that the bilateral subtraction technique is effective for improving the performance of a CAD scheme in whole breast ultrasound images.

Ultrasound Imaging System Video

NASA Technical Reports Server (NTRS)

2002-01-01

In this video, astronaut Peggy Whitson uses the Human Research Facility (HRF) Ultrasound Imaging System in the Destiny Laboratory of the International Space Station (ISS) to image her own heart. The Ultrasound Imaging System provides three-dimension image enlargement of the heart and other organs, muscles, and blood vessels. It is capable of high resolution imaging in a wide range of applications, both research and diagnostic, such as Echocardiography (ultrasound of the heart), abdominal, vascular, gynecological, muscle, tendon, and transcranial ultrasound.

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

PubMed

Azhari, Haim

2012-09-01

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

High-frequency ultrasound imaging for breast cancer biopsy guidance

PubMed Central

Cummins, Thomas; Yoon, Changhan; Choi, Hojong; Eliahoo, Payam; Kim, Hyung Ham; Yamashita, Mary W.; Hovanessian-Larsen, Linda J.; Lang, Julie E.; Sener, Stephen F.; Vallone, John; Martin, Sue E.; Kirk Shung, K.

2015-01-01

Abstract. Image-guided core needle biopsy is the current gold standard for breast cancer diagnosis. Microcalcifications, an important radiographic finding on mammography suggestive of early breast cancer such as ductal carcinoma in situ, are usually biopsied under stereotactic guidance. This procedure, however, is uncomfortable for patients and requires the use of ionizing radiation. It would be preferable to biopsy microcalcifications under ultrasound guidance since it is a faster procedure, more comfortable for the patient, and requires no radiation. However, microcalcifications cannot reliably be detected with the current standard ultrasound imaging systems. This study is motivated by the clinical need for real-time high-resolution ultrasound imaging of microcalcifications, so that biopsies can be accurately performed under ultrasound guidance. We have investigated how high-frequency ultrasound imaging can enable visualization of microstructures in ex vivo breast tissue biopsy samples. We generated B-mode images of breast tissue and applied the Nakagami filtering technique to help refine image output so that microcalcifications could be better assessed during ultrasound-guided core biopsies. We describe the preliminary clinical results of high-frequency ultrasound imaging of ex vivo breast biopsy tissue with microcalcifications and without Nakagami filtering and the correlation of these images with the pathology examination by hematoxylin and eosin stain and whole slide digital scanning. PMID:26693167

Pulsed Magneto-motive Ultrasound Imaging Using Ultrasmall Magnetic Nanoprobes

PubMed Central

Mehrmohammadi, Mohammad; Oh, Junghwan; Mallidi, Srivalleesha; Emelianov, Stanislav Y.

2011-01-01

Nano-sized particles are widely regarded as a tool to study biologic events at the cellular and molecular levels. However, only some imaging modalities can visualize interaction between nanoparticles and living cells. We present a new technique, pulsed magneto-motive ultrasound imaging, which is capable of in vivo imaging of magnetic nanoparticles in real time and at sufficient depth. In pulsed magneto-motive ultrasound imaging, an external high-strength pulsed magnetic field is applied to induce the motion within the magnetically labeled tissue and ultrasound is used to detect the induced internal tissue motion. Our experiments demonstrated a sufficient contrast between normal and iron-laden cells labeled with ultrasmall magnetic nanoparticles. Therefore, pulsed magneto-motive ultrasound imaging could become an imaging tool capable of detecting magnetic nanoparticles and characterizing the cellular and molecular composition of deep-lying structures. PMID:21439255

MLESAC Based Localization of Needle Insertion Using 2D Ultrasound Images

NASA Astrophysics Data System (ADS)

Xu, Fei; Gao, Dedong; Wang, Shan; Zhanwen, A.

2018-04-01

In the 2D ultrasound image of ultrasound-guided percutaneous needle insertions, it is difficult to determine the positions of needle axis and tip because of the existence of artifacts and other noises. In this work the speckle is regarded as the noise of an ultrasound image, and a novel algorithm is presented to detect the needle in a 2D ultrasound image. Firstly, the wavelet soft thresholding technique based on BayesShrink rule is used to denoise the speckle of ultrasound image. Secondly, we add Otsu’s thresholding method and morphologic operations to pre-process the ultrasound image. Finally, the localization of the needle is identified and positioned in the 2D ultrasound image based on the maximum likelihood estimation sample consensus (MLESAC) algorithm. The experimental results show that it is valid for estimating the position of needle axis and tip in the ultrasound images with the proposed algorithm. The research work is hopeful to be used in the path planning and robot-assisted needle insertion procedures.

Ultrasound Techniques for Space Applications

NASA Technical Reports Server (NTRS)

Rooney, James A.

1985-01-01

Ultrasound has proven to be a safe non-invasive technique for imaging organs and measuring cardiovascular function. It has unique advantages for application to problems with man in space including evaluation of cardiovascular function both in serial studies and during critical operations. In addition, specialized instrumentation may be capable of detecting the onset of decompression sickness during EVA activities. A spatial location and three-dimensional reconstruction system is being developed to improve the accuracy and reproducibility for serial comparative ultrasound studies of cardiovascular function. The three-dimensional method permits the acquisition of ultrasonic images from many views that can be recombined into a single reconstruction of the heart or vasculature. In addition to conventional imaging and monitoring systems, it is sometimes necessary or desirable to develop instrumentation for special purposes. One example of this type of development is the design of a pulsed-Doppler system to monitor cerebral blood flow during critical operations such as re-entry. A second example is the design of a swept-frequency ultrasound system for the detection of bubbles in the circulatory system and/or soft tissues as an early indication of the onset of decompression sickness during EVA activities. This system exploits the resonant properties of bubbles and can detect both fundamental and second harmonic emissions from the insonified region.

[Contrast-enhanced ultrasound (CEUS) and image fusion for procedures of liver interventions].

PubMed

Jung, E M; Clevert, D A

2018-06-01

Contrast-enhanced ultrasound (CEUS) is becoming increasingly important for the detection and characterization of malignant liver lesions and allows percutaneous treatment when surgery is not possible. Contrast-enhanced ultrasound image fusion with computed tomography (CT) and magnetic resonance imaging (MRI) opens up further options for the targeted investigation of a modified tumor treatment. Ultrasound image fusion offers the potential for real-time imaging and can be combined with other cross-sectional imaging techniques as well as CEUS. With the implementation of ultrasound contrast agents and image fusion, ultrasound has been improved in the detection and characterization of liver lesions in comparison to other cross-sectional imaging techniques. In addition, this method can also be used for intervention procedures. The success rate of fusion-guided biopsies or CEUS-guided tumor ablation lies between 80 and 100% in the literature. Ultrasound-guided image fusion using CT or MRI data, in combination with CEUS, can facilitate diagnosis and therapy follow-up after liver interventions. In addition to the primary applications of image fusion in the diagnosis and treatment of liver lesions, further useful indications can be integrated into daily work. These include, for example, intraoperative and vascular applications as well applications in other organ systems.

Combined photothermal therapy and magneto-motive ultrasound imaging using multifunctional nanoparticles

NASA Astrophysics Data System (ADS)

Mehrmohammadi, Mohammad; Ma, Li L.; Chen, Yun-Sheng; Qu, Min; Joshi, Pratixa; Chen, Raeanna M.; Johnston, Keith P.; Emelianov, Stanislav

2010-02-01

Photothermal therapy is a laser-based non-invasive technique for cancer treatment. Photothermal therapy can be enhanced by employing metal nanoparticles that absorb the radiant energy from the laser leading to localized thermal damages. Targeting of nanoparticles leads to more efficient uptake and localization of photoabsorbers thus increasing the effectiveness of the treatment. Moreover, efficient targeting can reduce the required dosage of photoabsorbers; thereby reducing the side effects associated with general systematic administration of nanoparticles. Magnetic nanoparticles, due to their small size and response to an external magnetic field gradient have been proposed for targeted drug delivery. In this study, we investigate the applicability of multifunctional nanoparticles (e.g., magneto-plasmonic nanoparticles) and magneto-motive ultrasound imaging for image-guided photothermal therapy. Magneto-motive ultrasound imaging is an ultrasound based imaging technique capable of detecting magnetic nanoparticles indirectly by utilizing a high strength magnetic field to induce motion within the magnetically labeled tissue. The ultrasound imaging is used to detect the internal tissue motion. Due to presence of the magnetic component, the proposed multifunctional nanoparticles along with magneto-motive ultrasound imaging can be used to detect the presence of the photo absorbers. Clearly the higher concentration of magnetic carriers leads to a monotonic increase in magneto-motive ultrasound signal. Thus, magnetomotive ultrasound can determine the presence of the hybrid agents and provide information about their location and concentration. Furthermore, the magneto-motive ultrasound signal can indicate the change in tissue elasticity - a parameter that is expected to change significantly during the photothermal therapy. Therefore, a comprehensive guidance and assessment of the photothermal therapy may be feasible through magneto-motive ultrasound imaging and

In vivo ultrasound imaging of the bone cortex

NASA Astrophysics Data System (ADS)

Renaud, Guillaume; Kruizinga, Pieter; Cassereau, Didier; Laugier, Pascal

2018-06-01

Current clinical ultrasound scanners cannot be used to image the interior morphology of bones because these scanners fail to address the complicated physics involved for exact image reconstruction. Here, we show that if the physics is properly addressed, bone cortex can be imaged using a conventional transducer array and a programmable ultrasound scanner. We provide in vivo proof for this technique by scanning the radius and tibia of two healthy volunteers and comparing the thickness of the radius bone with high-resolution peripheral x-ray computed tomography. Our method assumes a medium that is composed of different homogeneous layers with unique elastic anisotropy and ultrasonic wave-speed values. The applicable values of these layers are found by optimizing image sharpness and intensity over a range of relevant values. In the algorithm of image reconstruction we take wave refraction between the layers into account using a ray-tracing technique. The estimated values of the ultrasonic wave-speed and anisotropy in cortical bone are in agreement with ex vivo studies reported in the literature. These parameters are of interest since they were proposed as biomarkers for cortical bone quality. In this paper we discuss the physics involved with ultrasound imaging of bone and provide an algorithm to successfully image the first segment of cortical bone.

Handheld probe integrating laser diode and ultrasound transducer array for ultrasound/photoacoustic dual modality imaging.

PubMed

Daoudi, K; van den Berg, P J; Rabot, O; Kohl, A; Tisserand, S; Brands, P; Steenbergen, W

2014-10-20

Ultrasound and photoacoustics can be utilized as complementary imaging techniques to improve clinical diagnoses. Photoacoustics provides optical contrast and functional information while ultrasound provides structural and anatomical information. As of yet, photoacoustic imaging uses large and expensive systems, which limits their clinical application and makes the combination costly and impracticable. In this work we present and evaluate a compact and ergonomically designed handheld probe, connected to a portable ultrasound system for inexpensive, real-time dual-modality ultrasound/photoacoustic imaging. The probe integrates an ultrasound transducer array and a highly efficient diode stack laser emitting 130 ns pulses at 805 nm wavelength and a pulse energy of 0.56 mJ, with a high pulse repetition frequency of up to 10 kHz. The diodes are driven by a customized laser driver, which can be triggered externally with a high temporal stability necessary to synchronize the ultrasound detection and laser pulsing. The emitted beam is collimated with cylindrical micro-lenses and shaped using a diffractive optical element, delivering a homogenized rectangular light intensity distribution. The system performance was tested in vitro and in vivo by imaging a human finger joint.

3D ultrasound imaging in image-guided intervention.

PubMed

Fenster, Aaron; Bax, Jeff; Neshat, Hamid; Cool, Derek; Kakani, Nirmal; Romagnoli, Cesare

2014-01-01

Ultrasound imaging is used extensively in diagnosis and image-guidance for interventions of human diseases. However, conventional 2D ultrasound suffers from limitations since it can only provide 2D images of 3-dimensional structures in the body. Thus, measurement of organ size is variable, and guidance of interventions is limited, as the physician is required to mentally reconstruct the 3-dimensional anatomy using 2D views. Over the past 20 years, a number of 3-dimensional ultrasound imaging approaches have been developed. We have developed an approach that is based on a mechanical mechanism to move any conventional ultrasound transducer while 2D images are collected rapidly and reconstructed into a 3D image. In this presentation, 3D ultrasound imaging approaches will be described for use in image-guided interventions.

Automatic Cataract Hardness Classification Ex Vivo by Ultrasound Techniques.

PubMed

Caixinha, Miguel; Santos, Mário; Santos, Jaime

2016-04-01

To demonstrate the feasibility of a new methodology for cataract hardness characterization and automatic classification using ultrasound techniques, different cataract degrees were induced in 210 porcine lenses. A 25-MHz ultrasound transducer was used to obtain acoustical parameters (velocity and attenuation) and backscattering signals. B-Scan and parametric Nakagami images were constructed. Ninety-seven parameters were extracted and subjected to a Principal Component Analysis. Bayes, K-Nearest-Neighbours, Fisher Linear Discriminant and Support Vector Machine (SVM) classifiers were used to automatically classify the different cataract severities. Statistically significant increases with cataract formation were found for velocity, attenuation, mean brightness intensity of the B-Scan images and mean Nakagami m parameter (p < 0.01). The four classifiers showed a good performance for healthy versus cataractous lenses (F-measure ≥ 92.68%), while for initial versus severe cataracts the SVM classifier showed the higher performance (90.62%). The results showed that ultrasound techniques can be used for non-invasive cataract hardness characterization and automatic classification. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Nonlocal means-based speckle filtering for ultrasound images

PubMed Central

Coupé, Pierrick; Hellier, Pierre; Kervrann, Charles; Barillot, Christian

2009-01-01

In image processing, restoration is expected to improve the qualitative inspection of the image and the performance of quantitative image analysis techniques. In this paper, an adaptation of the Non Local (NL-) means filter is proposed for speckle reduction in ultrasound (US) images. Originally developed for additive white Gaussian noise, we propose to use a Bayesian framework to derive a NL-means filter adapted to a relevant ultrasound noise model. Quantitative results on synthetic data show the performances of the proposed method compared to well-established and state-of-the-art methods. Results on real images demonstrate that the proposed method is able to preserve accurately edges and structural details of the image. PMID:19482578

Aptamer-conjugated nanobubbles for targeted ultrasound molecular imaging.

PubMed

Wang, Chung-Hsin; Huang, Yu-Fen; Yeh, Chih-Kuang

2011-06-07

Targeted ultrasound contrast agents can be prepared by some specific bioconjugation techniques. The biotin-avidin complex is an extremely useful noncovalent binding system, but the system might induce immunogenic side effects in human bodies. Previous proposed covalently conjugated systems suffered from low conjugation efficiency and complex procedures. In this study, we propose a covalently conjugated nanobubble coupling with nucleic acid ligands, aptamers, for providing a higher specific affinity for ultrasound targeting studies. The sgc8c aptamer was linked with nanobubbles through thiol-maleimide coupling chemistry for specific targeting to CCRF-CEM cells. Further improvements to reduce the required time and avoid the degradation of nanobubbles during conjugation procedures were also made. Several investigations were used to discuss the performance and consistency of the prepared nanobubbles, such as size distribution, conjugation efficiency analysis, and flow cytometry assay. Further, we applied our conjugated nanobubbles to ex vivo ultrasound targeted imaging and compared the resulting images with optical images. The results indicated the availability of aptamer-conjugated nanobubbles in targeted ultrasound imaging and the practicability of using a highly sensitive ultrasound system in noninvasive biological research.

The Imaging Modulography Technique Revisited for High-Definition Intravascular Ultrasound: Theoretical Framework.

PubMed

Tacheau, Antoine; Le Floc'h, Simon; Finet, Gérard; Doyley, Marvin M; Pettigrew, Roderic I; Cloutier, Guy; Ohayon, Jacques

2016-03-01

Mechanical characterization of atherosclerotic lesions remains an essential step for the detection of vulnerable plaques (VPs). Recently, an intravascular ultrasound (IVUS) elasticity reconstruction method (iMOD) has been tested in vivo by our group. The major limitation of iMOD is the need to estimate the strain field in the entire VP despite attenuated depth penetration signals when using high-definition (HD) IVUS systems. Therefore, an extended iMOD approach (E-iMOD) was designed and applied to coronary lesions of patients imaged in vivo with IVUS. The E-iMOD method (i) quantified necrotic core areas with a mean absolute relative error of 3.5 ± 3.5% and (ii) identified Young's moduli of the necrotic cores and fibrous regions with mean values of 5.7 ± 0.8 kPa and 794.5 ± 22.0 kPa instead of 5 kPa and 800 kPa, respectively. This study demonstrates the potential of the improved HD-IVUS modulography technique E-iMOD to characterize coronary VPs. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. All rights reserved.

Co-registration of ultrasound and frequency-domain photoacoustic radar images and image improvement for tumor detection

NASA Astrophysics Data System (ADS)

Dovlo, Edem; Lashkari, Bahman; Choi, Sung soo Sean; Mandelis, Andreas

2015-03-01

This paper demonstrates the co-registration of ultrasound (US) and frequency domain photoacoustic radar (FD-PAR) images with significant image improvement from applying image normalization, filtering and amplification techniques. Achieving PA imaging functionality on a commercial Ultrasound instrument could accelerate clinical acceptance and use. Experimental results presented demonstrate live animal testing and show enhancements in signal-to-noise ratio (SNR), contrast and spatial resolution. The co-registered image produced from the US and phase PA images, provides more information than both images independently.

Imaging Techniques in Endodontics: An Overview

PubMed Central

Deepak, B. S.; Subash, T. S.; Narmatha, V. J.; Anamika, T.; Snehil, T. K.; Nandini, D. B.

2012-01-01

This review provides an overview of the relevance of imaging techniques such as, computed tomography, cone beam computed tomography, and ultrasound, to endodontic practice. Many limitations of the conventional radiographic techniques have been overcome by the newer methods. Advantages and disadvantages of various imaging techniques in endodontic practice are also discussed. PMID:22530184

Ultrafast Ultrasound Imaging With Cascaded Dual-Polarity Waves.

PubMed

Zhang, Yang; Guo, Yuexin; Lee, Wei-Ning

2018-04-01

Ultrafast ultrasound imaging using plane or diverging waves, instead of focused beams, has advanced greatly the development of novel ultrasound imaging methods for evaluating tissue functions beyond anatomical information. However, the sonographic signal-to-noise ratio (SNR) of ultrafast imaging remains limited due to the lack of transmission focusing, and thus insufficient acoustic energy delivery. We hereby propose a new ultrafast ultrasound imaging methodology with cascaded dual-polarity waves (CDWs), which consists of a pulse train with positive and negative polarities. A new coding scheme and a corresponding linear decoding process were thereby designed to obtain the recovered signals with increased amplitude, thus increasing the SNR without sacrificing the frame rate. The newly designed CDW ultrafast ultrasound imaging technique achieved higher quality B-mode images than coherent plane-wave compounding (CPWC) and multiplane wave (MW) imaging in a calibration phantom, ex vivo pork belly, and in vivo human back muscle. CDW imaging shows a significant improvement in the SNR (10.71 dB versus CPWC and 7.62 dB versus MW), penetration depth (36.94% versus CPWC and 35.14% versus MW), and contrast ratio in deep regions (5.97 dB versus CPWC and 5.05 dB versus MW) without compromising other image quality metrics, such as spatial resolution and frame rate. The enhanced image qualities and ultrafast frame rates offered by CDW imaging beget great potential for various novel imaging applications.

Coregistered three-dimensional ultrasound and photoacoustic imaging system for ovarian tissue characterization

PubMed Central

Aguirre, Andres; Guo, Puyun; Gamelin, John; Yan, Shikui; Sanders, Mary M.; Brewer, Molly; Zhu, Quing

2009-01-01

Ovarian cancer has the highest mortality of all gynecologic cancers, with a five-year survival rate of only 30% or less. Current imaging techniques are limited in sensitivity and specificity in detecting early stage ovarian cancer prior to its widespread metastasis. New imaging techniques that can provide functional and molecular contrasts are needed to reduce the high mortality of this disease. One such promising technique is photoacoustic imaging. We develop a 1280-element coregistered 3-D ultrasound and photoacoustic imaging system based on a 1.75-D acoustic array. Volumetric images over a scan range of 80 deg in azimuth and 20 deg in elevation can be achieved in minutes. The system has been used to image normal porcine ovarian tissue. This is an important step toward better understanding of ovarian cancer optical properties obtained with photoacoustic techniques. To the best of our knowledge, such data are not available in the literature. We present characterization measurements of the system and compare coregistered ultrasound and photoacoustic images of ovarian tissue to histological images. The results show excellent coregistration of ultrasound and photoacoustic images. Strong optical absorption from vasculature, especially highly vascularized corpora lutea and low absorption from follicles, is demonstrated. PMID:19895116

Backscattering analysis of high frequency ultrasonic imaging for ultrasound-guided breast biopsy

NASA Astrophysics Data System (ADS)

Cummins, Thomas; Akiyama, Takahiro; Lee, Changyang; Martin, Sue E.; Shung, K. Kirk

2017-03-01

A new ultrasound-guided breast biopsy technique is proposed. The technique utilizes conventional ultrasound guidance coupled with a high frequency embedded ultrasound array located within the biopsy needle to improve the accuracy in breast cancer diagnosis.1 The array within the needle is intended to be used to detect micro- calcifications indicative of early breast cancers such as ductal carcinoma in situ (DCIS). Backscattering analysis has the potential to characterize tissues to improve localization of lesions. This paper describes initial results of the application of backscattering analysis of breast biopsy tissue specimens and shows the usefulness of high frequency ultrasound for the new biopsy related technique. Ultrasound echoes of ex-vivo breast biopsy tissue specimens were acquired by using a single-element transducer with a bandwidth from 41 MHz to 88 MHz utilizing a UBM methodology, and the backscattering coefficients were calculated. These values as well as B-mode image data were mapped in 2D and matched with each pathology image for the identification of tissue type for the comparison to the pathology images corresponding to each plane. Microcalcifications were significantly distinguished from normal tissue. Adenocarcinoma was also successfully differentiated from adipose tissue. These results indicate that backscattering analysis is able to quantitatively distinguish tissues into normal and abnormal, which should help radiologists locate abnormal areas during the proposed ultrasound-guided breast biopsy with high frequency ultrasound.

Molecular imaging with targeted contrast ultrasound.

PubMed

Piedra, Mark; Allroggen, Achim; Lindner, Jonathan R

2009-01-01

Molecular imaging with contrast-enhanced ultrasound uses targeted microbubbles that are retained in diseased tissue. The resonant properties of these microbubbles produce acoustic signals in an ultrasound field. The microbubbles are targeted to diseased tissue by using certain chemical constituents in the microbubble shell or by attaching disease-specific ligands such as antibodies to the microbubble. In this review, we discuss the applications of this technique to pathological states in the cerebrovascular system including atherosclerosis, tumor angiogenesis, ischemia, intravascular thrombus, and inflammation. Copyright 2009 S. Karger AG, Basel.

3D reconstruction of a carotid bifurcation from 2D transversal ultrasound images.

PubMed

Yeom, Eunseop; Nam, Kweon-Ho; Jin, Changzhu; Paeng, Dong-Guk; Lee, Sang-Joon

2014-12-01

Visualizing and analyzing the morphological structure of carotid bifurcations are important for understanding the etiology of carotid atherosclerosis, which is a major cause of stroke and transient ischemic attack. For delineation of vasculatures in the carotid artery, ultrasound examinations have been widely employed because of a noninvasive procedure without ionizing radiation. However, conventional 2D ultrasound imaging has technical limitations in observing the complicated 3D shapes and asymmetric vasodilation of bifurcations. This study aims to propose image-processing techniques for better 3D reconstruction of a carotid bifurcation in a rat by using 2D cross-sectional ultrasound images. A high-resolution ultrasound imaging system with a probe centered at 40MHz was employed to obtain 2D transversal images. The lumen boundaries in each transverse ultrasound image were detected by using three different techniques; an ellipse-fitting, a correlation mapping to visualize the decorrelation of blood flow, and the ellipse-fitting on the correlation map. When the results are compared, the third technique provides relatively good boundary extraction. The incomplete boundaries of arterial lumen caused by acoustic artifacts are somewhat resolved by adopting the correlation mapping and the distortion in the boundary detection near the bifurcation apex was largely reduced by using the ellipse-fitting technique. The 3D lumen geometry of a carotid artery was obtained by volumetric rendering of several 2D slices. For the 3D vasodilatation of the carotid bifurcation, lumen geometries at the contraction and expansion states were simultaneously depicted at various view angles. The present 3D reconstruction methods would be useful for efficient extraction and construction of the 3D lumen geometries of carotid bifurcations from 2D ultrasound images. Copyright © 2014 Elsevier B.V. All rights reserved.

A Sensitive TLRH Targeted Imaging Technique for Ultrasonic Molecular Imaging

PubMed Central

Hu, Xiaowen; Zheng, Hairong; Kruse, Dustin E.; Sutcliffe, Patrick; Stephens, Douglas N.; Ferrara, Katherine W.

2010-01-01

The primary goals of ultrasound molecular imaging are the detection and imaging of ultrasound contrast agents (microbubbles), which are bound to specific vascular surface receptors. Imaging methods that can sensitively and selectively detect and distinguish bound microbubbles from freely circulating microbubbles (free microbubbles) and surrounding tissue are critically important for the practical application of ultrasound contrast molecular imaging. Microbubbles excited by low frequency acoustic pulses emit wide-band echoes with a bandwidth extending beyond 20 MHz; we refer to this technique as TLRH (transmission at a low frequency and reception at a high frequency). Using this wideband, transient echo, we have developed and implemented a targeted imaging technique incorporating a multi-frequency co-linear array and the Siemens Antares® imaging system. The multi-frequency co-linear array integrates a center 5.4 MHz array, used to receive echoes and produce radiation force, and two outer 1.5 MHz arrays used to transmit low frequency incident pulses. The targeted imaging technique makes use of an acoustic radiation force sub-sequence to enhance accumulation and a TLRH imaging sub-sequence to detect bound microbubbles. The radiofrequency (RF) data obtained from the TLRH imaging sub-sequence are processsed to separate echo signatures between tissue, free microbubbles, and bound microbubbles. By imaging biotin-coated microbubbles targeted to avidin-coated cellulose tubes, we demonstrate that the proposed method has a high contrast-to-tissue ratio (up to 34 dB) and a high sensitivity to bound microbubbles (with the ratio of echoes from bound microbubbles versus free microbubbles extending up to 23 dB). The effects of the imaging pulse acoustic pressure, the radiation force sub-sequence and the use of various slow-time filters on the targeted imaging quality are studied. The TLRH targeted imaging method is demonstrated in this study to provide sensitive and selective

Ultrasound Image Despeckling Using Stochastic Distance-Based BM3D.

PubMed

Santos, Cid A N; Martins, Diego L N; Mascarenhas, Nelson D A

2017-06-01

Ultrasound image despeckling is an important research field, since it can improve the interpretability of one of the main categories of medical imaging. Many techniques have been tried over the years for ultrasound despeckling, and more recently, a great deal of attention has been focused on patch-based methods, such as non-local means and block-matching collaborative filtering (BM3D). A common idea in these recent methods is the measure of distance between patches, originally proposed as the Euclidean distance, for filtering additive white Gaussian noise. In this paper, we derive new stochastic distances for the Fisher-Tippett distribution, based on well-known statistical divergences, and use them as patch distance measures in a modified version of the BM3D algorithm for despeckling log-compressed ultrasound images. State-of-the-art results in filtering simulated, synthetic, and real ultrasound images confirm the potential of the proposed approach.

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

NASA Astrophysics Data System (ADS)

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.

Transvaginal ultrasound (image)

MedlinePlus

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

Point-of-care cardiac ultrasound techniques in the physical examination: better at the bedside.

PubMed

Kimura, Bruce J

2017-07-01

The development of hand-carried, battery-powered ultrasound devices has created a new practice in ultrasound diagnostic imaging, called 'point-of-care' ultrasound (POCUS). Capitalising on device portability, POCUS is marked by brief and limited ultrasound imaging performed by the physician at the bedside to increase diagnostic accuracy and expediency. The natural evolution of POCUS techniques in general medicine, particularly with pocket-sized devices, may be in the development of a basic ultrasound examination similar to the use of the binaural stethoscope. This paper will specifically review how POCUS improves the limited sensitivity of the current practice of traditional cardiac physical examination by both cardiologists and non-cardiologists. Signs of left ventricular systolic dysfunction, left atrial enlargement, lung congestion and elevated central venous pressures are often missed by physical techniques but can be easily detected by POCUS and have prognostic and treatment implications. Creating a general set of repetitive imaging skills for these entities for application on all patients during routine examination will standardise and reduce heterogeneity in cardiac bedside ultrasound applications, simplify teaching curricula, enhance learning and recollection, and unify competency thresholds and practice. The addition of POCUS to standard physical examination techniques in cardiovascular medicine will result in an ultrasound-augmented cardiac physical examination that reaffirms the value of bedside diagnosis. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Ultrasound Imaging of Breastfeeding--A Window to the Inside: Methodology, Normal Appearances, and Application.

PubMed

Geddes, Donna T; Sakalidis, Vanessa S

2016-05-01

Ultrasound imaging has been employed as a noninvasive technique to explore the sucking dynamics of the breastfeeding infant over the past 40 years. Recent improvements in the resolution of ultrasound images have allowed a more detailed description of the tongue movements during sucking, identification of oral structures, and measurements of nipple position and tongue motion. Several different scanning planes can be used and each show sucking from a different perspective. Ultrasound techniques and image anatomy are described in detail in this review and provide the basis for implementation in the objective assessment of breastfeeding. © The Author(s) 2016.

Assessing the Risks for Modern Diagnostic Ultrasound Imaging

NASA Astrophysics Data System (ADS)

William, Jr.

1998-05-01

Some 35 years after Paul-Jacques and Pierre Curie discovered piezoelectricity, ultrasonic imaging was developed by Paul Langevin. During this work, ultrasonic energy was observed to have a detrimental biological effect. These observations were confirmed a decade later by R. W. Wood and A. L. Loomis. It was not until the early 1950s that ultrasonic exposure conditions were controlled and specified so that studies could focus on the mechanisms by which ultrasound influenced biological materials. In the late 1940s, pioneering work was initiated to image the human body by ultrasonic techniques. These engineers and physicians were aware of the deleterious ultrasound effects at sufficiently high levels; this endeavored them to keep the exposure levels reasonably low. Over the past three decades, diagnostic ultrasound has become a sophisticated technology. Yet, our understanding of the potential risks has not changed appreciably. It is very encouraging that human injury has never been attributed to clinical practice of diagnostic ultrasound.

Handheld probe for portable high frame photoacoustic/ultrasound imaging system

NASA Astrophysics Data System (ADS)

Daoudi, K.; van den Berg, P. J.; Rabot, O.; Kohl, A.; Tisserand, S.; Brands, P.; Steenbergen, W.

2013-03-01

Photoacoustics is a hybrid imaging modality that is based on the detection of acoustic waves generated by absorption of pulsed light by tissue chromophors. In current research, this technique uses large and costly photoacoustic systems with a low frame rate imaging. To open the door for widespread clinical use, a compact, cost effective and fast system is required. In this paper we report on the development of a small compact handset pulsed laser probe which will be connected to a portable ultrasound system for real-time photoacoustic imaging and ultrasound imaging. The probe integrates diode lasers driven by an electrical driver developed for very short high power pulses. It uses specifically developed highly efficient diode stacks with high frequency repetition rate up to 10 kHz, emitting at 800nm wavelength. The emitted beam is collimated and shaped with compact micro optics beam shaping system delivering a homogenized rectangular laser beam intensity distribution. The laser block is integrated with an ultrasound transducer in an ergonomically designed handset probe. This handset is a building block enabling for a low cost high frame rate photoacoustic and ultrasound imaging system. The probe was used with a modified ultrasound scanner and was tested by imaging a tissue mimicking phantom.

Thermal dependence of ultrasound contrast agents scattering efficiency for echographic imaging techniques

NASA Astrophysics Data System (ADS)

Biagioni, Angelo; Bettucci, Andrea; Passeri, Daniele; Alippi, Adriano

2015-06-01

Ultrasound contrast agents are used in echographic imaging techniques to enhance image contrast. In addition, they may represent an interesting solution to the problem of non-invasive temperature monitoring inside the human body, based on some thermal variations of their physical properties. Contrast agents, indeed, are inserted into blood circulation and they reach the most important organs inside the human body; consequently, any thermometric property that they may possess, could be exploited for realizing a non-invasive thermometer. They essentially are a suspension of microbubbles containing a gas enclosed in a phospholipid membrane; temperature variations induce structural modifications of the microbubble phospholipid shell, thus causing thermal dependence of contrast agent's elastic characteristics. In this paper, the acoustic scattering efficiency of a bulk suspension of of SonoVue® (Bracco SpA Milan, Italy) has been studied using a pulse-echo technique in the frequency range 1-17 MHz, as it depends upon temperatures between 25 and 65°C. Experimental data confirm that the ultrasonic attenuation coefficient of SonoVue® depends on temperature between 25 and 60°C. Chemical composition of the bubble shell seem to support the hypothesis that a phase transition in the microstructure of lipid-coated microbubbles could play a key role in explaining such effect.

Musculoskeletal ultrasound: how to treat calcific tendinitis of the rotator cuff by ultrasound-guided single-needle lavage technique.

PubMed

Lee, Kenneth S; Rosas, Humberto G

2010-09-01

The purpose of this video article is to illustrate the ultrasound appearance of calcium deposition in the rotator cuff and provide a detailed step-by-step protocol for performing the ultrasound-guided single-needle lavage technique for the treatment of calcific tendinitis with emphasis on patient positioning, necessary supplies, real-time lavage technique, and steroid injection into the subacromial subdeltoid bursa. Musculoskeletal ultrasound is well established as a safe, cost-effective imaging tool in diagnosing and treating common musculoskeletal disorders. Calcific tendinitis of the rotator cuff is a common disabling cause of shoulder pain. Although most cases are self-limiting, a subset of patients is refractory to conservative therapy and requires treatment intervention. Ultrasound-guided lavage is an effective and safe minimally-invasive treatment not readily offered in the United States as an alternative to surgery, perhaps because of the limited prevalence of musculoskeletal ultrasound programs and limited training. On completion of this video article, the participant should be able to develop an appropriate diagnostic and therapeutic algorithm for the treatment of calcific tendinitis of the rotator cuff using ultrasound.

MO-AB-210-00: Diagnostic Ultrasound Imaging Quality Control and High Intensity Focused Ultrasound Therapy Hands-On Workshop

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

NONE

The goal of this ultrasound hands-on workshop is to demonstrate advancements in high intensity focused ultrasound (HIFU) and to demonstrate quality control (QC) testing in diagnostic ultrasound. HIFU is a therapeutic modality that uses ultrasound waves as carriers of energy. HIFU is used to focus a beam of ultrasound energy into a small volume at specific target locations within the body. The focused beam causes localized high temperatures and produces a well-defined regions of necrosis. This completely non-invasive technology has great potential for tumor ablation and targeted drug delivery. At the workshop, attendees will see configurations, applications, and hands-on demonstrationsmore » with on-site instructors at separate stations. The involvement of medical physicists in diagnostic ultrasound imaging service is increasing due to QC and accreditation requirements. At the workshop, an array of ultrasound testing phantoms and ultrasound scanners will be provided for attendees to learn diagnostic ultrasound QC in a hands-on environment with live demonstrations of the techniques. Target audience: Medical physicists and other medical professionals in diagnostic imaging and radiation oncology with interest in high-intensity focused ultrasound and in diagnostic ultrasound QC. Learning Objectives: Learn ultrasound physics and safety for HIFU applications through live demonstrations Get an overview of the state-of-the art in HIFU technologies and equipment Gain familiarity with common elements of a quality control program for diagnostic ultrasound imaging Identify QC tools available for testing diagnostic ultrasound systems and learn how to use these tools List of supporting vendors for HIFU and diagnostic ultrasound QC hands-on workshop: Philips Healthcare Alpinion Medical Systems Verasonics, Inc Zonare Medical Systems, Inc Computerized Imaging Reference Systems (CIRS), Inc. GAMMEX, Inc., Cablon Medical BV Steffen Sammet: NIH/NCI grant 5R25CA132822, NIH/NINDS grant

Basic physics of ultrasound imaging.

PubMed

Aldrich, John E

2007-05-01

The appearance of ultrasound images depends critically on the physical interactions of sound with the tissues in the body. The basic principles of ultrasound imaging and the physical reasons for many common artifacts are described.

Performance Evaluation of Adaptive Imaging Based on Multiphase Apodization with Cross-correlation: A Pilot Study in Abdominal Ultrasound.

PubMed

Shin, Junseob; Chen, Yu; Malhi, Harshawn; Chen, Frank; Yen, Jesse

2018-05-01

Degradation of image contrast caused by phase aberration, off-axis clutter, and reverberation clutter remains one of the most important problems in abdominal ultrasound imaging. Multiphase apodization with cross-correlation (MPAX) is a novel beamforming technique that enhances ultrasound image contrast by adaptively suppressing unwanted acoustic clutter. MPAX employs multiple pairs of complementary sinusoidal phase apodizations to intentionally introduce grating lobes that can be used to derive a weighting matrix, which mostly preserves the on-axis signals from tissue but reduces acoustic clutter contributions when multiplied with the beamformed radio-frequency (RF) signals. In this paper, in vivo performance of the MPAX technique was evaluated in abdominal ultrasound using data sets obtained from 10 human subjects referred for abdominal ultrasound at the USC Keck School of Medicine. Improvement in image contrast was quantified, first, by the contrast-to-noise ratio (CNR) and, second, by the rating of two experienced radiologists. The MPAX technique was evaluated for longitudinal and transverse views of the abdominal aorta, the inferior vena cava, the gallbladder, and the portal vein. Our in vivo results and analyses demonstrate the feasibility of the MPAX technique in enhancing image contrast in abdominal ultrasound and show potential for creating high contrast ultrasound images with improved target detectability and diagnostic confidence.

Segmentation of prostate boundaries from ultrasound images using statistical shape model.

PubMed

Shen, Dinggang; Zhan, Yiqiang; Davatzikos, Christos

2003-04-01

This paper presents a statistical shape model for the automatic prostate segmentation in transrectal ultrasound images. A Gabor filter bank is first used to characterize the prostate boundaries in ultrasound images in both multiple scales and multiple orientations. The Gabor features are further reconstructed to be invariant to the rotation of the ultrasound probe and incorporated in the prostate model as image attributes for guiding the deformable segmentation. A hierarchical deformation strategy is then employed, in which the model adaptively focuses on the similarity of different Gabor features at different deformation stages using a multiresolution technique, i.e., coarse features first and fine features later. A number of successful experiments validate the algorithm.

Ultrasound Thermal Field Imaging of Opaque Fluids

NASA Technical Reports Server (NTRS)

Andereck, C. David

1999-01-01

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

Bas-relief map using texture analysis with application to live enhancement of ultrasound images.

PubMed

Du, Huarui; Ma, Rui; Wang, Xiaoying; Zhang, Jue; Fang, Jing

2015-05-01

For ultrasound imaging, speckle is one of the most important factors in the degradation of contrast resolution because it masks meaningful texture and has the potential to interfere with diagnosis. It is expected that researchers would explore appropriate ways to reduce the speckle noise, to find the edges of structures and enhance weak borders between different organs in ultrasound imaging. Inspired by the principle of differential interference contrast microscopy, a "bas-relief map" is proposed that depicts the texture structure of ultrasound images. Based on a bas-relief map, an adaptive bas-relief filter was developed for ultrafast despeckling. Subsequently, an edge map was introduced to enhance the edges of images in real time. The holistic bas-relief map approach has been used experimentally with synthetic phantoms and digital ultrasound B-scan images of liver, kidney and gallbladder. Based on the visual inspection and the performance metrics of the despeckled images, it was found that the bas-relief map approach is capable of effectively reducing the speckle while significantly enhancing contrast and tissue boundaries for ultrasonic images, and its speckle reduction ability is comparable to that of Kuan, Lee and Frost filters. Meanwhile, the proposed technique could preserve more intra-region details compared with the popular speckle reducing anisotropic diffusion technique and more effectively enhance edges. In addition, the adaptive bas-relief filter was much less time consuming than the Kuan, Lee and Frost filter and speckle reducing anisotropic diffusion techniques. The bas-relief map strategy is effective for speckle reduction and live enhancement of ultrasound images, and can provide a valuable tool for clinical diagnosis. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

MO-AB-210-02: Ultrasound Imaging and Therapy-Hands On Workshop

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

Sammet, S.

The goal of this ultrasound hands-on workshop is to demonstrate advancements in high intensity focused ultrasound (HIFU) and to demonstrate quality control (QC) testing in diagnostic ultrasound. HIFU is a therapeutic modality that uses ultrasound waves as carriers of energy. HIFU is used to focus a beam of ultrasound energy into a small volume at specific target locations within the body. The focused beam causes localized high temperatures and produces a well-defined regions of necrosis. This completely non-invasive technology has great potential for tumor ablation and targeted drug delivery. At the workshop, attendees will see configurations, applications, and hands-on demonstrationsmore » with on-site instructors at separate stations. The involvement of medical physicists in diagnostic ultrasound imaging service is increasing due to QC and accreditation requirements. At the workshop, an array of ultrasound testing phantoms and ultrasound scanners will be provided for attendees to learn diagnostic ultrasound QC in a hands-on environment with live demonstrations of the techniques. Target audience: Medical physicists and other medical professionals in diagnostic imaging and radiation oncology with interest in high-intensity focused ultrasound and in diagnostic ultrasound QC. Learning Objectives: Learn ultrasound physics and safety for HIFU applications through live demonstrations Get an overview of the state-of-the art in HIFU technologies and equipment Gain familiarity with common elements of a quality control program for diagnostic ultrasound imaging Identify QC tools available for testing diagnostic ultrasound systems and learn how to use these tools List of supporting vendors for HIFU and diagnostic ultrasound QC hands-on workshop: Philips Healthcare Alpinion Medical Systems Verasonics, Inc Zonare Medical Systems, Inc Computerized Imaging Reference Systems (CIRS), Inc. GAMMEX, Inc., Cablon Medical BV Steffen Sammet: NIH/NCI grant 5R25CA132822, NIH/NINDS grant

MO-AB-210-01: Ultrasound Imaging and Therapy-Hands On Workshop

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

Lu, Z.

The goal of this ultrasound hands-on workshop is to demonstrate advancements in high intensity focused ultrasound (HIFU) and to demonstrate quality control (QC) testing in diagnostic ultrasound. HIFU is a therapeutic modality that uses ultrasound waves as carriers of energy. HIFU is used to focus a beam of ultrasound energy into a small volume at specific target locations within the body. The focused beam causes localized high temperatures and produces a well-defined regions of necrosis. This completely non-invasive technology has great potential for tumor ablation and targeted drug delivery. At the workshop, attendees will see configurations, applications, and hands-on demonstrationsmore » with on-site instructors at separate stations. The involvement of medical physicists in diagnostic ultrasound imaging service is increasing due to QC and accreditation requirements. At the workshop, an array of ultrasound testing phantoms and ultrasound scanners will be provided for attendees to learn diagnostic ultrasound QC in a hands-on environment with live demonstrations of the techniques. Target audience: Medical physicists and other medical professionals in diagnostic imaging and radiation oncology with interest in high-intensity focused ultrasound and in diagnostic ultrasound QC. Learning Objectives: Learn ultrasound physics and safety for HIFU applications through live demonstrations Get an overview of the state-of-the art in HIFU technologies and equipment Gain familiarity with common elements of a quality control program for diagnostic ultrasound imaging Identify QC tools available for testing diagnostic ultrasound systems and learn how to use these tools List of supporting vendors for HIFU and diagnostic ultrasound QC hands-on workshop: Philips Healthcare Alpinion Medical Systems Verasonics, Inc Zonare Medical Systems, Inc Computerized Imaging Reference Systems (CIRS), Inc. GAMMEX, Inc., Cablon Medical BV Steffen Sammet: NIH/NCI grant 5R25CA132822, NIH/NINDS grant

Improving image reconstruction of bioluminescence imaging using a priori information from ultrasound imaging (Conference Presentation)

NASA Astrophysics Data System (ADS)

Jayet, Baptiste; Ahmad, Junaid; Taylor, Shelley L.; Hill, Philip J.; Dehghani, Hamid; Morgan, Stephen P.

2017-03-01

Bioluminescence imaging (BLI) is a commonly used imaging modality in biology to study cancer in vivo in small animals. Images are generated using a camera to map the optical fluence emerging from the studied animal, then a numerical reconstruction algorithm is used to locate the sources and estimate their sizes. However, due to the strong light scattering properties of biological tissues, the resolution is very limited (around a few millimetres). Therefore obtaining accurate information about the pathology is complicated. We propose a combined ultrasound/optics approach to improve accuracy of these techniques. In addition to the BLI data, an ultrasound probe driven by a scanner is used for two main objectives. First, to obtain a pure acoustic image, which provides structural information of the sample. And second, to alter the light emission by the bioluminescent sources embedded inside the sample, which is monitored using a high speed optical detector (e.g. photomultiplier tube). We will show that this last measurement, used in conjunction with the ultrasound data, can provide accurate localisation of the bioluminescent sources. This can be used as a priori information by the numerical reconstruction algorithm, greatly increasing the accuracy of the BLI image reconstruction as compared to the image generated using only BLI data.

Intrauterine photoacoustic and ultrasound imaging probe

NASA Astrophysics Data System (ADS)

Miranda, Christopher; Barkley, Joel; Smith, Barbara S.

2018-04-01

Intrauterine photoacoustic and ultrasound imaging are probe-based imaging modalities with translational potential for use in detecting endometrial diseases. This deep-tissue imaging probe design allows for the retrofitting of commercially available endometrial sampling curettes. The imaging probe presented here has a 2.92-mm diameter and approximate length of 26 cm, which allows for entry into the human endometrial cavity, making it possible to use photoacoustic imaging and high-resolution ultrasound to characterize the uterus. We demonstrate the imaging probes' ability to provide structural information of an excised pig uterus using ultrasound imaging and detect photoacoustic signals at a radial depth of 1 cm.

Quantitative 3-d diagnostic ultrasound imaging using a modified transducer array and an automated image tracking technique.

PubMed

Hossack, John A; Sumanaweera, Thilaka S; Napel, Sandy; Ha, Jun S

2002-08-01

An approach for acquiring dimensionally accurate three-dimensional (3-D) ultrasound data from multiple 2-D image planes is presented. This is based on the use of a modified linear-phased array comprising a central imaging array that acquires multiple, essentially parallel, 2-D slices as the transducer is translated over the tissue of interest. Small, perpendicularly oriented, tracking arrays are integrally mounted on each end of the imaging transducer. As the transducer is translated in an elevational direction with respect to the central imaging array, the images obtained by the tracking arrays remain largely coplanar. The motion between successive tracking images is determined using a minimum sum of absolute difference (MSAD) image matching technique with subpixel matching resolution. An initial phantom scanning-based test of a prototype 8 MHz array indicates that linear dimensional accuracy of 4.6% (2 sigma) is achievable. This result compares favorably with those obtained using an assumed average velocity [31.5% (2 sigma) accuracy] and using an approach based on measuring image-to-image decorrelation [8.4% (2 sigma) accuracy]. The prototype array and imaging system were also tested in a clinical environment, and early results suggest that the approach has the potential to enable a low cost, rapid, screening method for detecting carotid artery stenosis. The average time for performing a screening test for carotid stenosis was reduced from an average of 45 minutes using 2-D duplex Doppler to 12 minutes using the new 3-D scanning approach.

Interference-free ultrasound imaging during HIFU therapy, using software tools

NASA Technical Reports Server (NTRS)

Vaezy, Shahram (Inventor); Held, Robert (Inventor); Sikdar, Siddhartha (Inventor); Managuli, Ravi (Inventor); Zderic, Vesna (Inventor)

2010-01-01

Disclosed herein is a method for obtaining a composite interference-free ultrasound image when non-imaging ultrasound waves would otherwise interfere with ultrasound imaging. A conventional ultrasound imaging system is used to collect frames of ultrasound image data in the presence of non-imaging ultrasound waves, such as high-intensity focused ultrasound (HIFU). The frames are directed to a processor that analyzes the frames to identify portions of the frame that are interference-free. Interference-free portions of a plurality of different ultrasound image frames are combined to generate a single composite interference-free ultrasound image that is displayed to a user. In this approach, a frequency of the non-imaging ultrasound waves is offset relative to a frequency of the ultrasound imaging waves, such that the interference introduced by the non-imaging ultrasound waves appears in a different portion of the frames.

Real-Time Intravascular Ultrasound and Photoacoustic Imaging

PubMed Central

VanderLaan, Donald; Karpiouk, Andrei; Yeager, Doug; Emelianov, Stanislav

2018-01-01

Combined intravascular ultrasound and photoacoustic imaging (IVUS/IVPA) is an emerging hybrid modality being explored as a means of improving the characterization of atherosclerotic plaque anatomical and compositional features. While initial demonstrations of the technique have been encouraging, they have been limited by catheter rotation and data acquisition, displaying and processing rates on the order of several seconds per frame as well as the use of off-line image processing. Herein, we present a complete IVUS/IVPA imaging system and method capable of real-time IVUS/IVPA imaging, with online data acquisition, image processing and display of both IVUS and IVPA images. The integrated IVUS/IVPA catheter is fully contained within a 1 mm outer diameter torque cable coupled on the proximal end to a custom-designed spindle enabling optical and electrical coupling to system hardware, including a nanosecond-pulsed laser with a controllable pulse repetition frequency capable of greater than 10kHz, motor and servo drive, an ultrasound pulser/receiver, and a 200 MHz digitizer. The system performance is characterized and demonstrated on a vessel-mimicking phantom with an embedded coronary stent intended to provide IVPA contrast within content of an IVUS image. PMID:28092507

Freehand three-dimensional ultrasound imaging of carotid artery using motion tracking technology.

PubMed

Chung, Shao-Wen; Shih, Cho-Chiang; Huang, Chih-Chung

2017-02-01

Ultrasound imaging has been extensively used for determining the severity of carotid atherosclerotic stenosis. In particular, the morphological characterization of carotid plaques can be performed for risk stratification of patients. However, using 2D ultrasound imaging for detecting morphological changes in plaques has several limitations. Due to the scan was performed on a single longitudinal cross-section, the selected 2D image is difficult to represent the entire morphology and volume of plaque and vessel lumen. In addition, the precise positions of 2D ultrasound images highly depend on the radiologists' experience, it makes the serial long-term exams of anti-atherosclerotic therapies are difficult to relocate the same corresponding planes by using 2D B-mode images. This has led to the recent development of three-dimensional (3D) ultrasound imaging, which offers improved visualization and quantification of complex morphologies of carotid plaques. In the present study, a freehand 3D ultrasound imaging technique based on optical motion tracking technology is proposed. Unlike other optical tracking systems, the marker is a small rigid body that is attached to the ultrasound probe and is tracked by eight high-performance digital cameras. The probe positions in 3D space coordinates are then calibrated at spatial and temporal resolutions of 10μm and 0.01s, respectively. The image segmentation procedure involves Otsu's and the active contour model algorithms and accurately detects the contours of the carotid arteries. The proposed imaging technique was verified using normal artery and atherosclerotic stenosis phantoms. Human experiments involving freehand scanning of the carotid artery of a volunteer were also performed. The results indicated that compared with manual segmentation, the lowest percentage errors of the proposed segmentation procedure were 7.8% and 9.1% for the external and internal carotid arteries, respectively. Finally, the effect of handshaking was

Nonlinear optical microscopy and ultrasound imaging of human cervical structure

PubMed Central

Reusch, Lisa M.; Feltovich, Helen; Carlson, Lindsey C.; Hall, Gunnsteinn; Campagnola, Paul J.; Eliceiri, Kevin W.

2013-01-01

Abstract. The cervix softens and shortens as its collagen microstructure rearranges in preparation for birth, but premature change may lead to premature birth. The global preterm birth rate has not decreased despite decades of research, likely because cervical microstructure is poorly understood. Our group has developed a multilevel approach to evaluating the human cervix. We are developing quantitative ultrasound (QUS) techniques for noninvasive interrogation of cervical microstructure and corroborating those results with high-resolution images of microstructure from second harmonic generation imaging (SHG) microscopy. We obtain ultrasound measurements from hysterectomy specimens, prepare the tissue for SHG, and stitch together several hundred images to create a comprehensive view of large areas of cervix. The images are analyzed for collagen orientation and alignment with curvelet transform, and registered with QUS data, facilitating multiscale analysis in which the micron-scale SHG images and millimeter-scale ultrasound data interpretation inform each other. This novel combination of modalities allows comprehensive characterization of cervical microstructure in high resolution. Through a detailed comparative study, we demonstrate that SHG imaging both corroborates the quantitative ultrasound measurements and provides further insight. Ultimately, a comprehensive understanding of specific microstructural cervical change in pregnancy should lead to novel approaches to the prevention of preterm birth. PMID:23412434

Nonlinear optical microscopy and ultrasound imaging of human cervical structure

NASA Astrophysics Data System (ADS)

Reusch, Lisa M.; Feltovich, Helen; Carlson, Lindsey C.; Hall, Gunnsteinn; Campagnola, Paul J.; Eliceiri, Kevin W.; Hall, Timothy J.

2013-03-01

The cervix softens and shortens as its collagen microstructure rearranges in preparation for birth, but premature change may lead to premature birth. The global preterm birth rate has not decreased despite decades of research, likely because cervical microstructure is poorly understood. Our group has developed a multilevel approach to evaluating the human cervix. We are developing quantitative ultrasound (QUS) techniques for noninvasive interrogation of cervical microstructure and corroborating those results with high-resolution images of microstructure from second harmonic generation imaging (SHG) microscopy. We obtain ultrasound measurements from hysterectomy specimens, prepare the tissue for SHG, and stitch together several hundred images to create a comprehensive view of large areas of cervix. The images are analyzed for collagen orientation and alignment with curvelet transform, and registered with QUS data, facilitating multiscale analysis in which the micron-scale SHG images and millimeter-scale ultrasound data interpretation inform each other. This novel combination of modalities allows comprehensive characterization of cervical microstructure in high resolution. Through a detailed comparative study, we demonstrate that SHG imaging both corroborates the quantitative ultrasound measurements and provides further insight. Ultimately, a comprehensive understanding of specific microstructural cervical change in pregnancy should lead to novel approaches to the prevention of preterm birth.

Application of imaging fusion combining contrast-enhanced ultrasound and magnetic resonance imaging in detection of hepatic cellular carcinomas undetectable by conventional ultrasound.

PubMed

Dong, Yi; Wang, Wen-Ping; Mao, Feng; Ji, Zheng-Biao; Huang, Bei-Jian

2016-04-01

The aim of this study is to explore the value of volume navigation image fusion-assisted contrast-enhanced ultrasound (CEUS) in detection for radiofrequency ablation guidance of hepatocellular carcinomas (HCCs), which were undetectable on conventional ultrasound. From May 2012 to May 2014, 41 patients with 49 HCCs were included in this study. All lesions were detected by dynamic magnetic resonance imaging (MRI) and planned for radiofrequency ablation but were undetectable on conventional ultrasound. After a bolus injection of 2.4 ml SonoVue® (Bracco, Italy), LOGIQ E9 ultrasound system with volume navigation system (version R1.0.5, GE Healthcare, Milwaukee, WI, USA) was used to fuse CEUS and MRI images. The fusion time, fusion success rate, lesion enhancement pattern, and detection rate were analyzed. Image fusions were conducted successfully in 49 HCCs, the technical success rate was 100%. The average fusion time was (9.2 ± 2.1) min (6-12 min). The mean diameter of HCCs was 25.2 ± 5.3 mm (mean ± SD), and mean depth was 41.8 ± 17.2 mm. The detection rate of HCCs using CEUS/MRI imaging fusion (95.9%, 47/49) was significantly higher than CEUS (42.9%, 21/49) (P < 0.05). For small HCCs (diameter, 1-2 cm), the detection rate using imaging fusion (96.9%, 32/33) was also significantly higher than CEUS (18.2%, 6/33) (P < 0.01). All HCCs displayed a rapid wash-in pattern in the arterial phase of CEUS. Imaging fusion combining CEUS and MRI is a promising technique to improve the detection, precise localization, and accurate diagnosis of undetectable HCCs on conventional ultrasound, especially small and atypical HCCs. © 2015 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.

Portable Ultrasound Imaging of the Brain for Use in Forward Battlefield Areas

DTIC Science & Technology

2011-03-01

ultrasound measurement of skull thickness and sound speed, phase correction of beam distortion, the tomographic reconstruction algorithm, and the final...produce a coherent imaging source. We propose a corrective technique that will use ultrasound-based phased -array beam correction [3], optimized...not expected to be a significant factor in the ability to phase -correct the imaging beam . In addition to planning (2.2.1), the data is also be used

Super-Resolution Image Reconstruction Applied to Medical Ultrasound

NASA Astrophysics Data System (ADS)

Ellis, Michael

vivo images of a human testicle. In all instances, the methods presented here outperform conventional image reconstruction methods by a significant margin. As TONE and its variants are general image reconstruction techniques, the theories and research presented here have the potential to significantly improve not only ultrasound's clinical utility, but that of other imaging modalities as well.

High frequency ultrasound imaging using Fabry-Perot optical etalon

NASA Astrophysics Data System (ADS)

Ashkenazi, S.; Witte, R.; O'Donnell, M.

2005-04-01

Optical detection of ultrasound provides a unique and appealing way of forming detector arrays (1D or 2D) using either raster beam scanning or simultaneous array detection exploiting wide area illumination. Etalon based optical techniques are of particular interest, due to their relatively high sensitivity resulting from multiple optical reflections within the resonance structure. Detector arrays formed by etalon based techniques are characterized by high element density and small element active area, which enables high resolution imaging at high ultrasonic frequencies (typically 10-50 MHz). In this paper we present an application of an optical etalon structure for very high frequency ultrasound detection (exceeding 100 MHz). A thin polymer Fabry-Perot etalon (10 μm thickness) has been fabricated using spin coating of polymer photoresist on a glass substrate and gold evaporation forming partially reflecting mirrors on both faces of the polymer layer. The optical resonator formed by the etalon structure has a measured Q-factor of 300. The characteristic broadband response of the optical signal was demonstrated by insonifying the etalon using two different ultrasound transducers and recording the resulting intensity modulation of optical reflection from the etalon. A focused 10 MHz transducer was used for the low MHz frequency region, and a 50 MHz focused transducer was used for the high frequency region. The optical reflection signal was compared to the pulse/echo signal detected by the same ultrasound transducer. The measured signal to noise ratio of the optically detected signal is comparable to that of the pulse/echo signal in both low and high frequency ranges. The etalon detector was integrated in a photoacoustic imaging system. High resolution images of phantom targets and biological tissue (nerve cord) were obtained. The additional information of optical absorption obtained by photoacoustic imaging, along with the high resolution detection of the etalon

Quantitative Ultrasound Imaging Using Acoustic Backscatter Coefficients.

NASA Astrophysics Data System (ADS)

Boote, Evan Jeffery

Current clinical ultrasound scanners render images which have brightness levels related to the degree of backscattered energy from the tissue being imaged. These images offer the interpreter a qualitative impression of the scattering characteristics of the tissue being examined, but due to the complex factors which affect the amplitude and character of the echoed acoustic energy, it is difficult to make quantitative assessments of scattering nature of the tissue, and thus, difficult to make precise diagnosis when subtle disease effects are present. In this dissertation, a method of data reduction for determining acoustic backscatter coefficients is adapted for use in forming quantitative ultrasound images of this parameter. In these images, the brightness level of an individual pixel corresponds to the backscatter coefficient determined for the spatial position represented by that pixel. The data reduction method utilized rigorously accounts for extraneous factors which affect the scattered echo waveform and has been demonstrated to accurately determine backscatter coefficients under a wide range of conditions. The algorithms and procedures used to form backscatter coefficient images are described. These were tested using tissue-mimicking phantoms which have regions of varying scattering levels. Another phantom has a fat-mimicking layer for testing these techniques under more clinically relevant conditions. Backscatter coefficient images were also formed of in vitro human liver tissue. A clinical ultrasound scanner has been adapted for use as a backscatter coefficient imaging platform. The digital interface between the scanner and the computer used for data reduction are described. Initial tests, using phantoms are presented. A study of backscatter coefficient imaging of in vivo liver was performed using several normal, healthy human subjects.

Thermal Imaging of Convecting Opaque Fluids using Ultrasound

NASA Technical Reports Server (NTRS)

Xu, Hongzhou; Fife, Sean; Andereck, C. David

2002-01-01

An ultrasound technique has been developed to non-intrusively image temperature fields in small-scale systems of opaque fluids undergoing convection. Fluids such as molten metals, semiconductors, and polymers are central to many industrial processes, and are often found in situations where natural convection occurs, or where thermal gradients are otherwise important. However, typical thermal and velocimetric diagnostic techniques rely upon transparency of the fluid and container, or require the addition of seed particles, or require mounting probes inside the fluid, all of which either fail altogether in opaque fluids, or necessitate significant invasion of the flow and/or modification of the walls of the container to allow access to the fluid. The idea behind our work is to use the temperature dependence of sound velocity, and the ease of propagation of ultrasound through fluids and solids, to probe the thermal fields of convecting opaque fluids non-intrusively and without the use of seed particles. The technique involves the timing of the return echoes from ultrasound pulses, a variation on an approach used previously in large-scale systems.

Despeckle filtering software toolbox for ultrasound imaging of the common carotid artery.

PubMed

Loizou, Christos P; Theofanous, Charoula; Pantziaris, Marios; Kasparis, Takis

2014-04-01

Ultrasound imaging of the common carotid artery (CCA) is a non-invasive tool used in medicine to assess the severity of atherosclerosis and monitor its progression through time. It is also used in border detection and texture characterization of the atherosclerotic carotid plaque in the CCA, the identification and measurement of the intima-media thickness (IMT) and the lumen diameter that all are very important in the assessment of cardiovascular disease (CVD). Visual perception, however, is hindered by speckle, a multiplicative noise, that degrades the quality of ultrasound B-mode imaging. Noise reduction is therefore essential for improving the visual observation quality or as a pre-processing step for further automated analysis, such as image segmentation of the IMT and the atherosclerotic carotid plaque in ultrasound images. In order to facilitate this preprocessing step, we have developed in MATLAB(®) a unified toolbox that integrates image despeckle filtering (IDF), texture analysis and image quality evaluation techniques to automate the pre-processing and complement the disease evaluation in ultrasound CCA images. The proposed software, is based on a graphical user interface (GUI) and incorporates image normalization, 10 different despeckle filtering techniques (DsFlsmv, DsFwiener, DsFlsminsc, DsFkuwahara, DsFgf, DsFmedian, DsFhmedian, DsFad, DsFnldif, DsFsrad), image intensity normalization, 65 texture features, 15 quantitative image quality metrics and objective image quality evaluation. The software is publicly available in an executable form, which can be downloaded from http://www.cs.ucy.ac.cy/medinfo/. It was validated on 100 ultrasound images of the CCA, by comparing its results with quantitative visual analysis performed by a medical expert. It was observed that the despeckle filters DsFlsmv, and DsFhmedian improved image quality perception (based on the expert's assessment and the image texture and quality metrics). It is anticipated that the

Co-registered photoacoustic, thermoacoustic, and ultrasound mouse imaging

NASA Astrophysics Data System (ADS)

Reinecke, Daniel R.; Kruger, Robert A.; Lam, Richard B.; DelRio, Stephen P.

2010-02-01

We have constructed and tested a prototype test bed that allows us to form 3D photoacoustic CT images using near-infrared (NIR) irradiation (700 - 900 nm), 3D thermoacoustic CT images using microwave irradiation (434 MHz), and 3D ultrasound images from a commercial ultrasound scanner. The device utilizes a vertically oriented, curved array to capture the photoacoustic and thermoacoustic data. In addition, an 8-MHz linear array fixed in a horizontal position provides the ultrasound data. The photoacoustic and thermoacoustic data sets are co-registered exactly because they use the same detector. The ultrasound data set requires only simple corrections to co-register its images. The photoacoustic, thermoacoustic, and ultrasound images of mouse anatomy reveal complementary anatomic information as they exploit different contrast mechanisms. The thermoacoustic images differentiate between muscle, fat and bone. The photoacoustic images reveal the hemoglobin distribution, which is localized predominantly in the vascular space. The ultrasound images provide detailed information about the bony structures. Superposition of all three images onto a co-registered hybrid image shows the potential of a trimodal photoacoustic-thermoacoustic-ultrasound small-animal imaging system.

Passive cavitation imaging with ultrasound arrays

PubMed Central

Salgaonkar, Vasant A.; Datta, Saurabh; Holland, Christy K.; Mast, T. Douglas

2009-01-01

A method is presented for passive imaging of cavitational acoustic emissions using an ultrasound array, with potential application in real-time monitoring of ultrasound ablation. To create such images, microbubble emissions were passively sensed by an imaging array and dynamically focused at multiple depths. In this paper, an analytic expression for a passive image is obtained by solving the Rayleigh–Sommerfield integral, under the Fresnel approximation, and passive images were simulated. A 192-element array was used to create passive images, in real time, from 520-kHz ultrasound scattered by a 1-mm steel wire. Azimuthal positions of this target were accurately estimated from the passive images. Next, stable and inertial cavitation was passively imaged in saline solution sonicated at 520 kHz. Bubble clusters formed in the saline samples were consistently located on both passive images and B-scans. Passive images were also created using broadband emissions from bovine liver sonicated at 2.2 MHz. Agreement was found between the images and source beam shape, indicating an ability to map therapeutic ultrasound beams in situ. The relation between these broadband emissions, sonication amplitude, and exposure conditions are discussed. PMID:20000921

Passive cavitation imaging with ultrasound arrays.

PubMed

Salgaonkar, Vasant A; Datta, Saurabh; Holland, Christy K; Mast, T Douglas

2009-12-01

A method is presented for passive imaging of cavitational acoustic emissions using an ultrasound array, with potential application in real-time monitoring of ultrasound ablation. To create such images, microbubble emissions were passively sensed by an imaging array and dynamically focused at multiple depths. In this paper, an analytic expression for a passive image is obtained by solving the Rayleigh-Sommerfield integral, under the Fresnel approximation, and passive images were simulated. A 192-element array was used to create passive images, in real time, from 520-kHz ultrasound scattered by a 1-mm steel wire. Azimuthal positions of this target were accurately estimated from the passive images. Next, stable and inertial cavitation was passively imaged in saline solution sonicated at 520 kHz. Bubble clusters formed in the saline samples were consistently located on both passive images and B-scans. Passive images were also created using broadband emissions from bovine liver sonicated at 2.2 MHz. Agreement was found between the images and source beam shape, indicating an ability to map therapeutic ultrasound beams in situ. The relation between these broadband emissions, sonication amplitude, and exposure conditions are discussed.

Stable phantom materials for ultrasound and optical imaging.

PubMed

Cabrelli, Luciana C; Pelissari, Pedro I B G B; Deana, Alessandro M; Carneiro, Antonio A O; Pavan, Theo Z

2017-01-21

Phantoms mimicking the specific properties of biological tissues are essential to fully characterize medical devices. Water-based materials are commonly used to manufacture phantoms for ultrasound and optical imaging techniques. However, these materials have disadvantages, such as easy degradation and low temporal stability. In this study, we propose an oil-based new tissue-mimicking material for ultrasound and optical imaging, with the advantage of presenting low temporal degradation. A styrene-ethylene/butylene-styrene (SEBS) copolymer in mineral oil samples was made varying the SEBS concentration between 5%-15%, and low-density polyethylene (LDPE) between 0%-9%. Acoustic properties, such as the speed of sound and the attenuation coefficient, were obtained using frequencies ranging from 1-10 MHz, and were consistent with that of soft tissues. These properties were controlled varying SEBS and LDPE concentration. To characterize the optical properties of the samples, the diffuse reflectance and transmittance were measured. Scattering and absorption coefficients ranging from 400 nm-1200 nm were calculated for each compound. SEBS gels are a translucent material presenting low optical absorption and scattering coefficients in the visible region of the spectrum, but the presence of LDPE increased the turbidity. Adding LDPE increased the absorption and scattering of the phantom materials. Ultrasound and photoacoustic images of a heterogeneous phantom made of LDPE/SEBS containing a spherical inclusion were obtained. Annatto dye was added to the inclusion to enhance the optical absorbance. The results suggest that copolymer gels are promising for ultrasound and optical imaging, making them also potentially useful for photoacoustic imaging.

Stable phantom materials for ultrasound and optical imaging

NASA Astrophysics Data System (ADS)

Cabrelli, Luciana C.; Pelissari, Pedro I. B. G. B.; Deana, Alessandro M.; Carneiro, Antonio A. O.; Pavan, Theo Z.

2017-01-01

Phantoms mimicking the specific properties of biological tissues are essential to fully characterize medical devices. Water-based materials are commonly used to manufacture phantoms for ultrasound and optical imaging techniques. However, these materials have disadvantages, such as easy degradation and low temporal stability. In this study, we propose an oil-based new tissue-mimicking material for ultrasound and optical imaging, with the advantage of presenting low temporal degradation. A styrene-ethylene/butylene-styrene (SEBS) copolymer in mineral oil samples was made varying the SEBS concentration between 5%-15%, and low-density polyethylene (LDPE) between 0%-9%. Acoustic properties, such as the speed of sound and the attenuation coefficient, were obtained using frequencies ranging from 1-10 MHz, and were consistent with that of soft tissues. These properties were controlled varying SEBS and LDPE concentration. To characterize the optical properties of the samples, the diffuse reflectance and transmittance were measured. Scattering and absorption coefficients ranging from 400 nm-1200 nm were calculated for each compound. SEBS gels are a translucent material presenting low optical absorption and scattering coefficients in the visible region of the spectrum, but the presence of LDPE increased the turbidity. Adding LDPE increased the absorption and scattering of the phantom materials. Ultrasound and photoacoustic images of a heterogeneous phantom made of LDPE/SEBS containing a spherical inclusion were obtained. Annatto dye was added to the inclusion to enhance the optical absorbance. The results suggest that copolymer gels are promising for ultrasound and optical imaging, making them also potentially useful for photoacoustic imaging.

A Flexible Annular-Array Imaging Platform for Micro-Ultrasound

PubMed Central

Qiu, Weibao; Yu, Yanyan; Chabok, Hamid Reza; Liu, Cheng; Tsang, Fu Keung; Zhou, Qifa; Shung, K. Kirk; Zheng, Hairong; Sun, Lei

2013-01-01

Micro-ultrasound is an invaluable imaging tool for many clinical and preclinical applications requiring high resolution (approximately several tens of micrometers). Imaging systems for micro-ultrasound, including single-element imaging systems and linear-array imaging systems, have been developed extensively in recent years. Single-element systems are cheaper, but linear-array systems give much better image quality at a higher expense. Annular-array-based systems provide a third alternative, striking a balance between image quality and expense. This paper presents the development of a novel programmable and real-time annular-array imaging platform for micro-ultrasound. It supports multi-channel dynamic beamforming techniques for large-depth-of-field imaging. The major image processing algorithms were achieved by a novel field-programmable gate array technology for high speed and flexibility. Real-time imaging was achieved by fast processing algorithms and high-speed data transfer interface. The platform utilizes a printed circuit board scheme incorporating state-of-the-art electronics for compactness and cost effectiveness. Extensive tests including hardware, algorithms, wire phantom, and tissue mimicking phantom measurements were conducted to demonstrate good performance of the platform. The calculated contrast-to-noise ratio (CNR) of the tissue phantom measurements were higher than 1.2 in the range of 3.8 to 8.7 mm imaging depth. The platform supported more than 25 images per second for real-time image acquisition. The depth-of-field had about 2.5-fold improvement compared to single-element transducer imaging. PMID:23287923

Developing High-Frequency Quantitative Ultrasound Techniques to Characterize Three-Dimensional Engineered Tissues

NASA Astrophysics Data System (ADS)

Mercado, Karla Patricia E.

Tissue engineering holds great promise for the repair or replacement of native tissues and organs. Further advancements in the fabrication of functional engineered tissues are partly dependent on developing new and improved technologies to monitor the properties of engineered tissues volumetrically, quantitatively, noninvasively, and nondestructively over time. Currently, engineered tissues are evaluated during fabrication using histology, biochemical assays, and direct mechanical tests. However, these techniques destroy tissue samples and, therefore, lack the capability for real-time, longitudinal monitoring. The research reported in this thesis developed nondestructive, noninvasive approaches to characterize the structural, biological, and mechanical properties of 3-D engineered tissues using high-frequency quantitative ultrasound and elastography technologies. A quantitative ultrasound technique, using a system-independent parameter known as the integrated backscatter coefficient (IBC), was employed to visualize and quantify structural properties of engineered tissues. Specifically, the IBC was demonstrated to estimate cell concentration and quantitatively detect differences in the microstructure of 3-D collagen hydrogels. Additionally, the feasibility of an ultrasound elastography technique called Single Tracking Location Acoustic Radiation Force Impulse (STL-ARFI) imaging was demonstrated for estimating the shear moduli of 3-D engineered tissues. High-frequency ultrasound techniques can be easily integrated into sterile environments necessary for tissue engineering. Furthermore, these high-frequency quantitative ultrasound techniques can enable noninvasive, volumetric characterization of the structural, biological, and mechanical properties of engineered tissues during fabrication and post-implantation.

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

PubMed Central

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

2012-01-01

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

Detecting stripe artifacts in ultrasound images.

PubMed

Maciak, Adam; Kier, Christian; Seidel, Günter; Meyer-Wiethe, Karsten; Hofmann, Ulrich G

2009-10-01

Brain perfusion diseases such as acute ischemic stroke are detectable through computed tomography (CT)-/magnetic resonance imaging (MRI)-based methods. An alternative approach makes use of ultrasound imaging. In this low-cost bedside method, noise and artifacts degrade the imaging process. Especially stripe artifacts show a similar signal behavior compared to acute stroke or brain perfusion diseases. This document describes how stripe artifacts can be detected and eliminated in ultrasound images obtained through harmonic imaging (HI). On the basis of this new method, both proper identification of areas with critically reduced brain tissue perfusion and classification between brain perfusion defects and ultrasound stripe artifacts are made possible.

GPU-Based Simulation of Ultrasound Imaging Artifacts for Cryosurgery Training.

PubMed

Keelan, Robert; Shimada, Kenji; Rabin, Yoed

2017-02-01

This study presents an efficient computational technique for the simulation of ultrasound imaging artifacts associated with cryosurgery based on nonlinear ray tracing. This study is part of an ongoing effort to develop computerized training tools for cryosurgery, with prostate cryosurgery as a development model. The capability of performing virtual cryosurgical procedures on a variety of test cases is essential for effective surgical training. Simulated ultrasound imaging artifacts include reverberation and reflection of the cryoprobes in the unfrozen tissue, reflections caused by the freezing front, shadowing caused by the frozen region, and tissue property changes in repeated freeze-thaw cycles procedures. The simulated artifacts appear to preserve the key features observed in a clinical setting. This study displays an example of how training may benefit from toggling between the undisturbed ultrasound image, the simulated temperature field, the simulated imaging artifacts, and an augmented hybrid presentation of the temperature field superimposed on the ultrasound image. The proposed method is demonstrated on a graphic processing unit at 100 frames per second, on a mid-range personal workstation, at two orders of magnitude faster than a typical cryoprocedure. This performance is based on computation with C++ accelerated massive parallelism and its interoperability with the DirectX-rendering application programming interface.

GPU-Based Simulation of Ultrasound Imaging Artifacts for Cryosurgery Training

PubMed Central

Keelan, Robert; Shimada, Kenji

2016-01-01

This study presents an efficient computational technique for the simulation of ultrasound imaging artifacts associated with cryosurgery based on nonlinear ray tracing. This study is part of an ongoing effort to develop computerized training tools for cryosurgery, with prostate cryosurgery as a development model. The capability of performing virtual cryosurgical procedures on a variety of test cases is essential for effective surgical training. Simulated ultrasound imaging artifacts include reverberation and reflection of the cryoprobes in the unfrozen tissue, reflections caused by the freezing front, shadowing caused by the frozen region, and tissue property changes in repeated freeze–thaw cycles procedures. The simulated artifacts appear to preserve the key features observed in a clinical setting. This study displays an example of how training may benefit from toggling between the undisturbed ultrasound image, the simulated temperature field, the simulated imaging artifacts, and an augmented hybrid presentation of the temperature field superimposed on the ultrasound image. The proposed method is demonstrated on a graphic processing unit at 100 frames per second, on a mid-range personal workstation, at two orders of magnitude faster than a typical cryoprocedure. This performance is based on computation with C++ accelerated massive parallelism and its interoperability with the DirectX-rendering application programming interface. PMID:26818026

Plantar fascia segmentation and thickness estimation in ultrasound images.

PubMed

Boussouar, Abdelhafid; Meziane, Farid; Crofts, Gillian

2017-03-01

Ultrasound (US) imaging offers significant potential in diagnosis of plantar fascia (PF) injury and monitoring treatment. In particular US imaging has been shown to be reliable in foot and ankle assessment and offers a real-time effective imaging technique that is able to reliably confirm structural changes, such as thickening, and identify changes in the internal echo structure associated with diseased or damaged tissue. Despite the advantages of US imaging, images are difficult to interpret during medical assessment. This is partly due to the size and position of the PF in relation to the adjacent tissues. It is therefore a requirement to devise a system that allows better and easier interpretation of PF ultrasound images during diagnosis. This study proposes an automatic segmentation approach which for the first time extracts ultrasound data to estimate size across three sections of the PF (rearfoot, midfoot and forefoot). This segmentation method uses artificial neural network module (ANN) in order to classify small overlapping patches as belonging or not-belonging to the region of interest (ROI) of the PF tissue. Features ranking and selection techniques were performed as a post-processing step for features extraction to reduce the dimension and number of the extracted features. The trained ANN classifies the image overlapping patches into PF and non-PF tissue, and then it is used to segment the desired PF region. The PF thickness was calculated using two different methods: distance transformation and area-length calculation algorithms. This new approach is capable of accurately segmenting the PF region, differentiating it from surrounding tissues and estimating its thickness. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

[Abdominal ultrasound course an introduction to the ultrasound technique. Physical basis. Ultrasound language].

PubMed

Segura-Grau, A; Sáez-Fernández, A; Rodríguez-Lorenzo, A; Díaz-Rodríguez, N

2014-01-01

Ultrasound is a non-invasive, accessible, and versatile diagnostic technique that uses high frequency ultrasound waves to define outline the organs of the human body, with no ionising radiation, in real time and with the capacity to visual several planes. The high diagnostic yield of the technique, together with its ease of uses plus the previously mentioned characteristics, has currently made it a routine method in daily medical practice. It is for this reason that the multidisciplinary character of this technique is being strengthened every day. To be able to perform the technique correctly requires knowledge of the physical basis of ultrasound, the method and the equipment, as well as of the human anatomy, in order to have the maximum information possible to avoid diagnostic errors due to poor interpretation or lack of information. Copyright © 2013 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España. All rights reserved.

Ultrasound imaging of the mouse pancreatic duct using lipid microbubbles

NASA Astrophysics Data System (ADS)

Banerjee, B.; McKeown, K. R.; Skovan, B.; Ogram, E.; Ingram, P.; Ignatenko, N.; Paine-Murrieta, G.; Witte, R.; Matsunaga, T. O.

2012-03-01

Research requiring the murine pancreatic duct to be imaged is often challenging due to the difficulty in selectively cannulating the pancreatic duct. We have successfully catheterized the pancreatic duct through the common bile duct in severe combined immune deficient (SCID) mice and imaged the pancreatic duct with gas filled lipid microbubbles that increase ultrasound imaging sensitivity due to exquisite scattering at the gas/liquid interface. A SCID mouse was euthanized by CO2, a midline abdominal incision made, the common bile duct cut at its midpoint, a 2 cm, 32 gauge tip catheter was inserted about 1 mm into the duct and tied with suture. The duodenum and pancreas were excised, removed in toto, embedded in agar and an infusion pump was used to instill normal saline or lipid-coated microbubbles (10 million / ml) into the duct. B-mode images before and after infusion of the duct with microbubbles imaged the entire pancreatic duct (~ 1 cm) with high contrast. The microbubbles were cavitated by high mechanical index (HMI) ultrasound for imaging to be repeated. Our technique of catheterization and using lipid microbubbles as a contrast agent may provide an effective, affordable technique of imaging the murine pancreatic duct; cavitation with HMI ultrasound would enable repeated imaging to be performed and clustering of targeted microbubbles to receptors on ductal cells would allow pathology to be localized accurately. This research was supported by the Experimental Mouse Shared Service of the AZ Cancer Center (Grant Number P30CA023074, NIH/NCI and the GI SPORE (NIH/NCI P50 CA95060).

Estimation of bladder wall location in ultrasound images.

PubMed

Topper, A K; Jernigan, M E

1991-05-01

A method of automatically estimating the location of the bladder wall in ultrasound images is proposed. Obtaining this estimate is intended to be the first stage in the development of an automatic bladder volume calculation system. The first step in the bladder wall estimation scheme involves globally processing the images using standard image processing techniques to highlight the bladder wall. Separate processing sequences are required to highlight the anterior bladder wall and the posterior bladder wall. The sequence to highlight the anterior bladder wall involves Gaussian smoothing and second differencing followed by zero-crossing detection. Median filtering followed by thresholding and gradient detection is used to highlight as much of the rest of the bladder wall as was visible in the original images. Then a 'bladder wall follower'--a line follower with rules based on the characteristics of ultrasound imaging and the anatomy involved--is applied to the processed images to estimate the bladder wall location by following the portions of the bladder wall which are highlighted and filling in the missing segments. The results achieved using this scheme are presented.

Navigational ultrasound imaging: A novel imaging tool for aiding interventional therapies of equine musculoskeletal injuries.

PubMed

Lustgarten, M; Redding, W R; Schnabel, L V; Prange, T; Seiler, G S

2016-03-01

Navigational ultrasound imaging, also known as fusion imaging, is a novel technology that allows real-time ultrasound imaging to be correlated with a previously acquired computed tomography (CT) or magnetic resonance imaging (MRI) study. It has been used in man to aid interventional therapies and has been shown to be valuable for sampling and assessing lesions diagnosed with MRI or CT that are equivocal on ultrasonography. To date, there are no reports of the use of this modality in veterinary medicine. To assess whether navigational ultrasound imaging can be used to assist commonly performed interventional therapies for the treatment of equine musculoskeletal injuries diagnosed with MRI and determine the appropriateness of regional anatomical landmarks as registration sites. Retrospective, descriptive clinical study. Horses with musculoskeletal injuries of the distal limb diagnosed with MRI scheduled for ultrasound-guided interventional therapies were evaluated (n = 17 horses with a total of 29 lesions). Anatomical landmarks used for image registration for the navigational procedure were documented. Accuracy of lesion location and success of the procedure were assessed subjectively and described using a grading scale. All procedures were accurately registered using regional anatomical landmarks and considered successful based on our criteria. Anatomical landmarks were described for each lesion type. The addition of navigational imaging was considered to greatly aid the procedures in 59% of cases and added information to the remainder of the procedures. The technique was considered to improve the precision of these interventional procedures. Navigational ultrasound imaging is a complementary imaging modality that can be used for the treatment of equine soft tissue musculoskeletal injuries diagnosed with MRI. © 2015 EVJ Ltd.

Pulsed magneto-motive ultrasound imaging to detect intracellular trafficking of magnetic nanoparticles

PubMed Central

Mehrmohamamdi, Mohammad; Qu, Min; Ma, Li L.; Romanovicz, Dwight K.; Johnston, Keith P.; Sokolov, Konstantin V.; Emelianov, Stanislav Y.

2012-01-01

As applications of nanoparticles in medical imaging and biomedicine rapidly expand, the interactions of nanoparticles with living cells have become an area of active interest. For example, intracellular trafficking of nanoparticles – an important part of cell-nanoparticle interaction, has been well studied using plasmonic nanoparticles and optical or optics-based techniques due to the change in optical properties of the nanoparticle aggregates. However, magnetic nanoparticles, despite their wide range of clinical applications, do not exhibit plasmonic-resonant properties and therefore their intracellular aggregation cannot be detected by optics-based imaging techniques. In this study, we investigated the feasibility of a novel imaging technique – pulsed magneto-motive ultrasound (pMMUS), to identify intracellular trafficking of endocytosed magnetic nanoparticles. In pulsed magneto-motive ultrasound imaging a focused, high intensity, pulsed magnetic field is used to excite the cells labeled with magnetic nanoparticles, and ultrasound imaging is then used to monitor the mechanical response of the tissue. We demonstrated previously that clusters of magnetic nanoparticles amplify the pMMUS signal in comparison to signal from individual nanoparticles. Here we further demonstrate that pMMUS imaging can identify interaction between magnetic nanoparticles and living cells, i.e. intracellular aggregation of nanoparticles within the cells. The results of our study suggest that pMMUS imaging can not only detect the presence of magnetic nanoparticles but also provides information about their intracellular trafficking non-invasively and in real-time. PMID:21926454

An open access thyroid ultrasound image database

NASA Astrophysics Data System (ADS)

Pedraza, Lina; Vargas, Carlos; Narváez, Fabián.; Durán, Oscar; Muñoz, Emma; Romero, Eduardo

2015-01-01

Computer aided diagnosis systems (CAD) have been developed to assist radiologists in the detection and diagnosis of abnormalities and a large number of pattern recognition techniques have been proposed to obtain a second opinion. Most of these strategies have been evaluated using different datasets making their performance incomparable. In this work, an open access database of thyroid ultrasound images is presented. The dataset consists of a set of B-mode Ultrasound images, including a complete annotation and diagnostic description of suspicious thyroid lesions by expert radiologists. Several types of lesions as thyroiditis, cystic nodules, adenomas and thyroid cancers were included while an accurate lesion delineation is provided in XML format. The diagnostic description of malignant lesions was confirmed by biopsy. The proposed new database is expected to be a resource for the community to assess different CAD systems.

Comparison of ultrasound B-mode, strain imaging, acoustic radiation force impulse displacement and shear wave velocity imaging using real time clinical breast images

NASA Astrophysics Data System (ADS)

Manickam, Kavitha; Machireddy, Ramasubba Reddy; Raghavan, Bagyam

2016-04-01

It has been observed that many pathological process increase the elastic modulus of soft tissue compared to normal. In order to image tissue stiffness using ultrasound, a mechanical compression is applied to tissues of interest and local tissue deformation is measured. Based on the mechanical excitation, ultrasound stiffness imaging methods are classified as compression or strain imaging which is based on external compression and Acoustic Radiation Force Impulse (ARFI) imaging which is based on force generated by focused ultrasound. When ultrasound is focused on tissue, shear wave is generated in lateral direction and shear wave velocity is proportional to stiffness of tissues. The work presented in this paper investigates strain elastography and ARFI imaging in clinical cancer diagnostics using real time patient data. Ultrasound B-mode imaging, strain imaging, ARFI displacement and ARFI shear wave velocity imaging were conducted on 50 patients (31 Benign and 23 malignant categories) using Siemens S2000 machine. True modulus contrast values were calculated from the measured shear wave velocities. For ultrasound B-mode, ARFI displacement imaging and strain imaging, observed image contrast and Contrast to Noise Ratio were calculated for benign and malignant cancers. Observed contrast values were compared based on the true modulus contrast values calculated from shear wave velocity imaging. In addition to that, student unpaired t-test was conducted for all the four techniques and box plots are presented. Results show that, strain imaging is better for malignant cancers whereas ARFI imaging is superior than strain imaging and B-mode for benign lesions representations.

Continuous-wave ultrasound reflectometry for surface roughness imaging applications

PubMed Central

Kinnick, R. R.; Greenleaf, J. F.; Fatemi, M.

2009-01-01

Background Measurement of surface roughness irregularities that result from various sources such as manufacturing processes, surface damage, and corrosion, is an important indicator of product quality for many nondestructive testing (NDT) industries. Many techniques exist, however because of their qualitative, time-consuming and direct-contact modes, it is of some importance to work out new experimental methods and efficient tools for quantitative estimation of surface roughness. Objective and Method Here we present continuous-wave ultrasound reflectometry (CWUR) as a novel nondestructive modality for imaging and measuring surface roughness in a non-contact mode. In CWUR, voltage variations due to phase shifts in the reflected ultrasound waves are recorded and processed to form an image of surface roughness. Results An acrylic test block with surface irregularities ranging from 4.22 μm to 19.05 μm as measured by a coordinate measuring machine (CMM), is scanned by an ultrasound transducer having a diameter of 45 mm, a focal distance of 70 mm, and a central frequency of 3 MHz. It is shown that CWUR technique gives very good agreement with the results obtained through CMM inasmuch as the maximum average percent error is around 11.5%. Conclusion Images obtained here demonstrate that CWUR may be used as a powerful noncontact and quantitative tool for nondestructive inspection and imaging of surface irregularities at the micron-size level with an average error of less than 11.5%. PMID:18664399

Oil-based gel phantom for ultrasound and optical imaging

NASA Astrophysics Data System (ADS)

Cabrelli, Luciana C.; Pelissari, Pedro I. B. G. B.; Aggarwal, Lucimara P.; Deana, Alessandro M.; Carneiro, Antonio A. O.; Pavan, Theo. Z.

2015-06-01

Water-based materials are commonly used in phantoms for ultrasound and optical imaging techniques. However, these materials have disadvantages such as easy degradation and low temporal stability. In this study, we propose an oil-based new tissue mimicking material for ultrasound and optical imaging, with the advantage of presenting low temporal degradation. Styrene-Ethylene/Butylene-Styrene (SEBS) copolymer in mineral oil samples were made varying the SEBS concentration between 5-15%, and low-density polyethylene (LDPE) between 0-9%. Acoustic properties such as speed of sound and attenuation coefficient were obtained by the substitution technique with frequencies ranging from 2.25-10 MHz, and were consistent to that of soft tissue. These properties were controlled varying SEBS and LDPE concentration; speed of sound from 1445-1480 m/s, and attenuation from 0.86-11.31 dB/cm were observed. SEBS gels with 0% of LDPE were optically transparent, presenting low optical absorption and scattering coefficients in the visible region of the spectrum. In order to fully characterize the optical properties of the samples, the reflectances of the surfaces were measured, along with the absorption. Scattering and absorption coefficients ranging from 400 nm to 1200 nm were calculated for each compound. The results showed that the presence of LDPE increased absorption and scattering of the phantoms. The results suggest the copolymer gels are promising for ultrasound and optical imaging, what make them also potentially useful for photoacoustic imaging.

Multidimensional deconvolution of optical microscope and ultrasound imaging using adaptive least-mean-square (LMS) inverse filtering

NASA Astrophysics Data System (ADS)

Sapia, Mark Angelo

2000-11-01

Three-dimensional microscope images typically suffer from reduced resolution due to the effects of convolution, optical aberrations and out-of-focus blurring. Two- dimensional ultrasound images are also degraded by convolutional bluffing and various sources of noise. Speckle noise is a major problem in ultrasound images. In microscopy and ultrasound, various methods of digital filtering have been used to improve image quality. Several methods of deconvolution filtering have been used to improve resolution by reversing the convolutional effects, many of which are based on regularization techniques and non-linear constraints. The technique discussed here is a unique linear filter for deconvolving 3D fluorescence microscopy or 2D ultrasound images. The process is to solve for the filter completely in the spatial-domain using an adaptive algorithm to converge to an optimum solution for de-blurring and resolution improvement. There are two key advantages of using an adaptive solution: (1)it efficiently solves for the filter coefficients by taking into account all sources of noise and degraded resolution at the same time, and (2)achieves near-perfect convergence to the ideal linear deconvolution filter. This linear adaptive technique has other advantages such as avoiding artifacts of frequency-domain transformations and concurrent adaptation to suppress noise. Ultimately, this approach results in better signal-to-noise characteristics with virtually no edge-ringing. Many researchers have not adopted linear techniques because of poor convergence, noise instability and negative valued data in the results. The methods presented here overcome many of these well-documented disadvantages and provide results that clearly out-perform other linear methods and may also out-perform regularization and constrained algorithms. In particular, the adaptive solution is most responsible for overcoming the poor performance associated with linear techniques. This linear adaptive approach to

MR techniques for guiding high-intensity focused ultrasound (HIFU) treatments.

PubMed

Kuroda, Kagayaki

2018-02-01

To make full use of the ability of magnetic resonance (MR) to guide high-intensity focused ultrasound (HIFU) treatment, effort has been made to improve techniques for thermometry, motion tracking, and sound beam visualization. For monitoring rapid temperature elevation with proton resonance frequency (PRF) shift, data acquisition and processing can be accelerated with parallel imaging and/or sparse sampling in conjunction with appropriate signal processing methods. Thermometry should be robust against tissue motion, motion-induced magnetic field variation, and susceptibility change. Thus, multibaseline, referenceless, or hybrid techniques have become important. In cases with adipose or bony tissues, for which PRF shift cannot be used, thermometry with relaxation times or signal intensity may be utilized. Motion tracking is crucial not only for thermometry but also for targeting the focus of an ultrasound in moving organs such as the liver, kidney, or heart. Various techniques for motion tracking, such as those based on an anatomical image atlas with optical-flow displacement detection, a navigator echo to seize the diaphragm position, and/or rapid imaging to track vessel positions, have been proposed. Techniques for avoiding the ribcage and near-field heating have also been examined. MR acoustic radiation force imaging (MR-ARFI) is an alternative to thermometry that can identify the location and shape of the focal spot and sound beam path. This technique could be useful for treating heterogeneous tissue regions or performing transcranial therapy. All of these developments, which will be discussed further in this review, expand the applicability of HIFU treatments to a variety of clinical targets while maintaining safety and precision. 2 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2018;47:316-331. © 2017 International Society for Magnetic Resonance in Medicine.

A new imaging technique based on resonance for arterial vessels

NASA Astrophysics Data System (ADS)

Zhang, Xiaoming; Fatemi, Mostafa; Greenleaf, James F.

2003-04-01

Vibro-acoustography is a new noncontact imaging method based on the radiation force of ultrasound. We extend this technique for imaging of arterial vessels based on vibration resonance. The arterial vessel is excited remotely by ultrasound at a resonant frequency, at which the vibration of the vessel as well as its transmission to the body surface are large enough to be measured. By scanning the ultrasound beam across the vessel plane and measuring the vibration at one single point on the body or vessel surface, an image of the interior artery can be mapped. Theory is developed that predicts the measured velocity is proportional to the value of the mode shape at resonance. Experimental studies were carried out on a silicone tube embedded in a cylindrical gel phantom of large radius, which simulates a large artery and the surrounding body. The fundamental frequency was measured at which the ultrasound transducer scanned across the tube plane with velocity measurement at one single point on the tube or on the phantom by laser. The images obtained show clearly the interior tube and the modal shape of the tube. The present technique offers a new imaging method for arterial vessels.

Modulated Excitation Imaging System for Intravascular Ultrasound.

PubMed

Qiu, Weibao; Wang, Xingying; Chen, Yan; Fu, Qiang; Su, Min; Zhang, Lining; Xia, Jingjing; Dai, Jiyan; Zhang, Yaonan; Zheng, Hairong

2017-08-01

Advances in methodologies and tools often lead to new insights into cardiovascular diseases. Intravascular ultrasound (IVUS) is a well-established diagnostic method that provides high-resolution images of the vessel wall and atherosclerotic plaques. High-frequency (>50 MHz) ultrasound enables the spatial resolution of IVUS to approach that of optical imaging methods. However, the penetration depth decreases when using higher imaging frequencies due to the greater acoustic attenuation. An imaging method that improves the penetration depth of high-resolution IVUS would, therefore, be of major clinical importance. Modulated excitation imaging is known to allow ultrasound waves to penetrate further. This paper presents an ultrasound system specifically for modulated-excitation-based IVUS imaging. The system incorporates a high-voltage waveform generator and an image processing board that are optimized for IVUS applications. In addition, a miniaturized ultrasound transducer has been constructed using a Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 single crystal to improve the ultrasound characteristics. The results show that the proposed system was able to provide increases of 86.7% in penetration depth and 9.6 dB in the signal-to-noise ratio for 60 MHz IVUS. In vitro tissue samples were also investigated to demonstrate the performance of the system.

A Review on Real-Time 3D Ultrasound Imaging Technology

PubMed Central

Zeng, Zhaozheng

2017-01-01

Real-time three-dimensional (3D) ultrasound (US) has attracted much more attention in medical researches because it provides interactive feedback to help clinicians acquire high-quality images as well as timely spatial information of the scanned area and hence is necessary in intraoperative ultrasound examinations. Plenty of publications have been declared to complete the real-time or near real-time visualization of 3D ultrasound using volumetric probes or the routinely used two-dimensional (2D) probes. So far, a review on how to design an interactive system with appropriate processing algorithms remains missing, resulting in the lack of systematic understanding of the relevant technology. In this article, previous and the latest work on designing a real-time or near real-time 3D ultrasound imaging system are reviewed. Specifically, the data acquisition techniques, reconstruction algorithms, volume rendering methods, and clinical applications are presented. Moreover, the advantages and disadvantages of state-of-the-art approaches are discussed in detail. PMID:28459067

A Review on Real-Time 3D Ultrasound Imaging Technology.

PubMed

Huang, Qinghua; Zeng, Zhaozheng

2017-01-01

Real-time three-dimensional (3D) ultrasound (US) has attracted much more attention in medical researches because it provides interactive feedback to help clinicians acquire high-quality images as well as timely spatial information of the scanned area and hence is necessary in intraoperative ultrasound examinations. Plenty of publications have been declared to complete the real-time or near real-time visualization of 3D ultrasound using volumetric probes or the routinely used two-dimensional (2D) probes. So far, a review on how to design an interactive system with appropriate processing algorithms remains missing, resulting in the lack of systematic understanding of the relevant technology. In this article, previous and the latest work on designing a real-time or near real-time 3D ultrasound imaging system are reviewed. Specifically, the data acquisition techniques, reconstruction algorithms, volume rendering methods, and clinical applications are presented. Moreover, the advantages and disadvantages of state-of-the-art approaches are discussed in detail.

Ultrasound image edge detection based on a novel multiplicative gradient and Canny operator.

PubMed

Zheng, Yinfei; Zhou, Yali; Zhou, Hao; Gong, Xiaohong

2015-07-01

To achieve the fast and accurate segmentation of ultrasound image, a novel edge detection method for speckle noised ultrasound images was proposed, which was based on the traditional Canny and a novel multiplicative gradient operator. The proposed technique combines a new multiplicative gradient operator of non-Newtonian type with the traditional Canny operator to generate the initial edge map, which is subsequently optimized by the following edge tracing step. To verify the proposed method, we compared it with several other edge detection methods that had good robustness to noise, with experiments on the simulated and in vivo medical ultrasound image. Experimental results showed that the proposed algorithm has higher speed for real-time processing, and the edge detection accuracy could be 75% or more. Thus, the proposed method is very suitable for fast and accurate edge detection of medical ultrasound images. © The Author(s) 2014.

Wavelet median denoising of ultrasound images

NASA Astrophysics Data System (ADS)

Macey, Katherine E.; Page, Wyatt H.

2002-05-01

Ultrasound images are contaminated with both additive and multiplicative noise, which is modeled by Gaussian and speckle noise respectively. Distinguishing small features such as fallopian tubes in the female genital tract in the noisy environment is problematic. A new method for noise reduction, Wavelet Median Denoising, is presented. Wavelet Median Denoising consists of performing a standard noise reduction technique, median filtering, in the wavelet domain. The new method is tested on 126 images, comprised of 9 original images each with 14 levels of Gaussian or speckle noise. Results for both separable and non-separable wavelets are evaluated, relative to soft-thresholding in the wavelet domain, using the signal-to-noise ratio and subjective assessment. The performance of Wavelet Median Denoising is comparable to that of soft-thresholding. Both methods are more successful in removing Gaussian noise than speckle noise. Wavelet Median Denoising outperforms soft-thresholding for a larger number of cases of speckle noise reduction than of Gaussian noise reduction. Noise reduction is more successful using non-separable wavelets than separable wavelets. When both methods are applied to ultrasound images obtained from a phantom of the female genital tract a small improvement is seen; however, a substantial improvement is required prior to clinical use.

Automatic Contour Tracking in Ultrasound Images

ERIC Educational Resources Information Center

Li, Min; Kambhamettu, Chandra; Stone, Maureen

2005-01-01

In this paper, a new automatic contour tracking system, EdgeTrak, for the ultrasound image sequences of human tongue is presented. The images are produced by a head and transducer support system (HATS). The noise and unrelated high-contrast edges in ultrasound images make it very difficult to automatically detect the correct tongue surfaces. In…

Recent technological advancements in cardiac ultrasound imaging.

PubMed

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

2018-03-01

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

Optical Detection of Ultrasound in Photoacoustic Imaging

PubMed Central

Dong, Biqin; Sun, Cheng; Zhang, Hao F.

2017-01-01

Objective Photoacoustic (PA) imaging emerges as a unique tool to study biological samples based on optical absorption contrast. In PA imaging, piezoelectric transducers are commonly used to detect laser-induced ultrasonic waves. However, they typically lack adequate broadband sensitivity at ultrasonic frequency higher than 100 MHz while their bulky size and optically opaque nature cause technical difficulties in integrating PA imaging with conventional optical imaging modalities. To overcome these limitations, optical methods of ultrasound detection were developed and shown their unique applications in photoacoustic imaging. Methods We provide an overview of recent technological advances in optical methods of ultrasound detection and their applications in PA imaging. A general theoretical framework describing sensitivity, bandwidth, and angular responses of optical ultrasound detection is also introduced. Results Optical methods of ultrasound detection can provide improved detection angle and sensitivity over significantly extended bandwidth. In addition, its versatile variants also offer additional advantages, such as device miniaturization, optical transparency, mechanical flexibility, minimal electrical/mechanical crosstalk, and potential noncontact PA imaging. Conclusion The optical ultrasound detection methods discussed in this review and their future evolution may play an important role in photoacoustic imaging for biomedical study and clinical diagnosis. PMID:27608445

Ultrasound contrast agent fabricated from microbubbles containing instant adhesives, and its ultrasound imaging ability

NASA Astrophysics Data System (ADS)

Makuta, T.; Tamakawa, Y.

2012-04-01

Non-invasive surgery techniques and drug delivery system with acoustic characteristics of ultrasound contrast agent have been studied intensively in recent years. Ultrasound contrast agent collapses easily under the blood circulating and the ultrasound irradiating because it is just a stabilized bubble without solid-shell by surface adsorption of surfactant or lipid. For improving the imaging stability, we proposed the fabrication method of the hollow microcapsule with polymer shell, which can be fabricated just blowing vapor of commonly-used instant adhesive (Cyanoacrylate monomer) into water as microbubbles. Therefore, the cyanoacrylate vapor contained inside microbubble initiates polymerization on the gasliquid interface soon after microbubbles are generated in water. Consequently, hollow microspheres coated by cyanoacrylate thin film are generated. In this report, we revealed that diameter distributions of microbubbles and microcapsules were approximately same and most of them were less than 10 μm, that is, smaller than blood capillary. In addition, we also revealed that hollow microcapsules enhanced the acoustic signal especially in the harmonic contrast imaging and were broken or agglomerated under the ultrasound field. As for the yield of hollow microcapsules, we revealed that sodium dodecyl sulfate addition to water phase instead of deoxycolic acid made the fabrication yield increased.

Effects of red blood cell aggregates dissociation on the estimation of ultrasound speckle image velocimetry.

PubMed

Yeom, Eunseop; Nam, Kweon-Ho; Paeng, Dong-Guk; Lee, Sang-Joon

2014-08-01

Ultrasound speckle image of blood is mainly attributed by red blood cells (RBCs) which tend to form RBC aggregates. RBC aggregates are separated into individual cells when the shear force is over a certain value. The dissociation of RBC aggregates has an influence on the performance of ultrasound speckle image velocimetry (SIV) technique in which a cross-correlation algorithm is applied to the speckle images to get the velocity field information. The present study aims to investigate the effect of the dissociation of RBC aggregates on the estimation quality of SIV technique. Ultrasound B-mode images were captured from the porcine blood circulating in a mock-up flow loop with varying flow rate. To verify the measurement performance of SIV technique, the centerline velocity measured by the SIV technique was compared with that measured by Doppler spectrograms. The dissociation of RBC aggregates was estimated by using decorrelation of speckle patterns in which the subsequent window was shifted as much as the speckle displacement to compensate decorrelation caused by in-plane loss of speckle patterns. The decorrelation of speckles is considerably increased according to shear rate. Its variations are different along the radial direction. Because the dissociation of RBC aggregates changes ultrasound speckles, the estimation quality of SIV technique is significantly correlated with the decorrelation of speckles. This degradation of measurement quality may be improved by increasing the data acquisition rate. This study would be useful for simultaneous measurement of hemodynamic and hemorheological information of blood flows using only speckle images. Copyright © 2014 Elsevier B.V. All rights reserved.

Calibration and Evaluation of Ultrasound Thermography using Infrared Imaging

PubMed Central

Hsiao, Yi-Sing; Deng, Cheri X.

2015-01-01

Real-time monitoring of the spatiotemporal evolution of tissue temperature is important to ensure safe and effective treatment in thermal therapies including hyperthermia and thermal ablation. Ultrasound thermography has been proposed as a non-invasive technique for temperature measurement, and accurate calibration of the temperature-dependent ultrasound signal changes against temperature is required. Here we report a method that uses infrared (IR) thermography for calibration and validation of ultrasound thermography. Using phantoms and cardiac tissue specimens subjected to high-intensity focused ultrasound (HIFU) heating, we simultaneously acquired ultrasound and IR imaging data from the same surface plane of a sample. The commonly used echo time shift-based method was chosen to compute ultrasound thermometry. We first correlated the ultrasound echo time shifts with IR-measured temperatures for material-dependent calibration and found that the calibration coefficient was positive for fat-mimicking phantom (1.49 ± 0.27) but negative for tissue-mimicking phantom (− 0.59 ± 0.08) and cardiac tissue (− 0.69 ± 0.18 °C-mm/ns). We then obtained the estimation error of the ultrasound thermometry by comparing against the IR measured temperature and revealed that the error increased with decreased size of the heated region. Consistent with previous findings, the echo time shifts were no longer linearly dependent on temperature beyond 45 – 50 °C in cardiac tissues. Unlike previous studies where thermocouples or water-bath techniques were used to evaluate the performance of ultrasound thermography, our results show that high resolution IR thermography provides a useful tool that can be applied to evaluate and understand the limitations of ultrasound thermography methods. PMID:26547634

Integration of Medical Imaging Including Ultrasound into a New Clinical Anatomy Curriculum

ERIC Educational Resources Information Center

Moscova, Michelle; Bryce, Deborah A.; Sindhusake, Doungkamol; Young, Noel

2015-01-01

In 2008 a new clinical anatomy curriculum with integrated medical imaging component was introduced into the University of Sydney Medical Program. Medical imaging used for teaching the new curriculum included normal radiography, MRI, CT scans, and ultrasound imaging. These techniques were incorporated into teaching over the first two years of the…

Development of the Fetal Vermis: New Biometry Reference Data and Comparison of 3 Diagnostic Modalities-3D Ultrasound, 2D Ultrasound, and MR Imaging.

PubMed

Katorza, E; Bertucci, E; Perlman, S; Taschini, S; Ber, R; Gilboa, Y; Mazza, V; Achiron, R

2016-07-01

Normal biometry of the fetal posterior fossa rules out most major anomalies of the cerebellum and vermis. Our aim was to provide new reference data of the fetal vermis in 4 biometric parameters by using 3 imaging modalities, 2D ultrasound, 3D ultrasound, and MR imaging, and to assess the relation among these modalities. A retrospective study was conducted between June 2011 and June 2013. Three different imaging modalities were used to measure vermis biometry: 2D ultrasound, 3D ultrasound, and MR imaging. The vermian parameters evaluated were the maximum superoinferior diameter, maximum anteroposterior diameter, the perimeter, and the surface area. Statistical analysis was performed to calculate centiles for gestational age and to assess the agreement among the 3 imaging modalities. The number of fetuses in the study group was 193, 172, and 151 for 2D ultrasound, 3D ultrasound, and MR imaging, respectively. The mean and median gestational ages were 29.1 weeks, 29.5 weeks (range, 21-35 weeks); 28.2 weeks, 29.05 weeks (range, 21-35 weeks); and 32.1 weeks, 32.6 weeks (range, 27-35 weeks) for 2D ultrasound, 3D ultrasound, and MR imaging, respectively. In all 3 modalities, the biometric measurements of the vermis have shown a linear growth with gestational age. For all 4 biometric parameters, the lowest results were those measured by MR imaging, while the highest results were measured by 3D ultrasound. The inter- and intraobserver agreement was excellent for all measures and all imaging modalities. Limits of agreement were considered acceptable for clinical purposes for all parameters, with excellent or substantial agreement defined by the intraclass correlation coefficient. Imaging technique-specific reference data should be used for the assessment of the fetal vermis in pregnancy. © 2016 by American Journal of Neuroradiology.

Contrast imaging in mouse embryos using high-frequency ultrasound.

PubMed

Denbeigh, Janet M; Nixon, Brian A; Puri, Mira C; Foster, F Stuart

2015-03-04

Ultrasound contrast-enhanced imaging can convey essential quantitative information regarding tissue vascularity and perfusion and, in targeted applications, facilitate the detection and measure of vascular biomarkers at the molecular level. Within the mouse embryo, this noninvasive technique may be used to uncover basic mechanisms underlying vascular development in the early mouse circulatory system and in genetic models of cardiovascular disease. The mouse embryo also presents as an excellent model for studying the adhesion of microbubbles to angiogenic targets (including vascular endothelial growth factor receptor 2 (VEGFR2) or αvβ3) and for assessing the quantitative nature of molecular ultrasound. We therefore developed a method to introduce ultrasound contrast agents into the vasculature of living, isolated embryos. This allows freedom in terms of injection control and positioning, reproducibility of the imaging plane without obstruction and motion, and simplified image analysis and quantification. Late gestational stage (embryonic day (E)16.6 and E17.5) murine embryos were isolated from the uterus, gently exteriorized from the yolk sac and microbubble contrast agents were injected into veins accessible on the chorionic surface of the placental disc. Nonlinear contrast ultrasound imaging was then employed to collect a number of basic perfusion parameters (peak enhancement, wash-in rate and time to peak) and quantify targeted microbubble binding in an endoglin mouse model. We show the successful circulation of microbubbles within living embryos and the utility of this approach in characterizing embryonic vasculature and microbubble behavior.

Fetal intracranial hemorrhage. Imaging by ultrasound and magnetic resonance imaging.

PubMed

Kirkinen, P; Partanen, K; Ryynänen, M; Ordén, M R

1997-08-01

To describe the magnetic resonance imaging (MRI) findings associated with fetal intracranial hemorrhage and to compare them with ultrasound findings. In four pregnancies complicated by fetal intracranial hemorrhage, fetal imaging was carried out using T2-weighted fast spin echo sequences and T1-weighted fast low angle shot imaging sequences and by transabdominal ultrasonography. An antepartum diagnosis of hemorrhage was made by ultrasound in one case and by MRI in two. Retrospectively, the hemorrhagic area could be identified from the MRI images in an additional two cases and from the ultrasound images in one case. In the cases of intraventricular hemorrhage, the MRI signal intensity in the T1-weighted images was increased in the hemorrhagic area as compared to the contralateral ventricle and brain parenchyma. In a case with subdural hemorrhage, T2-weighted MRI signals from the hemorrhagic area changed from low-to high-intensity signals during four weeks of follow-up. Better imaging of the intracranial anatomy was possible by MRI than by transabdominal ultrasonography. MRI can be used for imaging and dating fetal intracranial hemorrhages. Variable ultrasound and MRI findings are associated with this complication, depending on the age and location of the hemorrhage.

Localized Harmonic Motion Imaging for Focused Ultrasound Surgery Targeting

PubMed Central

Curiel, Laura; Hynynen, Kullervo

2011-01-01

Recently, an in vivo real-time ultrasound-based monitoring technique that uses localized harmonic motion (LHM) to detect changes in tissues during focused ultrasound surgery (FUS) has been proposed to control the exposure. This technique can potentially be used as well for targeting imaging. In the present study we evaluated the potential of using LHM to detect changes in stiffness and the feasibility of using it for imaging purposes in phantoms and in vivo tumor detection. A single-element FUS transducer (80 mm focal length, 100 mm diameter, 1.485 MHz) was used for inducing a localized harmonic motion and a separate ultrasound diagnostic transducer excited by a pulser/receiver (5 kHz PRF, 5 MHz) was used to track motion. The motion was estimated using cross-correlation techniques on the acquired RF signal. Silicon phantom studies were performed in order to determine the size of inclusion that was possible to detect using this technique. Inclusions were discerned from the surroundings as a reduction on LHM amplitude and it was possible to depict inclusions as small as 4 mm. The amplitude of the induced LHM was always lower at the inclusions as compared with the one obtained at the surroundings. Ten New Zealand rabbits had VX2 tumors implanted on their thighs and LHM was induced and measured at the tumor region. Tumors (as small as 10 mm in length and 4 mm in width) were discerned from the surroundings as a reduction on LHM amplitude. PMID:21683514

Computer model for harmonic ultrasound imaging.

PubMed

Li, Y; Zagzebski, J A

2000-01-01

Harmonic ultrasound imaging has received great attention from ultrasound scanner manufacturers and researchers. In this paper, we present a computer model that can generate realistic harmonic images. In this model, the incident ultrasound is modeled after the "KZK" equation, and the echo signal is modeled using linear propagation theory because the echo signal is much weaker than the incident pulse. Both time domain and frequency domain numerical solutions to the "KZK" equation were studied. Realistic harmonic images of spherical lesion phantoms were generated for scans by a circular transducer. This model can be a very useful tool for studying the harmonic buildup and dissipation processes in a nonlinear medium, and it can be used to investigate a wide variety of topics related to B-mode harmonic imaging.

Computer model for harmonic ultrasound imaging.

PubMed

Li, Y; Zagzebski, J A

2000-01-01

Harmonic ultrasound imaging has received great attention from ultrasound scanner manufacturers and researchers. Here, the authors present a computer model that can generate realistic harmonic images. In this model, the incident ultrasound is modeled after the "KZK" equation, and the echo signal is modeled using linear propagation theory because the echo signal is much weaker than the incident pulse. Both time domain and frequency domain numerical solutions to the "KZK" equation were studied. Realistic harmonic images of spherical lesion phantoms were generated for scans by a circular transducer. This model can be a very useful tool for studying the harmonic buildup and dissipation processes in a nonlinear medium, and it can be used to investigate a wide variety of topics related to B-mode harmonic imaging.

Texture Feature Analysis for Different Resolution Level of Kidney Ultrasound Images

NASA Astrophysics Data System (ADS)

Kairuddin, Wan Nur Hafsha Wan; Mahmud, Wan Mahani Hafizah Wan

2017-08-01

Image feature extraction is a technique to identify the characteristic of the image. The objective of this work is to discover the texture features that best describe a tissue characteristic of a healthy kidney from ultrasound (US) image. Three ultrasound machines that have different specifications are used in order to get a different quality (different resolution) of the image. Initially, the acquired images are pre-processed to de-noise the speckle to ensure the image preserve the pixels in a region of interest (ROI) for further extraction. Gaussian Low- pass Filter is chosen as the filtering method in this work. 150 of enhanced images then are segmented by creating a foreground and background of image where the mask is created to eliminate some unwanted intensity values. Statistical based texture features method is used namely Intensity Histogram (IH), Gray-Level Co-Occurance Matrix (GLCM) and Gray-level run-length matrix (GLRLM).This method is depends on the spatial distribution of intensity values or gray levels in the kidney region. By using One-Way ANOVA in SPSS, the result indicated that three features (Contrast, Difference Variance and Inverse Difference Moment Normalized) from GLCM are not statistically significant; this concludes that these three features describe a healthy kidney characteristics regardless of the ultrasound image quality.

Deterministic compressive sampling for high-quality image reconstruction of ultrasound tomography.

PubMed

Huy, Tran Quang; Tue, Huynh Huu; Long, Ton That; Duc-Tan, Tran

2017-05-25

A well-known diagnostic imaging modality, termed ultrasound tomography, was quickly developed for the detection of very small tumors whose sizes are smaller than the wavelength of the incident pressure wave without ionizing radiation, compared to the current gold-standard X-ray mammography. Based on inverse scattering technique, ultrasound tomography uses some material properties such as sound contrast or attenuation to detect small targets. The Distorted Born Iterative Method (DBIM) based on first-order Born approximation is an efficient diffraction tomography approach. One of the challenges for a high quality reconstruction is to obtain many measurements from the number of transmitters and receivers. Given the fact that biomedical images are often sparse, the compressed sensing (CS) technique could be therefore effectively applied to ultrasound tomography by reducing the number of transmitters and receivers, while maintaining a high quality of image reconstruction. There are currently several work on CS that dispose randomly distributed locations for the measurement system. However, this random configuration is relatively difficult to implement in practice. Instead of it, we should adopt a methodology that helps determine the locations of measurement devices in a deterministic way. For this, we develop the novel DCS-DBIM algorithm that is highly applicable in practice. Inspired of the exploitation of the deterministic compressed sensing technique (DCS) introduced by the authors few years ago with the image reconstruction process implemented using l 1 regularization. Simulation results of the proposed approach have demonstrated its high performance, with the normalized error approximately 90% reduced, compared to the conventional approach, this new approach can save half of number of measurements and only uses two iterations. Universal image quality index is also evaluated in order to prove the efficiency of the proposed approach. Numerical simulation results

Focused ultrasound thermal therapy system with ultrasound image guidance and temperature measurement feedback.

PubMed

Lin, Kao-Han; Young, Sun-Yi; Hsu, Ming-Chuan; Chan, Hsu; Chen, Yung-Yaw; Lin, Win-Li

2008-01-01

In this study, we developed a focused ultrasound (FUS) thermal therapy system with ultrasound image guidance and thermocouple temperature measurement feedback. Hydraulic position devices and computer-controlled servo motors were used to move the FUS transducer to the desired location with the measurement of actual movement by linear scale. The entire system integrated automatic position devices, FUS transducer, power amplifier, ultrasound image system, and thermocouple temperature measurement into a graphical user interface. For the treatment procedure, a thermocouple was implanted into a targeted treatment region in a tissue-mimicking phantom under ultrasound image guidance, and then the acoustic interference pattern formed by image ultrasound beam and low-power FUS beam was employed as image guidance to move the FUS transducer to have its focal zone coincident with the thermocouple tip. The thermocouple temperature rise was used to determine the sonication duration for a suitable thermal lesion as a high power was turned on and ultrasound image was used to capture the thermal lesion formation. For a multiple lesion formation, the FUS transducer was moved under the acoustic interference guidance to a new location and then it sonicated with the same power level and duration. This system was evaluated and the results showed that it could perform two-dimensional motion control to do a two-dimensional thermal therapy with a small localization error 0.5 mm. Through the user interface, the FUS transducer could be moved to heat the target region with the guidance of ultrasound image and acoustic interference pattern. The preliminary phantom experimental results demonstrated that the system could achieve the desired treatment plan satisfactorily.

ImSyn: photonic image synthesis applied to synthetic aperture radar, microscopy, and ultrasound imaging

NASA Astrophysics Data System (ADS)

Turpin, Terry M.; Lafuse, James L.

1993-02-01

ImSynTM is an image synthesis technology, developed and patented by Essex Corporation. ImSynTM can provide compact, low cost, and low power solutions to some of the most difficult image synthesis problems existing today. The inherent simplicity of ImSynTM enables the manufacture of low cost and reliable photonic systems for imaging applications ranging from airborne reconnaissance to doctor's office ultrasound. The initial application of ImSynTM technology has been to SAR processing; however, it has a wide range of applications such as: image correlation, image compression, acoustic imaging, x-ray tomographic (CAT, PET, SPECT), magnetic resonance imaging (MRI), microscopy, range- doppler mapping (extended TDOA/FDOA). This paper describes ImSynTM in terms of synthetic aperture microscopy and then shows how the technology can be extended to ultrasound and synthetic aperture radar. The synthetic aperture microscope (SAM) enables high resolution three dimensional microscopy with greater dynamic range than real aperture microscopes. SAM produces complex image data, enabling the use of coherent image processing techniques. Most importantly SAM produces the image data in a form that is easily manipulated by a digital image processing workstation.

Nonlinear ultrasound imaging of nanoscale acoustic biomolecules

NASA Astrophysics Data System (ADS)

Maresca, David; Lakshmanan, Anupama; Lee-Gosselin, Audrey; Melis, Johan M.; Ni, Yu-Li; Bourdeau, Raymond W.; Kochmann, Dennis M.; Shapiro, Mikhail G.

2017-02-01

Ultrasound imaging is widely used to probe the mechanical structure of tissues and visualize blood flow. However, the ability of ultrasound to observe specific molecular and cellular signals is limited. Recently, a unique class of gas-filled protein nanostructures called gas vesicles (GVs) was introduced as nanoscale (˜250 nm) contrast agents for ultrasound, accompanied by the possibilities of genetic engineering, imaging of targets outside the vasculature and monitoring of cellular signals such as gene expression. These possibilities would be aided by methods to discriminate GV-generated ultrasound signals from anatomical background. Here, we show that the nonlinear response of engineered GVs to acoustic pressure enables selective imaging of these nanostructures using a tailored amplitude modulation strategy. Finite element modeling predicted a strongly nonlinear mechanical deformation and acoustic response to ultrasound in engineered GVs. This response was confirmed with ultrasound measurements in the range of 10 to 25 MHz. An amplitude modulation pulse sequence based on this nonlinear response allows engineered GVs to be distinguished from linear scatterers and other GV types with a contrast ratio greater than 11.5 dB. We demonstrate the effectiveness of this nonlinear imaging strategy in vitro, in cellulo, and in vivo.

High-resolution vascular tissue characterization in mice using 55MHz ultrasound hybrid imaging.

PubMed

Mahmoud, Ahmed M; Sandoval, Cesar; Teng, Bunyen; Schnermann, Jurgen B; Martin, Karen H; Mustafa, S Jamal; Mukdadi, Osama M

2013-03-01

Ultrasound and Duplex ultrasonography in particular are routinely used to diagnose cardiovascular disease (CVD), which is the leading cause of morbidity and mortality worldwide. However, these techniques may not be able to characterize vascular tissue compositional changes due to CVD. This work describes an ultrasound-based hybrid imaging technique that can be used for vascular tissue characterization and the diagnosis of atherosclerosis. Ultrasound radiofrequency (RF) data were acquired and processed in time, frequency, and wavelet domains to extract six parameters including time integrated backscatter (T(IB)), time variance (T(var)), time entropy (T(E)), frequency integrated backscatter (F(IB)), wavelet root mean square value (W(rms)), and wavelet integrated backscatter (W(IB)). Each parameter was used to reconstruct an image co-registered to morphological B-scan. The combined set of hybrid images were used to characterize vascular tissue in vitro and in vivo using three mouse models including control (C57BL/6), and atherosclerotic apolipoprotein E-knockout (APOE-KO) and APOE/A(1) adenosine receptor double knockout (DKO) mice. The technique was tested using high-frequency ultrasound including single-element (center frequency=55 MHz) and commercial array (center frequency=40 MHz) systems providing superior spatial resolutions of 24 μm and 40 μm, respectively. Atherosclerotic vascular lesions in the APOE-KO mouse exhibited the highest values (contrast) of -10.11±1.92 dB, -12.13±2.13 dB, -7.54±1.45 dB, -5.10±1.06 dB, -5.25±0.94 dB, and -10.23±2.12 dB in T(IB), T(var), T(E), F(IB), W(rms), W(IB) hybrid images (n=10, p<0.05), respectively. Control segments of normal vascular tissue showed the lowest values of -20.20±2.71 dB, -22.54±4.54 dB, -14.94±2.05 dB, -9.64±1.34 dB, -10.20±1.27 dB, and -19.36±3.24 dB in same hybrid images (n=6, p<0.05). Results from both histology and optical images showed good agreement with ultrasound findings within a maximum

High-resolution vascular tissue characterization in mice using 55 MHz ultrasound hybrid imaging

PubMed Central

Mahmoud, Ahmed M.; Sandoval, Cesar; Teng, Bunyen; Schnermann, Jurgen B.; Martin, Karen H.; Mustafa, S. Jamal; Mukdadi, Osama M.

2012-01-01

Ultrasound and Duplex ultrasonography in particular are routinely used to diagnose cardiovascular disease (CVD), which is the leading cause of morbidity and mortality worldwide. However, these techniques may not be able to characterize vascular tissue compositional changes due to CVD. This work describes an ultrasound-based hybrid imaging technique that can be used for vascular tissue characterization and the diagnosis of atherosclerosis. Ultrasound radiofrequency (RF) data were acquired and processed in time, frequency, and wavelet domains to extract six parameters including time integrated backscatter (TIB), time variance (Tvar), time entropy (TE), frequency integrated backscatter (FIB), wavelet root mean square value (Wrms), and wavelet integrated backscatter (WIB). Each parameter was used to reconstruct an image co-registered to morphological B-scan. The combined set of hybrid images were used to characterize vascular tissue in vitro and in vivo using three mouse models including control (C57BL/6), and atherosclerotic apolipoprotein E-knockout (APOE-KO) and APOE/A1 adenosine receptor double knockout (DKO) mice. The technique was tested using high-frequency ultrasound including single-element (center frequency = 55 MHz) and commercial array (center frequency = 40 MHz) systems providing superior spatial resolutions of 24 μm and 40 μm, respectively. Atherosclerotic vascular lesions in the APOE-KO mouse exhibited the highest values (contrast) of −10.11 ± 1.92 dB, −12.13 ± 2.13 dB, −7.54 ± 1.45 dB, −5.10 ± 1.06 dB, −5.25 ± 0.94 dB, and −10.23 ± 2.12 dB in TIB, Tvar, TE, FIB, Wrms, WIB hybrid images (n = 10, p < 0.05), respectively. Control segments of normal vascular tissue showed the lowest values of −20.20 ± 2.71 dB, −22.54 ± 4.54 dB, −14.94 ± 2.05 dB, −9.64 ± 1.34 dB, −10.20 ± 1.27 dB, and −19.36 ± 3.24 dB in same hybrid images (n = 6, p < 0.05). Results from both histology and optical images showed good agreement with

Method and system to synchronize acoustic therapy with ultrasound imaging

NASA Technical Reports Server (NTRS)

Hossack, James (Inventor); Owen, Neil (Inventor); Bailey, Michael R. (Inventor)

2009-01-01

Interference in ultrasound imaging when used in connection with high intensity focused ultrasound (HIFU) is avoided by employing a synchronization signal to control the HIFU signal. Unless the timing of the HIFU transducer is controlled, its output will substantially overwhelm the signal produced by ultrasound imaging system and obscure the image it produces. The synchronization signal employed to control the HIFU transducer is obtained without requiring modification of the ultrasound imaging system. Signals corresponding to scattered ultrasound imaging waves are collected using either the HIFU transducer or a dedicated receiver. A synchronization processor manipulates the scattered ultrasound imaging signals to achieve the synchronization signal, which is then used to control the HIFU bursts so as to substantially reduce or eliminate HIFU interference in the ultrasound image. The synchronization processor can alternatively be implemented using a computing device or an application-specific circuit.

A Dual-Modality System for Both Multi-Color Ultrasound-Switchable Fluorescence and Ultrasound Imaging

PubMed Central

Kandukuri, Jayanth; Yu, Shuai; Cheng, Bingbing; Bandi, Venugopal; D’Souza, Francis; Nguyen, Kytai T.; Hong, Yi; Yuan, Baohong

2017-01-01

Simultaneous imaging of multiple targets (SIMT) in opaque biological tissues is an important goal for molecular imaging in the future. Multi-color fluorescence imaging in deep tissues is a promising technology to reach this goal. In this work, we developed a dual-modality imaging system by combining our recently developed ultrasound-switchable fluorescence (USF) imaging technology with the conventional ultrasound (US) B-mode imaging. This dual-modality system can simultaneously image tissue acoustic structure information and multi-color fluorophores in centimeter-deep tissue with comparable spatial resolutions. To conduct USF imaging on the same plane (i.e., x-z plane) as US imaging, we adopted two 90°-crossed ultrasound transducers with an overlapped focal region, while the US transducer (the third one) was positioned at the center of these two USF transducers. Thus, the axial resolution of USF is close to the lateral resolution, which allows a point-by-point USF scanning on the same plane as the US imaging. Both multi-color USF and ultrasound imaging of a tissue phantom were demonstrated. PMID:28165390

Multi-Frequency Intravascular Ultrasound (IVUS) Imaging

PubMed Central

Ma, Teng; Yu, Mingyue; Chen, Zeyu; Fei, Chunlong; Shung, K. Kirk; Zhou, Qifa

2015-01-01

Acute coronary syndrome (ACS) is frequently associated with the sudden rupture of a vulnerable atherosclerotic plaque within the coronary artery. Several unique physiological features, including a thin fibrous cap accompanied by a necrotic lipid core, are the targeted indicators for identifying the vulnerable plaques. Intravascular ultrasound (IVUS), a catheter-based imaging technology, has been routinely performed in clinics for more than 20 years to describe the morphology of the coronary artery and guide percutaneous coronary interventions. However, conventional IVUS cannot facilitate the risk assessment of ACS because of its intrinsic limitations, such as insufficient resolution. Renovation of the IVUS technology is essentially needed to overcome the limitations and enhance the coronary artery characterization. In this paper, a multi-frequency intravascular ultrasound (IVUS) imaging system was developed by incorporating a higher frequency IVUS transducer (80 to 150 MHz) with the conventional IVUS (30–50 MHz) system. The newly developed system maintains the advantage of deeply penetrating imaging with the conventional IVUS, while offering an improved higher resolution image with IVUS at a higher frequency. The prototyped multi-frequency catheter has a clinically compatible size of 0.95 mm and a favorable capability of automated image co-registration. In vitro human coronary artery imaging has demonstrated the feasibility and superiority of the multi-frequency IVUS imaging system to deliver a more comprehensive visualization of the coronary artery. This ultrasonic-only intravascular imaging technique, based on a moderate refinement of the conventional IVUS system, is not only cost-effective from the perspective of manufacturing and clinical practice, but also holds the promise of future translation into clinical benefits. PMID:25585394

Nonlocal Total-Variation-Based Speckle Filtering for Ultrasound Images.

PubMed

Wen, Tiexiang; Gu, Jia; Li, Ling; Qin, Wenjian; Wang, Lei; Xie, Yaoqin

2016-07-01

Ultrasound is one of the most important medical imaging modalities for its real-time and portable imaging advantages. However, the contrast resolution and important details are degraded by the speckle in ultrasound images. Many speckle filtering methods have been developed, but they are suffered from several limitations, difficult to reach a balance between speckle reduction and edge preservation. In this paper, an adaptation of the nonlocal total variation (NLTV) filter is proposed for speckle reduction in ultrasound images. The speckle is modeled via a signal-dependent noise distribution for the log-compressed ultrasound images. Instead of the Euclidian distance, the statistical Pearson distance is introduced in this study for the similarity calculation between image patches via the Bayesian framework. And the Split-Bregman fast algorithm is used to solve the adapted NLTV despeckling functional. Experimental results on synthetic and clinical ultrasound images and comparisons with some classical and recent algorithms are used to demonstrate its improvements in both speckle noise reduction and tissue boundary preservation for ultrasound images. © The Author(s) 2015.

Material characterization and defect inspection in ultrasound images

NASA Astrophysics Data System (ADS)

Zmola, Carl; Segal, Andrew C.; Lovewell, Brian; Mahdavieh, Jacob; Ross, Joseph; Nash, Charles

1992-08-01

The use of ultrasonic imaging to analyze defects and characterize materials is critical in the development of non-destructive testing and non-destructive evaluation (NDT/NDE) tools for manufacturing. To develop better quality control and reliability in the manufacturing environment advanced image processing techniques are useful. For example, through the use of texture filtering on ultrasound images, we have been able to filter characteristic textures from highly textured C-scan images of materials. The materials have highly regular characteristic textures which are of the same resolution and dynamic range as other important features within the image. By applying texture filters and adaptively modifying their filter response, we have examined a family of filters for removing these textures.

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

NASA Astrophysics Data System (ADS)

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.

A hybrid algorithm for speckle noise reduction of ultrasound images.

PubMed

Singh, Karamjeet; Ranade, Sukhjeet Kaur; Singh, Chandan

2017-09-01

Medical images are contaminated by multiplicative speckle noise which significantly reduce the contrast of ultrasound images and creates a negative effect on various image interpretation tasks. In this paper, we proposed a hybrid denoising approach which collaborate the both local and nonlocal information in an efficient manner. The proposed hybrid algorithm consist of three stages in which at first stage the use of local statistics in the form of guided filter is used to reduce the effect of speckle noise initially. Then, an improved speckle reducing bilateral filter (SRBF) is developed to further reduce the speckle noise from the medical images. Finally, to reconstruct the diffused edges we have used the efficient post-processing technique which jointly considered the advantages of both bilateral and nonlocal mean (NLM) filter for the attenuation of speckle noise efficiently. The performance of proposed hybrid algorithm is evaluated on synthetic, simulated and real ultrasound images. The experiments conducted on various test images demonstrate that our proposed hybrid approach outperforms the various traditional speckle reduction approaches included recently proposed NLM and optimized Bayesian-based NLM. The results of various quantitative, qualitative measures and by visual inspection of denoise synthetic and real ultrasound images demonstrate that the proposed hybrid algorithm have strong denoising capability and able to preserve the fine image details such as edge of a lesion better than previously developed methods for speckle noise reduction. The denoising and edge preserving capability of hybrid algorithm is far better than existing traditional and recently proposed speckle reduction (SR) filters. The success of proposed algorithm would help in building the lay foundation for inventing the hybrid algorithms for denoising of ultrasound images. Copyright © 2017 Elsevier B.V. All rights reserved.

WE-AB-206-01: Diagnostic Ultrasound Imaging Quality Assurance

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

Zagzebski, J.

The involvement of medical physicists in diagnostic ultrasound imaging service is increasing due to QC and accreditation requirements. The goal of this ultrasound hands-on workshop is to demonstrate quality control (QC) testing in diagnostic ultrasound and to provide updates in ACR ultrasound accreditation requirements. The first half of this workshop will include two presentations reviewing diagnostic ultrasound QA/QC and ACR ultrasound accreditation requirements. The second half of the workshop will include live demonstrations of basic QC tests. An array of ultrasound testing phantoms and ultrasound scanners will be available for attendees to learn diagnostic ultrasound QC in a hands-on environmentmore » with live demonstrations and on-site instructors. The targeted attendees are medical physicists in diagnostic imaging. Learning Objectives: Gain familiarity with common elements of a QA/QC program for diagnostic ultrasound imaging dentify QC tools available for testing diagnostic ultrasound systems and learn how to use these tools Learn ACR ultrasound accreditation requirements Jennifer Walter is an employee of American College of Radiology on Ultrasound Accreditation.« less

Carotid Ultrasound Imaging

MedlinePlus

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

Noninvasive detection of intimal xanthoma using combined ultrasound, strain rate and photoacoustic imaging.

PubMed

Graf, Iulia M; Kim, Seungsoo; Wang, Bo; Smalling, Richard; Emelianov, Stanislav

2012-03-01

The structure, composition and mechanics of carotid artery are good indicators of early progressive atherosclerotic lesions. The combination of three imaging modalities (ultrasound, strain rate and photoacoustic imaging) which could provide corroborative information about the named arterial properties could enhance the characterization of intimal xanthoma. The experiments were performed using a New Zealand white rabbit model of atherosclerosis. The aorta excised from an atherosclerotic rabbit was scanned ex vivo using the three imaging techniques: (1) ultrasound imaging of the longitudinal section: standard ultrasound B-mode (74Hz frame rate); (2) strain rate imaging: the artery was flushed with blood and a 1.5Hz physiologic pulsation was induced, while the ultrasound data were recorded at higher frame rate (296Hz); (3) photoacoustic imaging: the artery was irradiated with nanosecond pulsed laser light of low fluence in the 1210-1230nm wavelength range and the photoacoustic data was recorded at 10Hz frame rate. Post processing algorithms based on cross-correlation and optical absorption variation were implemented to derive strain rate and spectroscopic photoacoustic images, respectively. Based on the spatio-temporal variation in displacement of different regions within the arterial wall, strain rate imaging reveals differences in tissue mechanical properties. Additionally, spectroscopic photoacoustic imaging can spatially resolve the optical absorption properties of arterial tissue and identify the location of lipid pools. The study demonstrates that ultrasound, strain rate and photoacoustic imaging can be used to simultaneously evaluate the structure, the mechanics and the composition of atherosclerotic lesions to improve the assessment of plaque vulnerability. Copyright © 2011 Elsevier B.V. All rights reserved.

Integrated photoacoustic/ultrasound/HFU system based on a clinical ultrasound imaging platform

NASA Astrophysics Data System (ADS)

Kim, Jeesu; Choi, Wonseok; Park, Eun-Yeong; Kim, Chulhong

2018-02-01

Non-invasive treatment of tumor is beneficial for the favorable prognosis of the patients. High Intensity Focused Ultrasound (HIFU) is an emerging non-invasive treatment tool that ablates tumor lesions by increasing local temperature without damaging surrounding tissues. In HIFU therapy, accurate focusing of the HIFU energy into the target lesion and real-time assessment of thermal distribution are critical for successful and safe treatment. Photoacoustic (PA) imaging is a novel biomedical imaging technique that can visualize functional information of biological tissues based on optical absorption and thermoelastic expansion. One unique feature of PA imaging is that the amplitude of the PA signal reflects the local temperature. Here, we demonstrate a real-time temperature monitoring system that can evaluate thermal distribution during HIFU therapy. We have integrated a HIFU treatment system, a clinical ultrasound (US) machine, and a tunable laser system and have acquired real-time PA/US images of in vitro phantoms and in vivo animals during HIFU therapy without interference from the therapeutic US waves. We have also evaluated the temperature monitoring capability of the system by comparing the amplitude of PA signals with the measured temperature in melanoma tumor bearing mice. Although much more updates are required for clinical applications, the results show the promising potential of the system to ensure accurate and safe HIFU therapy by monitoring the thermal distribution of the treatment area.

Hybrid MRI-Ultrasound acquisitions, and scannerless real-time imaging.

PubMed

Preiswerk, Frank; Toews, Matthew; Cheng, Cheng-Chieh; Chiou, Jr-Yuan George; Mei, Chang-Sheng; Schaefer, Lena F; Hoge, W Scott; Schwartz, Benjamin M; Panych, Lawrence P; Madore, Bruno

2017-09-01

To combine MRI, ultrasound, and computer science methodologies toward generating MRI contrast at the high frame rates of ultrasound, inside and even outside the MRI bore. A small transducer, held onto the abdomen with an adhesive bandage, collected ultrasound signals during MRI. Based on these ultrasound signals and their correlations with MRI, a machine-learning algorithm created synthetic MR images at frame rates up to 100 per second. In one particular implementation, volunteers were taken out of the MRI bore with the ultrasound sensor still in place, and MR images were generated on the basis of ultrasound signal and learned correlations alone in a "scannerless" manner. Hybrid ultrasound-MRI data were acquired in eight separate imaging sessions. Locations of liver features, in synthetic images, were compared with those from acquired images: The mean error was 1.0 pixel (2.1 mm), with best case 0.4 and worst case 4.1 pixels (in the presence of heavy coughing). For results from outside the bore, qualitative validation involved optically tracked ultrasound imaging with/without coughing. The proposed setup can generate an accurate stream of high-speed MR images, up to 100 frames per second, inside or even outside the MR bore. Magn Reson Med 78:897-908, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Application of imaging and ultrasound to the quality grading of beef

NASA Astrophysics Data System (ADS)

Anselmo, V. J.; Gammell, P. M.

1980-04-01

The results of a study conducted to assist the Department of Agriculture in the task of considering innovative methods for the grading of carcass beef for human consumption is presented. The processing of photographic, television and ultrasound images of the longissimus dorsi muscle at the 12/13th rib cut was undertaken. The results showed that a correlation could be developed between the quality grade of the carcass as determined by a professional grader, and the fat to area ratio of the muscle as determined by image processing techniques. In addition, the use of ultrasound shows the potential for grading of an unsliced carcass or a live animal.

Application of imaging and ultrasound to the quality grading of beef

NASA Technical Reports Server (NTRS)

Anselmo, V. J.; Gammell, P. M.

1980-01-01

The results of a study conducted to assist the Department of Agriculture in the task of considering innovative methods for the grading of carcass beef for human consumption is presented. The processing of photographic, television and ultrasound images of the longissimus dorsi muscle at the 12/13th rib cut was undertaken. The results showed that a correlation could be developed between the quality grade of the carcass as determined by a professional grader, and the fat to area ratio of the muscle as determined by image processing techniques. In addition, the use of ultrasound shows the potential for grading of an unsliced carcass or a live animal.

Musculoskeletal ultrasound and other imaging modalities in rheumatoid arthritis.

PubMed

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

2013-05-01

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

Thermal Field Imaging Using Ultrasound

NASA Technical Reports Server (NTRS)

Andereck, D.; Rahal, S.; Fife, S.

2000-01-01

is then possible to find the average temperature at different locations along the chamber, thereby determining the temperature profile along the system. (In the future we will construct an array of transducers. This will give us the capability to determine the temperature profile much more rapidly than at present, an important consideration if time-dependent phenomena are to be studied.) To validate our procedure we introduced encapsulated liquid crystal particles into glycerol. The liquid crystal particles' color varies depending on the temperature of the fluid. A photograph of the fluid through transparent sidewalls therefore gives a picture of the temperature field of the convecting fluid, independent of our ultrasound imaging. A representative result is shown in the Figure 1, which reveals a very satisfying correspondence between the two techniques. Therefore we have a great deal of confidence that the ultrasound imaging approach is indeed measuring the actual temperature profile of the fluid. The technique has also been applied to convecting liquid metal flows, and representative data will be presented from those experiments as well.

Beating heart mitral valve repair with integrated ultrasound imaging

NASA Astrophysics Data System (ADS)

McLeod, A. Jonathan; Moore, John T.; Peters, Terry M.

2015-03-01

Beating heart valve therapies rely extensively on image guidance to treat patients who would be considered inoperable with conventional surgery. Mitral valve repair techniques including the MitrClip, NeoChord, and emerging transcatheter mitral valve replacement techniques rely on transesophageal echocardiography for guidance. These images are often difficult to interpret as the tool will cause shadowing artifacts that occlude tissue near the target site. Here, we integrate ultrasound imaging directly into the NeoChord device. This provides an unobstructed imaging plane that can visualize the valve lea ets as they are engaged by the device and can aid in achieving both a proper bite and spacing between the neochordae implants. A proof of concept user study in a phantom environment is performed to provide a proof of concept for this device.

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

PubMed Central

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

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, 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. PMID:26658577

Molecular Ultrasound Imaging for the Detection of Neural Inflammation

NASA Astrophysics Data System (ADS)

Volz, Kevin R.

Molecular imaging is a form of nanotechnology that enables the noninvasive examination of biological processes in vivo. Radiopharmaceutical agents are used to selectively target biochemical markers, which permits their detection and evaluation. Early visualization of molecular variations indicative of pathophysiological processes can aid in patient diagnoses and management decisions. Molecular imaging is performed by introducing molecular probes into the body. Molecular probes are often contrast agents that have been nanoengineered to selectively target and tether to molecules, enabling their radiologic identification. Ultrasound contrast agents have been demonstrated as an effective method of detecting perfusion at the tissue level. Through a nanoengineering process, ultrasound contrast agents can be targeted to specific molecules, thereby extending ultrasound's capabilities from the tissue to molecular level. Molecular ultrasound, or targeted contrast enhanced ultrasound (TCEUS), has recently emerged as a popular molecular imaging technique due to its ability to provide real-time anatomical and functional information in the absence of ionizing radiation. However, molecular ultrasound represents a novel form of molecular imaging, and consequently remains largely preclinical. A review of the TCEUS literature revealed multiple preclinical studies demonstrating its success in detecting inflammation in a variety of tissues. Although, a gap was identified in the existing evidence, as TCEUS effectiveness for detection of neural inflammation in the spinal cord was unable to be uncovered. This gap in knowledge, coupled with the profound impacts that this TCEUS application could have clinically, provided rationale for its exploration, and use as contributory evidence for the molecular ultrasound body of literature. An animal model that underwent a contusive spinal cord injury was used to establish preclinical evidence of TCEUS to detect neural inflammation. Imaging was

Calibration and Evaluation of Ultrasound Thermography Using Infrared Imaging.

PubMed

Hsiao, Yi-Sing; Deng, Cheri X

2016-02-01

Real-time monitoring of the spatiotemporal evolution of tissue temperature is important to ensure safe and effective treatment in thermal therapies including hyperthermia and thermal ablation. Ultrasound thermography has been proposed as a non-invasive technique for temperature measurement, and accurate calibration of the temperature-dependent ultrasound signal changes against temperature is required. Here we report a method that uses infrared thermography for calibration and validation of ultrasound thermography. Using phantoms and cardiac tissue specimens subjected to high-intensity focused ultrasound heating, we simultaneously acquired ultrasound and infrared imaging data from the same surface plane of a sample. The commonly used echo time shift-based method was chosen to compute ultrasound thermometry. We first correlated the ultrasound echo time shifts with infrared-measured temperatures for material-dependent calibration and found that the calibration coefficient was positive for fat-mimicking phantom (1.49 ± 0.27) but negative for tissue-mimicking phantom (-0.59 ± 0.08) and cardiac tissue (-0.69 ± 0.18°C-mm/ns). We then obtained the estimation error of the ultrasound thermometry by comparing against the infrared-measured temperature and revealed that the error increased with decreased size of the heated region. Consistent with previous findings, the echo time shifts were no longer linearly dependent on temperature beyond 45°C-50°C in cardiac tissues. Unlike previous studies in which thermocouples or water bath techniques were used to evaluate the performance of ultrasound thermography, our results indicate that high-resolution infrared thermography is a useful tool that can be applied to evaluate and understand the limitations of ultrasound thermography methods. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

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

PubMed

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

2018-01-17

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

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

NASA Astrophysics Data System (ADS)

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

2018-01-01

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

Counter-propagating wave interaction for contrast-enhanced ultrasound imaging

NASA Astrophysics Data System (ADS)

Renaud, G.; Bosch, J. G.; ten Kate, G. L.; Shamdasani, V.; Entrekin, R.; de Jong, N.; van der Steen, A. F. W.

2012-11-01

Most techniques for contrast-enhanced ultrasound imaging require linear propagation to detect nonlinear scattering of contrast agent microbubbles. Waveform distortion due to nonlinear propagation impairs their ability to distinguish microbubbles from tissue. As a result, tissue can be misclassified as microbubbles, and contrast agent concentration can be overestimated; therefore, these artifacts can significantly impair the quality of medical diagnoses. Contrary to biological tissue, lipid-coated gas microbubbles used as a contrast agent allow the interaction of two acoustic waves propagating in opposite directions (counter-propagation). Based on that principle, we describe a strategy to detect microbubbles that is free from nonlinear propagation artifacts. In vitro images were acquired with an ultrasound scanner in a phantom of tissue-mimicking material with a cavity containing a contrast agent. Unlike the default mode of the scanner using amplitude modulation to detect microbubbles, the pulse sequence exploiting counter-propagating wave interaction creates no pseudoenhancement behind the cavity in the contrast image.

Sparse dictionary for synthetic transmit aperture medical ultrasound imaging.

PubMed

Wang, Ping; Jiang, Jin-Yang; Li, Na; Luo, Han-Wu; Li, Fang; Cui, Shi-Gang

2017-07-01

It is possible to recover a signal below the Nyquist sampling limit using a compressive sensing technique in ultrasound imaging. However, the reconstruction enabled by common sparse transform approaches does not achieve satisfactory results. Considering the ultrasound echo signal's features of attenuation, repetition, and superposition, a sparse dictionary with the emission pulse signal is proposed. Sparse coefficients in the proposed dictionary have high sparsity. Images reconstructed with this dictionary were compared with those obtained with the three other common transforms, namely, discrete Fourier transform, discrete cosine transform, and discrete wavelet transform. The performance of the proposed dictionary was analyzed via a simulation and experimental data. The mean absolute error (MAE) was used to quantify the quality of the reconstructions. Experimental results indicate that the MAE associated with the proposed dictionary was always the smallest, the reconstruction time required was the shortest, and the lateral resolution and contrast of the reconstructed images were also the closest to the original images. The proposed sparse dictionary performed better than the other three sparse transforms. With the same sampling rate, the proposed dictionary achieved excellent reconstruction quality.

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

NASA Astrophysics Data System (ADS)

Saad, Ashraf A.; Shapiro, Linda G.

2008-03-01

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

Quantitative volumetric imaging of normal, neoplastic and hyperplastic mouse prostate using ultrasound.

PubMed

Singh, Shalini; Pan, Chunliu; Wood, Ronald; Yeh, Chiuan-Ren; Yeh, Shuyuan; Sha, Kai; Krolewski, John J; Nastiuk, Kent L

2015-09-21

Genetically engineered mouse models are essential to the investigation of the molecular mechanisms underlying human prostate pathology and the effects of therapy on the diseased prostate. Serial in vivo volumetric imaging expands the scope and accuracy of experimental investigations of models of normal prostate physiology, benign prostatic hyperplasia and prostate cancer, which are otherwise limited by the anatomy of the mouse prostate. Moreover, accurate imaging of hyperplastic and tumorigenic prostates is now recognized as essential to rigorous pre-clinical trials of new therapies. Bioluminescent imaging has been widely used to determine prostate tumor size, but is semi-quantitative at best. Magnetic resonance imaging can determine prostate volume very accurately, but is expensive and has low throughput. We therefore sought to develop and implement a high throughput, low cost, and accurate serial imaging protocol for the mouse prostate. We developed a high frequency ultrasound imaging technique employing 3D reconstruction that allows rapid and precise assessment of mouse prostate volume. Wild-type mouse prostates were examined (n = 4) for reproducible baseline imaging, and treatment effects on volume were compared, and blinded data analyzed for intra- and inter-operator assessments of reproducibility by correlation and for Bland-Altman analysis. Examples of benign prostatic hyperplasia mouse model prostate (n = 2) and mouse prostate implantation of orthotopic human prostate cancer tumor and its growth (n =  ) are also demonstrated. Serial measurement volume of the mouse prostate revealed that high frequency ultrasound was very precise. Following endocrine manipulation, regression and regrowth of the prostate could be monitored with very low intra- and interobserver variability. This technique was also valuable to monitor the development of prostate growth in a model of benign prostatic hyperplasia. Additionally, we demonstrate accurate ultrasound image

Endoscopic ultrasound-guided techniques for diagnosing pancreatic mass lesions: Can we do better?

PubMed Central

Storm, Andrew C; Lee, Linda S

2016-01-01

The diagnostic approach to a possible pancreatic mass lesion relies first upon various non-invasive imaging modalities, including computed tomography, ultrasound, and magnetic resonance imaging techniques. Once a suspect lesion has been identified, tissue acquisition for characterization of the lesion is often paramount in developing an individualized therapeutic approach. Given the high prevalence and mortality associated with pancreatic cancer, an ideal approach to diagnosing pancreatic mass lesions would be safe, highly sensitive, and reproducible across various practice settings. Tools, in addition to radiologic imaging, currently employed in the initial evaluation of a patient with a pancreatic mass lesion include serum tumor markers, endoscopic retrograde cholangiopancreatography, and endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). EUS-FNA has grown to become the gold standard in tissue diagnosis of pancreatic lesions. PMID:27818584

Filtering and left ventricle segmentation of the fetal heart in ultrasound images

NASA Astrophysics Data System (ADS)

Vargas-Quintero, Lorena; Escalante-Ramírez, Boris

2013-11-01

In this paper, we propose to use filtering methods and a segmentation algorithm for the analysis of fetal heart in ultrasound images. Since noise speckle makes difficult the analysis of ultrasound images, the filtering process becomes a useful task in these types of applications. The filtering techniques consider in this work assume that the speckle noise is a random variable with a Rayleigh distribution. We use two multiresolution methods: one based on wavelet decomposition and the another based on the Hermite transform. The filtering process is used as way to strengthen the performance of the segmentation tasks. For the wavelet-based approach, a Bayesian estimator at subband level for pixel classification is employed. The Hermite method computes a mask to find those pixels that are corrupted by speckle. On the other hand, we picked out a method based on a deformable model or "snake" to evaluate the influence of the filtering techniques in the segmentation task of left ventricle in fetal echocardiographic images.

Probabilistic registration of an unbiased statistical shape model to ultrasound images of the spine

NASA Astrophysics Data System (ADS)

Rasoulian, Abtin; Rohling, Robert N.; Abolmaesumi, Purang

2012-02-01

The placement of an epidural needle is among the most difficult regional anesthetic techniques. Ultrasound has been proposed to improve success of placement. However, it has not become the standard-of-care because of limitations in the depictions and interpretation of the key anatomical features. We propose to augment the ultrasound images with a registered statistical shape model of the spine to aid interpretation. The model is created with a novel deformable group-wise registration method which utilizes a probabilistic approach to register groups of point sets. The method is compared to a volume-based model building technique and it demonstrates better generalization and compactness. We instantiate and register the shape model to a spine surface probability map extracted from the ultrasound images. Validation is performed on human subjects. The achieved registration accuracy (2-4 mm) is sufficient to guide the choice of puncture site and trajectory of an epidural needle.

Extracting cardiac myofiber orientations from high frequency ultrasound images

NASA Astrophysics Data System (ADS)

Qin, Xulei; Cong, Zhibin; Jiang, Rong; Shen, Ming; Wagner, Mary B.; Kirshbom, Paul; Fei, Baowei

2013-03-01

Cardiac myofiber plays an important role in stress mechanism during heart beating periods. The orientation of myofibers decides the effects of the stress distribution and the whole heart deformation. It is important to image and quantitatively extract these orientations for understanding the cardiac physiological and pathological mechanism and for diagnosis of chronic diseases. Ultrasound has been wildly used in cardiac diagnosis because of its ability of performing dynamic and noninvasive imaging and because of its low cost. An extraction method is proposed to automatically detect the cardiac myofiber orientations from high frequency ultrasound images. First, heart walls containing myofibers are imaged by B-mode high frequency (<20 MHz) ultrasound imaging. Second, myofiber orientations are extracted from ultrasound images using the proposed method that combines a nonlinear anisotropic diffusion filter, Canny edge detector, Hough transform, and K-means clustering. This method is validated by the results of ultrasound data from phantoms and pig hearts.

In-Plane Ultrasound-Guided Knee Injection Through a Lateral Suprapatellar Approach: A Safe Technique.

PubMed

Chagas-Neto, Francisco A; Taneja, Atul K; Gregio-Junior, Everaldo; Nogueira-Barbosa, Marcello H

2017-06-01

This study aims to describe a technique for in-plane ultrasound-guided knee arthrography through a lateral suprapatellar approach, reporting its accuracy and related complications. A retrospective search was performed for computed tomography and magnetic resonance reports from June 2013 through June 2015. Imaging studies, puncture descriptions, and guided-procedure images were reviewed along with clinical and surgical history. A fellowship-trained musculoskeletal radiologist performed all procedures under sterile technique and ultrasound guidance with the probe in oblique position on the lateral suprapatellar recess after local anesthesia with the patient on dorsal decubitus, hip in neutral rotation, and 30 to 45 degrees of knee flexion. A total of 86 consecutive subjects were evaluated (mean, 55 years). All subjects underwent intra-articular injection of contrast, which was successfully reached in the first attempt in 94.2% of the procedures (81/86), and in the second attempt in 5.8% (5/86) after needle repositioning without a second puncture. There were no postprocedural reports of regional complications at the puncture site, such as significant pain, bleeding, or vascular lesions. Our study demonstrates that in-plane ultrasound-guided injection of the knee in semiflexion approaching the lateral suprapatellar recess is a safe and useful technique to administer intra-articular contrast solution, as an alternative method without radiation exposure.

40 MHz high-frequency ultrafast ultrasound imaging.

PubMed

Huang, Chih-Chung; Chen, Pei-Yu; Peng, Po-Hsun; Lee, Po-Yang

2017-06-01

Ultrafast high-frame-rate ultrasound imaging based on coherent-plane-wave compounding has been developed for many biomedical applications. Most coherent-plane-wave compounding systems typically operate at 3-15 MHz, and the image resolution for this frequency range is not sufficient for visualizing microstructure tissues. Therefore, the purpose of this study was to implement a high-frequency ultrafast ultrasound imaging operating at 40 MHz. The plane-wave compounding imaging and conventional multifocus B-mode imaging were performed using the Field II toolbox of MATLAB in simulation study. In experiments, plane-wave compounding images were obtained from a 256 channel ultrasound research platform with a 40 MHz array transducer. All images were produced by point-spread functions and cyst phantoms. The in vivo experiment was performed from zebrafish. Since high-frequency ultrasound exhibits a lower penetration, chirp excitation was applied to increase the imaging depth in simulation. The simulation results showed that a lateral resolution of up to 66.93 μm and a contrast of up to 56.41 dB were achieved when using 75-angles plane waves in compounding imaging. The experimental results showed that a lateral resolution of up to 74.83 μm and a contrast of up to 44.62 dB were achieved when using 75-angles plane waves in compounding imaging. The dead zone and compounding noise are about 1.2 mm and 2.0 mm in depth for experimental compounding imaging, respectively. The structure of zebrafish heart was observed clearly using plane-wave compounding imaging. The use of fewer than 23 angles for compounding allowed a frame rate higher than 1000 frames per second. However, the compounding imaging exhibits a similar lateral resolution of about 72 μm as the angle of plane wave is higher than 10 angles. This study shows the highest operational frequency for ultrafast high-frame-rate ultrasound imaging. © 2017 American Association of Physicists in Medicine.

Vascular applications of contrast-enhanced ultrasound imaging.

PubMed

Mehta, Kunal S; Lee, Jake J; Taha, Ashraf G; Avgerinos, Efthymios; Chaer, Rabih A

2017-07-01

Contrast-enhanced ultrasound (CEUS) imaging is a powerful noninvasive modality offering numerous potential diagnostic and therapeutic applications in vascular medicine. CEUS imaging uses microbubble contrast agents composed of an encapsulating shell surrounding a gaseous core. These microbubbles act as nearly perfect intravascular reflectors of ultrasound energy and may be used to enhance the overall contrast and quality of ultrasound images. The purpose of this narrative review is to survey the current literature regarding CEUS imaging and discuss its diagnostic and therapeutic roles in current vascular and selected nonvascular applications. The PubMed, MEDLINE, and Embase databases were searched until July 2016 using the PubMed and Ovid Web-based search engines. The search terms used included contrast-enhanced, microbubble, ultrasound, carotid, aneurysm, and arterial. The diagnostic and therapeutic utility of CEUS imaging has grown exponentially, particularly in the realms of extracranial carotid arterial disease, aortic disease, and peripheral arterial disease. Studies have demonstrated that CEUS imaging is diagnostically superior to conventional ultrasound imaging in identifying vessel irregularities and measuring neovascularization to assess plaque vulnerability and end-muscle perfusion. Groups have begun to use microbubbles as agents in therapeutic applications for targeted drug and gene therapy delivery as well as for the enhancement of sonothrombolysis. The emerging technology of microbubbles and CEUS imaging holds considerable promise for cardiovascular medicine and cancer therapy given its diagnostic and therapeutic utility. Overall, with proper training and credentialing of technicians, the clinical implications are innumerable as microbubble technology is rapidly bursting onto the scene of cardiovascular medicine. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

An image registration based ultrasound probe calibration

NASA Astrophysics Data System (ADS)

Li, Xin; Kumar, Dinesh; Sarkar, Saradwata; Narayanan, Ram

2012-02-01

Reconstructed 3D ultrasound of prostate gland finds application in several medical areas such as image guided biopsy, therapy planning and dose delivery. In our application, we use an end-fire probe rotated about its axis to acquire a sequence of rotational slices to reconstruct 3D TRUS (Transrectal Ultrasound) image. The image acquisition system consists of an ultrasound transducer situated on a cradle directly attached to a rotational sensor. However, due to system tolerances, axis of probe does not align exactly with the designed axis of rotation resulting in artifacts in the 3D reconstructed ultrasound volume. We present a rigid registration based automatic probe calibration approach. The method uses a sequence of phantom images, each pair acquired at angular separation of 180 degrees and registers corresponding image pairs to compute the deviation from designed axis. A modified shadow removal algorithm is applied for preprocessing. An attribute vector is constructed from image intensity and a speckle-insensitive information-theoretic feature. We compare registration between the presented method and expert-corrected images in 16 prostate phantom scans. Images were acquired at multiple resolutions, and different misalignment settings from two ultrasound machines. Screenshots from 3D reconstruction are shown before and after misalignment correction. Registration parameters from automatic and manual correction were found to be in good agreement. Average absolute differences of translation and rotation between automatic and manual methods were 0.27 mm and 0.65 degree, respectively. The registration parameters also showed lower variability for automatic registration (pooled standard deviation σtranslation = 0.50 mm, σrotation = 0.52 degree) compared to the manual approach (pooled standard deviation σtranslation = 0.62 mm, σrotation = 0.78 degree).

Pulse Compression Techniques for Laser Generated Ultrasound

NASA Technical Reports Server (NTRS)

Anastasi, R. F.; Madaras, E. I.

1999-01-01

Laser generated ultrasound for nondestructive evaluation has an optical power density limit due to rapid high heating that causes material damage. This damage threshold limits the generated ultrasound amplitude, which impacts nondestructive evaluation inspection capability. To increase ultrasound signal levels and improve the ultrasound signal-to-noise ratio without exceeding laser power limitations, it is possible to use pulse compression techniques. The approach illustrated here uses a 150mW laser-diode modulated with a pseudo-random sequence and signal correlation. Results demonstrate the successful generation of ultrasonic bulk waves in aluminum and graphite-epoxy composite materials using a modulated low-power laser diode and illustrate ultrasound bandwidth control.

Non-Contact Optical Ultrasound Concept for Biomedical Imaging

DTIC Science & Technology

2016-11-03

Non -Contact Optical Ultrasound Concept for Biomedical Imaging Robert Haupt1, Charles Wynn1, Jonathan Fincke2, Shawn Zhang2, Brian Anthony2...results. Lastly, we present imaging capabilities using a non -contact laser ultrasound proof-of-concept system. Two and three dimensional time... non -contact, standoff optical ultrasound has the potential to provide a fixed reference measurement capability that minimizes operator variability as

Imaging By Ultrasound

PubMed Central

Kidney, Maria R.

1986-01-01

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

3D ultrafast ultrasound imaging in vivo.

PubMed

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

2014-10-07

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

Ultrasound Imaging Initiative

DTIC Science & Technology

2003-01-01

texture mapping hardware," IEEE Tranactions on Information Technology in Biomedicine, Submitted. [14] C.R. Castro Pareja , J.M. Jagadeesh and R. Shekhar...modulation in real-time three-dimensional sparse synthetic aperture ultrasound imaging systems "* Carlos R. Castro Pareja , Masters of Science, The Ohio...C.R. Castro Pareja , "An architecture for real-time image registration," M.S. Thesis, The Ohio State University, March 2002. 14. C.R. Castro Pareja , R

Multimedia systems in ultrasound image boundary detection and measurements

NASA Astrophysics Data System (ADS)

Pathak, Sayan D.; Chalana, Vikram; Kim, Yongmin

1997-05-01

Ultrasound as a medical imaging modality offers the clinician a real-time of the anatomy of the internal organs/tissues, their movement, and flow noninvasively. One of the applications of ultrasound is to monitor fetal growth by measuring biparietal diameter (BPD) and head circumference (HC). We have been working on automatic detection of fetal head boundaries in ultrasound images. These detected boundaries are used to measure BPD and HC. The boundary detection algorithm is based on active contour models and takes 32 seconds on an external high-end workstation, SUN SparcStation 20/71. Our goal has been to make this tool available within an ultrasound machine and at the same time significantly improve its performance utilizing multimedia technology. With the advent of high- performance programmable digital signal processors (DSP), the software solution within an ultrasound machine instead of the traditional hardwired approach or requiring an external computer is now possible. We have integrated our boundary detection algorithm into a programmable ultrasound image processor (PUIP) that fits into a commercial ultrasound machine. The PUIP provides both the high computing power and flexibility needed to support computationally-intensive image processing algorithms within an ultrasound machine. According to our data analysis, BPD/HC measurements made on PUIP lie within the interobserver variability. Hence, the errors in the automated BPD/HC measurements using the algorithm are on the same order as the average interobserver differences. On PUIP, it takes 360 ms to measure the values of BPD/HC on one head image. When processing multiple head images in sequence, it takes 185 ms per image, thus enabling 5.4 BPD/HC measurements per second. Reduction in the overall execution time from 32 seconds to a fraction of a second and making this multimedia system available within an ultrasound machine will help this image processing algorithm and other computer-intensive imaging

Ultrasound Backscatter Microscopy for Imaging of Oral Carcinoma

PubMed Central

Lam, Matthew; Chaudhari, Abhijit J.; Sun, Yang; Zhou, Feifei; Dobbie, Allison; Gandour-Edwards, Regina F.; Tinling, Steve P.; Farwell, D. Gregory; Monsky, Wayne L.; Shung, K. Kirk; Marcu, Laura

2013-01-01

Objectives Ultrasound backscatter microscopy (UBM), or ultrasound biomicroscopy, is a noninvasive, label-free, and ionizing radiation–free technique allowing high-resolution 3-dimensional structural imaging. The goal of this study was to evaluate UBM for resolving anatomic features associated with squamous cell carcinoma of the oral cavity. Methods The study was conducted in a hamster buccal pouch model. A carcinogen was topically applied to cheeks of 14 golden Syrian hamsters. Six additional hamsters served as healthy controls. A high-frequency (41 MHz, 6-mm focal depth, lateral and axial resolutions of 65 and 37 μm, respectively) UBM system was used for scanning the oral cavity after 14 weeks of carcinogen application. Histologic analyses were conducted on scanned regions. Results The histologic structure of buccal tissue and microvasculature networks could be visualized from the UBM images. Epithelial and mucosal hypertrophy and neoplastic changes were identified in animals subjected to the carcinogen. In animals with invasive squamous cell carcinoma, lesion development and destruction of the structural integrity of tissue layers were noted. Conclusions In this pilot study, UBM generated sufficient contrast for morphologic features associated with oral carcinoma compared to healthy tissue. This modality may present a practical technique for detection of oral neoplasms that is potentially translatable to humans. PMID:24065260

A Targeting Microbubble for Ultrasound Molecular Imaging

PubMed Central

Yeh, James Shue-Min; Sennoga, Charles A.; McConnell, Ellen; Eckersley, Robert; Tang, Meng-Xing; Nourshargh, Sussan; Seddon, John M.; Haskard, Dorian O.; Nihoyannopoulos, Petros

2015-01-01

Rationale Microbubbles conjugated with targeting ligands are used as contrast agents for ultrasound molecular imaging. However, they often contain immunogenic (strept)avidin, which impedes application in humans. Although targeting bubbles not employing the biotin-(strept)avidin conjugation chemistry have been explored, only a few reached the stage of ultrasound imaging in vivo, none were reported/evaluated to show all three of the following properties desired for clinical applications: (i) low degree of non-specific bubble retention in more than one non-reticuloendothelial tissue; (ii) effective for real-time imaging; and (iii) effective for acoustic quantification of molecular targets to a high degree of quantification. Furthermore, disclosures of the compositions and methodologies enabling reproduction of the bubbles are often withheld. Objective To develop and evaluate a targeting microbubble based on maleimide-thiol conjugation chemistry for ultrasound molecular imaging. Methods and Results Microbubbles with a previously unreported generic (non-targeting components) composition were grafted with anti-E-selectin F(ab’)2 using maleimide-thiol conjugation, to produce E-selectin targeting microbubbles. The resulting targeting bubbles showed high specificity to E-selectin in vitro and in vivo. Non-specific bubble retention was minimal in at least three non-reticuloendothelial tissues with inflammation (mouse heart, kidneys, cremaster). The bubbles were effective for real-time ultrasound imaging of E-selectin expression in the inflamed mouse heart and kidneys, using a clinical ultrasound scanner. The acoustic signal intensity of the targeted bubbles retained in the heart correlated strongly with the level of E-selectin expression (|r|≥0.8), demonstrating a high degree of non-invasive molecular quantification. Conclusions Targeting microbubbles for ultrasound molecular imaging, based on maleimide-thiol conjugation chemistry and the generic composition described

Adaptive texture filtering for defect inspection in ultrasound images

NASA Astrophysics Data System (ADS)

Zmola, Carl; Segal, Andrew C.; Lovewell, Brian; Nash, Charles

1993-05-01

The use of ultrasonic imaging to analyze defects and characterize materials is critical in the development of non-destructive testing and non-destructive evaluation (NDT/NDE) tools for manufacturing. To develop better quality control and reliability in the manufacturing environment advanced image processing techniques are useful. For example, through the use of texture filtering on ultrasound images, we have been able to filter characteristic textures from highly-textured C-scan images of materials. The materials have highly regular characteristic textures which are of the same resolution and dynamic range as other important features within the image. By applying texture filters and adaptively modifying their filter response, we have examined a family of filters for removing these textures.

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

PubMed

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

2017-06-01

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

Local binary pattern texture-based classification of solid masses in ultrasound breast images

NASA Astrophysics Data System (ADS)

Matsumoto, Monica M. S.; Sehgal, Chandra M.; Udupa, Jayaram K.

2012-03-01

Breast cancer is one of the leading causes of cancer mortality among women. Ultrasound examination can be used to assess breast masses, complementarily to mammography. Ultrasound images reveal tissue information in its echoic patterns. Therefore, pattern recognition techniques can facilitate classification of lesions and thereby reduce the number of unnecessary biopsies. Our hypothesis was that image texture features on the boundary of a lesion and its vicinity can be used to classify masses. We have used intensity-independent and rotation-invariant texture features, known as Local Binary Patterns (LBP). The classifier selected was K-nearest neighbors. Our breast ultrasound image database consisted of 100 patient images (50 benign and 50 malignant cases). The determination of whether the mass was benign or malignant was done through biopsy and pathology assessment. The training set consisted of sixty images, randomly chosen from the database of 100 patients. The testing set consisted of forty images to be classified. The results with a multi-fold cross validation of 100 iterations produced a robust evaluation. The highest performance was observed for feature LBP with 24 symmetrically distributed neighbors over a circle of radius 3 (LBP24,3) with an accuracy rate of 81.0%. We also investigated an approach with a score of malignancy assigned to the images in the test set. This approach provided an ROC curve with Az of 0.803. The analysis of texture features over the boundary of solid masses showed promise for malignancy classification in ultrasound breast images.

Adaptive mesh optimization and nonrigid motion recovery based image registration for wide-field-of-view ultrasound imaging.

PubMed

Tan, Chaowei; Wang, Bo; Liu, Paul; Liu, Dong

2008-01-01

Wide field of view (WFOV) imaging mode obtains an ultrasound image over an area much larger than the real time window normally available. As the probe is moved over the region of interest, new image frames are combined with prior frames to form a panorama image. Image registration techniques are used to recover the probe motion, eliminating the need for a position sensor. Speckle patterns, which are inherent in ultrasound imaging, change, or become decorrelated, as the scan plane moves, so we pre-smooth the image to reduce the effects of speckle in registration, as well as reducing effects from thermal noise. Because we wish to track the movement of features such as structural boundaries, we use an adaptive mesh over the entire smoothed image to home in on areas with feature. Motion estimation using blocks centered at the individual mesh nodes generates a field of motion vectors. After angular correction of motion vectors, we model the overall movement between frames as a nonrigid deformation. The polygon filling algorithm for precise, persistence-based spatial compounding constructs the final speckle reduced WFOV image.

Cavitation and contrast: the use of bubbles in ultrasound imaging and therapy.

PubMed

Stride, E P; Coussios, C C

2010-01-01

Microbubbles and cavitation are playing an increasingly significant role in both diagnostic and therapeutic applications of ultrasound. Microbubble ultrasound contrast agents have been in clinical use now for more than two decades, stimulating the development of a range of new contrast-specific imaging techniques which offer substantial benefits in echocardiography, microcirculatory imaging, and more recently, quantitative and molecular imaging. In drug delivery and gene therapy, microbubbles are being investigated/developed as vehicles which can be loaded with the required therapeutic agent, traced to the target site using diagnostic ultrasound, and then destroyed with ultrasound of higher intensity energy burst to release the material locally, thus avoiding side effects associated with systemic administration, e.g. of toxic chemotherapy. It has moreover been shown that the motion of the microbubbles increases the permeability of both individual cell membranes and the endothelium, thus enhancing therapeutic uptake, and can locally increase the activity of drugs by enhancing their transport across biologically inaccessible interfaces such as blood clots or solid tumours. In high-intensity focused ultrasound (HIFU) surgery and lithotripsy, controlled cavitation is being investigated as a means of increasing the speed and efficacy of the treatment. The aim of this paper is both to describe the key features of the physical behaviour of acoustically driven bubbles which underlie their effectiveness in biomedical applications and to review the current state of the art.

Simulation Study of Effects of the Blind Deconvolution on Ultrasound Image

NASA Astrophysics Data System (ADS)

He, Xingwu; You, Junchen

2018-03-01

Ultrasonic image restoration is an essential subject in Medical Ultrasound Imaging. However, without enough and precise system knowledge, some traditional image restoration methods based on the system prior knowledge often fail to improve the image quality. In this paper, we use the simulated ultrasound image to find the effectiveness of the blind deconvolution method for ultrasound image restoration. Experimental results demonstrate that the blind deconvolution method can be applied to the ultrasound image restoration and achieve the satisfactory restoration results without the precise prior knowledge, compared with the traditional image restoration method. And with the inaccurate small initial PSF, the results shows blind deconvolution could improve the overall image quality of ultrasound images, like much better SNR and image resolution, and also show the time consumption of these methods. it has no significant increasing on GPU platform.

Ultrasound Imaging of Muscle Contraction of the Tibialis Anterior in Patients with Facioscapulohumeral Dystrophy.

PubMed

Gijsbertse, Kaj; Goselink, Rianne; Lassche, Saskia; Nillesen, Maartje; Sprengers, André; Verdonschot, Nico; van Alfen, Nens; de Korte, Chris

2017-11-01

A need exists for biomarkers to diagnose, quantify and longitudinally follow facioscapulohumeral muscular dystrophy (FSHD) and many other neuromuscular disorders. Furthermore, the pathophysiological mechanisms leading to muscle weakness in most neuromuscular disorders are not completely understood. Dynamic ultrasound imaging (B-mode image sequences) in combination with speckle tracking is an easy, applicable and patient-friendly imaging tool to visualize and quantify muscle deformation. This dynamic information provides insight in the pathophysiological mechanisms and may help to distinguish the various stages of diseased muscle in FSHD. In this proof-of-principle study, we applied a speckle tracking technique to 2-D ultrasound image sequences to quantify the deformation of the tibialis anterior muscle in patients with FSHD and in healthy controls. The resulting deformation patterns were compared with muscle ultrasound echo intensity analysis (a measure of fat infiltration and dystrophy) and clinical outcome measures. Of the four FSHD patients, two patients had severe peroneal weakness and two patients had mild peroneal weakness on clinical examination. We found a markedly varied muscle deformation pattern between these groups: patients with severe peroneal weakness showed a different motion pattern of the tibialis anterior, with overall less displacement of the central tendon region, while healthy patients showed a non-uniform displacement pattern, with the central aponeurosis showing the largest displacement. Hence, dynamic muscle ultrasound of the tibialis anterior muscle in patients with FSHD revealed a distinctively different tissue deformation pattern among persons with and without tibialis anterior weakness. These findings could clarify the understanding of the pathophysiology of muscle weakness in FSHD patients. In addition, the change in muscle deformation shows good correlation with clinical measures and quantitative muscle ultrasound measurements. In

The feasibility of non-contact ultrasound for medical imaging.

PubMed

Clement, G T; Nomura, H; Adachi, H; Kamakura, T

2013-09-21

High intensity focused ultrasound in air may provide a means for medical and biological imaging without direct coupling of an ultrasound probe. In this study, an approach based on highly focused ultrasound in air is described and the feasibility of the technique is assessed. The overall method is based on the observations that (1) ultrasound in air has superior focusing ability and stronger nonlinear harmonic generation as compared to tissue propagation and (2) a tightly focused field directed into tissue causes point-like spreading that may be regarded as a source for generalized diffraction tomography. Simulations of a spherically-curved transducer are performed, where the transducer's radiation pattern is directed from air into tissue. It is predicted that a focal pressure of 162 dB (2.5 kPa) is sufficient to direct ultrasound through the body, and provide a small but measurable signal (∼1 mPa) upon exit. Based on the simulations, a 20 cm diameter array consisting of 298 transducers is constructed. For this feasibility study, a 40 kHz resonance frequency is selected based on the commercial availability of such transducers. The array is used to focus through water and acrylic phantoms, and the time history of the exiting signal is evaluated. Sufficient data are acquired to demonstrate a low-resolution tomographic reconstruction. Finally, to demonstrate the feasibility to record a signal in vivo, a 75 mm × 55 mm section of a human hand is imaged in a C-mode configuration.

Validation of Noninvasive In Vivo Compound Ultrasound Strain Imaging Using Histologic Plaque Vulnerability Features.

PubMed

Hansen, Hendrik H G; de Borst, Gert Jan; Bots, Michiel L; Moll, Frans L; Pasterkamp, Gerard; de Korte, Chris L

2016-11-01

Carotid plaque rupture is a major cause of stroke. Key issue for risk stratification is early identification of rupture-prone plaques. A noninvasive technique, compound ultrasound strain imaging, was developed providing high-resolution radial deformation/strain images of atherosclerotic plaques. This study aims at in vivo validation of compound ultrasound strain imaging in patients by relating the measured strains to typical features of vulnerable plaques derived from histology after carotid endarterectomy. Strains were measured in 34 severely stenotic (>70%) carotid arteries at the culprit lesion site within 48 hours before carotid endarterectomy. In all cases, the lumen-wall boundary was identifiable on B-mode ultrasound, and the imaged cross-section did not move out of the imaging plane from systole to diastole. After endarterectomy, the plaques were processed using a validated histology analysis technique. Locally elevated strain values were observed in regions containing predominantly components related to plaque vulnerability, whereas lower values were observed in fibrous, collagen-rich plaques. The median strain of the inner plaque layer (1 mm thickness) was significantly higher (P<0.01) for (fibro)atheromatous (n=20, strain=0.27%) than that for fibrous plaques (n=14, strain=-0.75%). Also, a significantly larger area percentage of the inner layer revealed strains above 0.5% for (fibro)atheromatous (45.30%) compared with fibrous plaques (31.59%). (Fibro)atheromatous plaques were detected with a sensitivity, specificity, positive predictive value, and negative predictive value of 75%, 86%, 88%, and 71%, respectively. Strain did not significantly correlate with fibrous cap thickness, smooth muscle cell, or macrophage concentration. Compound ultrasound strain imaging allows differentiating (fibro)atheromatous from fibrous carotid artery plaques. © 2016 American Heart Association, Inc.

Ultrasound image filtering using the mutiplicative model

NASA Astrophysics Data System (ADS)

Navarrete, Hugo; Frery, Alejandro C.; Sanchez, Fermin; Anto, Joan

2002-04-01

Ultrasound images, as a special case of coherent images, are normally corrupted with multiplicative noise i.e. speckle noise. Speckle noise reduction is a difficult task due to its multiplicative nature, but good statistical models of speckle formation are useful to design adaptive speckle reduction filters. In this article a new statistical model, emerging from the Multiplicative Model framework, is presented and compared to previous models (Rayleigh, Rice and K laws). It is shown that the proposed model gives the best performance when modeling the statistics of ultrasound images. Finally, the parameters of the model can be used to quantify the extent of speckle formation; this quantification is applied to adaptive speckle reduction filter design. The effectiveness of the filter is demonstrated on typical in-vivo log-compressed B-scan images obtained by a clinical ultrasound system.

Ultrasound strain imaging using Barker code

NASA Astrophysics Data System (ADS)

Peng, Hui; Tie, Juhong; Guo, Dequan

2017-01-01

Ultrasound strain imaging is showing promise as a new way of imaging soft tissue elasticity in order to help clinicians detect lesions or cancers in tissues. In this paper, Barker code is applied to strain imaging to improve its quality. Barker code as a coded excitation signal can be used to improve the echo signal-to-noise ratio (eSNR) in ultrasound imaging system. For the Baker code of length 13, the sidelobe level of the matched filter output is -22dB, which is unacceptable for ultrasound strain imaging, because high sidelobe level will cause high decorrelation noise. Instead of using the conventional matched filter, we use the Wiener filter to decode the Barker-coded echo signal to suppress the range sidelobes. We also compare the performance of Barker code and the conventional short pulse in simulation method. The simulation results demonstrate that the performance of the Wiener filter is much better than the matched filter, and Baker code achieves higher elastographic signal-to-noise ratio (SNRe) than the short pulse in low eSNR or great depth conditions due to the increased eSNR with it.

Ultrasound-Guided Renal Access for Percutaneous Nephrolithotomy: A Description of Three Novel Ultrasound-Guided Needle Techniques

PubMed Central

Chu, Carissa; Masic, Selma; Usawachintachit, Manint; Hu, Weiguo; Yang, Wenzeng; Stoller, Marshall; Li, Jianxing

2016-01-01

Abstract Ultrasound-guided renal access for percutaneous nephrolithotomy (PCNL) is a safe, effective, and low-cost procedure commonly performed worldwide, but a technique underutilized by urologists in the United States. The purpose of this article is to familiarize the practicing urologist with methods for ultrasound guidance for percutaneous renal access. We discuss two alternative techniques for gaining renal access for PCNL under ultrasound guidance. We also describe a novel technique of using the puncture needle to reposition residual stone fragments to avoid additional tract dilation. With appropriate training, ultrasound-guided renal access for PCNL can lead to reduced radiation exposure, accurate renal access, and excellent stone-free success rates and clinical outcomes. PMID:26414304

Pocket-sized versus standard ultrasound machines in abdominal imaging.

PubMed

Tse, K H; Luk, W H; Lam, M C

2014-06-01

The pocket-sized ultrasound machine has emerged as an invaluable tool for quick assessment in emergency and general practice settings. It is suitable for instant and quick assessment in cardiac imaging. However, its applicability in the imaging of other body parts has yet to be established. In this pictorial review, we compared the performance of the pocketsized ultrasound machine against the standard ultrasound machine for its image quality in common abdominal pathology.

A Computational Observer For Performing Contrast-Detail Analysis Of Ultrasound Images

NASA Astrophysics Data System (ADS)

Lopez, H.; Loew, M. H.

1988-06-01

Contrast-Detail (C/D) analysis allows the quantitative determination of an imaging system's ability to display a range of varying-size targets as a function of contrast. Using this technique, a contrast-detail plot is obtained which can, in theory, be used to compare image quality from one imaging system to another. The C/D plot, however, is usually obtained by using data from human observer readings. We have shown earlier(7) that the performance of human observers in the task of threshold detection of simulated lesions embedded in random ultrasound noise is highly inaccurate and non-reproducible for untrained observers. We present an objective, computational method for the determination of the C/D curve for ultrasound images. This method utilizes digital images of the C/D phantom developed at CDRH, and lesion-detection algorithms that simulate the Bayesian approach using the likelihood function for an ideal observer. We present the results of this method, and discuss the relationship to the human observer and to the comparability of image quality between systems.

Multifunctional microbubbles and nanobubbles for photoacoustic and ultrasound imaging

PubMed Central

Kim, Chulhong; Qin, Ruogu; Xu, Jeff S.; Wang, Lihong V.; Xu, Ronald

2010-01-01

We develop a novel dual-modal contrast agent—encapsulated-ink poly(lactic-co-glycolic acid) (PLGA) microbubbles and nanobubbles—for photoacoustic and ultrasound imaging. Soft gelatin phantoms with embedded tumor simulators of encapsulated-ink PLGA microbubbles and nanobubbles in various concentrations are clearly shown in both photoacoustic and ultrasound images. In addition, using photoacoustic imaging, we successfully image the samples positioned below 1.8-cm-thick chicken breast tissues. Potentially, simultaneous photoacoustic and ultrasound imaging enhanced by encapsulated-dye PLGA microbubbles or nanobubbles can be a valuable tool for intraoperative assessment of tumor boundaries and therapeutic margins. PMID:20210423

Characterization of Contrast Agent Microbubbles for Ultrasound Imaging and Therapy Research.

PubMed

Mulvana, Helen; Browning, Richard J; Luan, Ying; de Jong, Nico; Tang, Meng-Xing; Eckersley, Robert J; Stride, Eleanor

2017-01-01

The high efficiency with which gas microbubbles can scatter ultrasound compared with the surrounding blood pool or tissues has led to their widespread employment as contrast agents in ultrasound imaging. In recent years, their applications have been extended to include super-resolution imaging and the stimulation of localized bio-effects for therapy. The growing exploitation of contrast agents in ultrasound and in particular these recent developments have amplified the need to characterize and fully understand microbubble behavior. The aim in doing so is to more fully exploit their utility for both diagnostic imaging and potential future therapeutic applications. This paper presents the key characteristics of microbubbles that determine their efficacy in diagnostic and therapeutic applications and the corresponding techniques for their measurement. In each case, we have presented information regarding the methods available and their respective strengths and limitations, with the aim of presenting information relevant to the selection of appropriate characterization methods. First, we examine methods for determining the physical properties of microbubble suspensions and then techniques for acoustic characterization of both suspensions and single microbubbles. The next section covers characterization of microbubbles as therapeutic agents, including as drug carriers for which detailed understanding of their surface characteristics and drug loading capacity is required. Finally, we discuss the attempts that have been made to allow comparison across the methods employed by various groups to characterize and describe their microbubble suspensions and promote wider discussion and comparison of microbubble behavior.

In Vivo Multiparametric Ultrasound Imaging of Structural and Functional Tumor Modifications during Therapy.

PubMed

Dizeux, Alexandre; Payen, Thomas; Le Guillou-Buffello, Delphine; Comperat, Eva; Gennisson, Jean-Luc; Tanter, Mickael; Oelze, Michael; Bridal, S Lori

2017-09-01

Longitudinal imaging techniques are needed that can meaningfully probe the tumor microenvironment and its spatial heterogeneity. Contrast-enhanced ultrasound, shear wave elastography and quantitative ultrasound are ultrasound-based techniques that provide information on the vascular function and micro-/macroscopic tissue structure. Modifications of the tumor microenvironment induced by cytotoxic and anti-angiogenic molecules in ectopic murine Lewis lung carcinoma tumors were monitored. The most heterogenous structures were found in tumors treated with anti-angiogenic drug that simultaneously accumulated the highest levels of necrosis and fibrosis. The anti-angiogenic group presented the highest number of correlations between parameters related to vascular function and those related to the micro-/macrostructure of the tumor microenvironment. Results suggest how patterns of multiparametric ultrasound modifications can be related to provide a more insightful marker of changes occurring within tumors during therapy. Copyright © 2017. Published by Elsevier Inc.

Evaluation of multimodality imaging using image fusion with ultrasound tissue elasticity imaging in an experimental animal model.

PubMed

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

2014-01-01

To evaluate the ultrasound tissue elasticity imaging by comparison to multimodality imaging using image fusion with Magnetic Resonance Imaging (MRI) and conventional grey scale imaging with additional elasticity-ultrasound in an experimental small-animal-squamous-cell carcinoma-model for the assessment of tissue morphology. Human hypopharynx carcinoma cells were subcutaneously injected into the left flank of 12 female athymic nude rats. After 10 days (SD ± 2) of subcutaneous tumor growth, sonographic grey scale including elasticity imaging and MRI measurements were performed using a high-end ultrasound system and a 3T MR. For image fusion the contrast-enhanced MRI DICOM data set was uploaded in the ultrasonic device which has a magnetic field generator, a linear array transducer (6-15 MHz) and a dedicated software package (GE Logic E9), that can detect transducers by means of a positioning system. Conventional grey scale and elasticity imaging were integrated in the image fusion examination. After successful registration and image fusion the registered MR-images were simultaneously shown with the respective ultrasound sectional plane. Data evaluation was performed using the digitally stored video sequence data sets by two experienced radiologist using a modified Tsukuba Elasticity score. The colors "red and green" are assigned for an area of soft tissue, "blue" indicates hard tissue. In all cases a successful image fusion and plan registration with MRI and ultrasound imaging including grey scale and elasticity imaging was possible. The mean tumor volume based on caliper measurements in 3 dimensions was ~323 mm3. 4/12 rats were evaluated with Score I, 5/12 rates were evaluated with Score II, 3/12 rates were evaluated with Score III. There was a close correlation in the fused MRI with existing small necrosis in the tumor. None of the scored II or III lesions was visible by conventional grey scale. The comparison of ultrasound tissue elasticity imaging enables a

Interstitial ablation and imaging of soft tissue using miniaturized ultrasound arrays

NASA Astrophysics Data System (ADS)

Makin, Inder R. S.; Gallagher, Laura A.; Mast, T. Douglas; Runk, Megan M.; Faidi, Waseem; Barthe, Peter G.; Slayton, Michael H.

2004-05-01

A potential alternative to extracorporeal, noninvasive HIFU therapy is minimally invasive, interstitial ultrasound ablation that can be performed laparoscopically or percutaneously. Research in this area at Guided Therapy Systems and Ethicon Endo-Surgery has included development of miniaturized (~3 mm diameter) linear ultrasound arrays capable of high power for bulk tissue ablation as well as broad bandwidth for imaging. An integrated control system allows therapy planning and automated treatment guided by real-time interstitial B-scan imaging. Image quality, challenging because of limited probe dimensions and channel count, is aided by signal processing techniques that improve image definition and contrast. Simulations of ultrasonic heat deposition, bio-heat transfer, and tissue modification provide understanding and guidance for development of treatment strategies. Results from in vitro and in vivo ablation experiments, together with corresponding simulations, will be described. Using methods of rotational scanning, this approach is shown to be capable of clinically relevant ablation rates and volumes.

Ultrasound functional imaging in an ex vivo beating porcine heart platform

NASA Astrophysics Data System (ADS)

Petterson, Niels J.; Fixsen, Louis S.; Rutten, Marcel C. M.; Pijls, Nico H. J.; van de Vosse, Frans N.; Lopata, Richard G. P.

2017-12-01

In recent years, novel ultrasound functional imaging (UFI) techniques have been introduced to assess cardiac function by measuring, e.g. cardiac output (CO) and/or myocardial strain. Verification and reproducibility assessment in a realistic setting remain major issues. Simulations and phantoms are often unrealistic, whereas in vivo measurements often lack crucial hemodynamic parameters or ground truth data, or suffer from the large physiological and clinical variation between patients when attempting clinical validation. Controlled validation in certain pathologies is cumbersome and often requires the use of lab animals. In this study, an isolated beating pig heart setup was adapted and used for performance assessment of UFI techniques such as volume assessment and ultrasound strain imaging. The potential of performing verification and reproducibility studies was demonstrated. For proof-of-principle, validation of UFI in pathological hearts was examined. Ex vivo porcine hearts (n  =  6, slaughterhouse waste) were resuscitated and attached to a mock circulatory system. Radio frequency ultrasound data of the left ventricle were acquired in five short axis views and one long axis view. Based on these slices, the CO was measured, where verification was performed using flow sensor measurements in the aorta. Strain imaging was performed providing radial, circumferential and longitudinal strain to assess reproducibility and inter-subject variability under steady conditions. Finally, strains in healthy hearts were compared to a heart with an implanted left ventricular assist device, simulating a failing, supported heart. Good agreement between ultrasound and flow sensor based CO measurements was found. Strains were highly reproducible (intraclass correlation coefficients  >0.8). Differences were found due to biological variation and condition of the hearts. Strain magnitude and patterns in the assisted heart were available for different pump action, revealing

Optical Fluorescent Imaging to Monitor Temporal Effects of Microbubble-Mediated Ultrasound Therapy

PubMed Central

Sorace, Anna G.; Saini, Reshu; Rosenthal, Eben; Warram, Jason M.; Zinn, Kurt R.; Hoyt, Kenneth

2013-01-01

Microbubble-mediated ultrasound therapy can noninvasively enhance drug delivery to localized regions in the body. This technique can be beneficial in cancer therapy, but currently there are limitations to tracking the therapeutic effects. The purpose of this experiment was to investigate the potential of fluorescent imaging for monitoring the temporal effects of microbubble-mediated ultrasound therapy. Mice were implanted with 2LMP breast cancer cells. The animals underwent microbubble-mediated ultrasound therapy in the presence of Cy5.5 fluorescent-labeled IgG antibody (large molecule) or Cy5.5 dye (small molecule) and microbubble contrast agents. Control animals were administered fluorescent molecules only. Animals were transiently imaged in vivo at 1, 10, 30, and 60 min post therapy using a small animal optical imaging system. Tumors were excised and analyzed ex vivo. Tumors were homogenized and emulsion imaged for Cy5.5 fluorescence. Monitoring in vivo results showed significant influx of dye into the tumor (p < 0.05) using the small molecule, but not in the large molecule group (p > 0.05). However, after tumor emulsion, significantly higher dye concentration was detected in therapy group tumors for both small and large molecule groups in comparison to their control counterparts (p < 0.01). This paper explores a noninvasive optical imaging method for monitoring the effects of microbubble-mediated ultrasound therapy in a cancer model. It provides temporal information following the process of increasing extravasation of molecules into target tumors. PMID:23357902

Optical fluorescent imaging to monitor temporal effects of microbubble-mediated ultrasound therapy.

PubMed

Sorace, Anna G; Saini, Reshu; Rosenthal, Eben; Warram, Jason M; Zinn, Kurt R; Hoyt, Kenneth

2013-02-01

Microbubble-mediated ultrasound therapy can noninvasively enhance drug delivery to localized regions in the body. This technique can be beneficial in cancer therapy, but currently there are limitations to tracking the therapeutic effects. The purpose of this experiment was to investigate the potential of fluorescent imaging for monitoring the temporal effects of microbubble-mediated ultrasound therapy. Mice were implanted with 2LMP breast cancer cells. The animals underwent microbubble-mediated ultrasound therapy in the presence of Cy5.5 fluorescent-labeled IgG antibody (large molecule) or Cy5.5 dye (small molecule) and microbubble contrast agents. Control animals were administered fluorescent molecules only. Animals were transiently imaged in vivo at 1, 10, 30, and 60 min post therapy using a small animal optical imaging system. Tumors were excised and analyzed ex vivo. Tumors were homogenized and emulsion imaged for Cy5.5 fluorescence. Monitoring in vivo results showed significant influx of dye into the tumor (p < 0.05) using the small molecule, but not in the large molecule group (p > 0.05). However, after tumor emulsion, significantly higher dye concentration was detected in therapy group tumors for both small and large molecule groups in comparison to their control counterparts (p <0.01). This paper explores a noninvasive optical imaging method for monitoring the effects of microbubble-mediated ultrasound therapy in a cancer model. It provides temporal information following the process of increasing extravasation of molecules into target tumors.

Group-wise feature-based registration of CT and ultrasound images of spine

NASA Astrophysics Data System (ADS)

Rasoulian, Abtin; Mousavi, Parvin; Hedjazi Moghari, Mehdi; Foroughi, Pezhman; Abolmaesumi, Purang

2010-02-01

Registration of pre-operative CT and freehand intra-operative ultrasound of lumbar spine could aid surgeons in the spinal needle injection which is a common procedure for pain management. Patients are always in a supine position during the CT scan, and in the prone or sitting position during the intervention. This leads to a difference in the spinal curvature between the two imaging modalities, which means a single rigid registration cannot be used for all of the lumbar vertebrae. In this work, a method for group-wise registration of pre-operative CT and intra-operative freehand 2-D ultrasound images of the lumbar spine is presented. The approach utilizes a pointbased registration technique based on the unscented Kalman filter, taking as input segmented vertebrae surfaces in both CT and ultrasound data. Ultrasound images are automatically segmented using a dynamic programming approach, while the CT images are semi-automatically segmented using thresholding. Since the curvature of the spine is different between the pre-operative and the intra-operative data, the registration approach is designed to simultaneously align individual groups of points segmented from each vertebra in the two imaging modalities. A biomechanical model is used to constrain the vertebrae transformation parameters during the registration and to ensure convergence. The mean target registration error achieved for individual vertebrae on five spine phantoms generated from CT data of patients, is 2.47 mm with standard deviation of 1.14 mm.

Robot-assisted ultrasound imaging: overview and development of a parallel telerobotic system.

PubMed

Monfaredi, Reza; Wilson, Emmanuel; Azizi Koutenaei, Bamshad; Labrecque, Brendan; Leroy, Kristen; Goldie, James; Louis, Eric; Swerdlow, Daniel; Cleary, Kevin

2015-02-01

Ultrasound imaging is frequently used in medicine. The quality of ultrasound images is often dependent on the skill of the sonographer. Several researchers have proposed robotic systems to aid in ultrasound image acquisition. In this paper we first provide a short overview of robot-assisted ultrasound imaging (US). We categorize robot-assisted US imaging systems into three approaches: autonomous US imaging, teleoperated US imaging, and human-robot cooperation. For each approach several systems are introduced and briefly discussed. We then describe a compact six degree of freedom parallel mechanism telerobotic system for ultrasound imaging developed by our research team. The long-term goal of this work is to enable remote ultrasound scanning through teleoperation. This parallel mechanism allows for both translation and rotation of an ultrasound probe mounted on the top plate along with force control. Our experimental results confirmed good mechanical system performance with a positioning error of < 1 mm. Phantom experiments by a radiologist showed promising results with good image quality.

Microfluidics-based microbubbles in methylene blue solution for photoacoustic and ultrasound imaging

NASA Astrophysics Data System (ADS)

Das, Dhiman; Sivasubramanian, Kathyayini; Yang, Chun; Pramanik, Manojit

2018-02-01

Contrast agents which can be used for more than one bio-imaging technique has gained a lot of attention from researchers in recent years. In this work, a microfluidic device employing a flow-focusing junction, is used for the continuous generation of monodisperse nitrogen microbubbles in methylene blue, an optically absorbing organic dye, for dual-modal photoacoustic and ultrasound imaging. Using an external phase of polyoxyethylene glycol 40 stearate (PEG 40), a non-ionic surfactant, and 50% glycerol solution at a flow rate of 1 ml/hr and gas pressure at 1.75 bar, monodisperse nitrogen microbubbles of diameter 7 microns were obtained. The external phase also contained methylene blue hydrate at a concentration of 1 gm/litre. The monodisperse microbubbles produced a strong ultrasound signal as expected. It was observed that the signal-to-noise (SNR) ratio of the photoacoustic signal for the methylene blue solution in the presence of the monodisperse microbubbles was 68.6% lower than that of methylene blue solution in the absence of microbubbles. This work is of significance because using microfluidics, we can precisely control the bubbles' production rate and bubble size which increases ultrasound imaging efficiency. A uniform size distribution of the bubbles will have narrower resonance frequency bandwidth which will respond well to specific ultrasound frequencies.

Quantitative ultrasound imaging for monitoring in situ high-intensity focused ultrasound exposure.

PubMed

Ghoshal, Goutam; Kemmerer, Jeremy P; Karunakaran, Chandra; Abuhabsah, Rami; Miller, Rita J; Sarwate, Sandhya; Oelze, Michael L

2014-10-01

Quantitative ultrasound (QUS) imaging is hypothesized to map temperature elevations induced in tissue with high spatial and temporal resolution. To test this hypothesis, QUS techniques were examined to monitor high-intensity focused ultrasound (HIFU) exposure of tissue. In situ experiments were conducted on mammary adenocarcinoma tumors grown in rats and lesions were formed using a HIFU system. A thermocouple was inserted into the tumor to provide estimates of temperature at one location. Backscattered time-domain waveforms from the tissue during exposure were recorded using a clinical ultrasonic imaging system. Backscatter coefficients were estimated using a reference phantom technique. Two parameters were estimated from the backscatter coefficient (effective scatterer diameter (ESD) and effective acoustic concentration (EAC). The changes in the average parameters in the regions corresponding to the HIFU focus over time were correlated to the temperature readings from the thermocouple. The changes in the EAC parameter were consistently correlated to temperature during both heating and cooling of the tumors. The changes in the ESD did not have a consistent trend with temperature. The mean ESD and EAC before exposure were 120 ± 16 μm and 32 ± 3 dB/cm3, respectively, and changed to 144 ± 9 μm and 51 ± 7 dB/cm3, respectively, just before the last HIFU pulse was delivered to the tissue. After the tissue cooled down to 37 °C, the mean ESD and EAC were 126 ± 8 μm and 35 ± 4 dB/cm3, respectively. Peak temperature in the range of 50-60 °C was recorded by a thermocouple placed just behind the tumor. These results suggest that QUS techniques have the potential to be used for non-invasive monitoring of HIFU exposure. © The Author(s) 2014.

Twofold processing for denoising ultrasound medical images.

PubMed

Kishore, P V V; Kumar, K V V; Kumar, D Anil; Prasad, M V D; 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 speckle and also inducing object of interest blurring. The second fold process initiates to restore object boundaries and texture with adaptive wavelet fusion. The degraded object restoration in block thresholded US image is carried through wavelet coefficient fusion of object in original US mage and block thresholded US image. Fusion rules and wavelet decomposition levels are made adaptive for each block using gradient histograms with normalized differential mean (NDF) to introduce highest level of contrast between the denoised pixels and the object pixels in the resultant image. Thus the proposed twofold methods are named as adaptive NDF block fusion with hard and soft thresholding (ANBF-HT and ANBF-ST). The results indicate visual quality improvement to an interesting level with the proposed twofold processing, where the first fold removes noise and second fold restores object properties. Peak signal to noise ratio (PSNR), normalized cross correlation coefficient (NCC), edge strength (ES), image quality Index (IQI) and structural similarity index (SSIM), measure the quantitative quality of the twofold processing technique. Validation of the proposed method is done by comparing with anisotropic diffusion (AD), total variational filtering (TVF) and empirical mode decomposition (EMD) for enhancement of US images. The US images are provided by AMMA hospital radiology labs at Vijayawada, India.

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

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

Tanter, M.

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

Cost-Effectiveness Comparison of Imaging-Guided Prostate Biopsy Techniques: Systematic Transrectal Ultrasound, Direct In-Bore MRI, and Image Fusion.

PubMed

Venderink, Wulphert; Govers, Tim M; de Rooij, Maarten; Fütterer, Jurgen J; Sedelaar, J P Michiel

2017-05-01

Three commonly used prostate biopsy approaches are systematic transrectal ultrasound guided, direct in-bore MRI guided, and image fusion guided. The aim of this study was to calculate which strategy is most cost-effective. A decision tree and Markov model were developed to compare cost-effectiveness. Literature review and expert opinion were used as input. A strategy was deemed cost-effective if the costs of gaining one quality-adjusted life year (incremental cost-effectiveness ratio) did not exceed the willingness-to-pay threshold of €80,000 (≈$85,000 in January 2017). A base case analysis was performed to compare systematic transrectal ultrasound- and image fusion-guided biopsies. Because of a lack of appropriate literature regarding the accuracy of direct in-bore MRI-guided biopsy, a threshold analysis was performed. The incremental cost-effectiveness ratio for fusion-guided biopsy compared with systematic transrectal ultrasound-guided biopsy was €1386 ($1470) per quality-adjusted life year gained, which was below the willingness-to-pay threshold and thus assumed cost-effective. If MRI findings are normal in a patient with clinically significant prostate cancer, the sensitivity of direct in-bore MRI-guided biopsy has to be at least 88.8%. If that is the case, the incremental cost-effectiveness ratio is €80,000 per quality-adjusted life year gained and thus cost-effective. Fusion-guided biopsy seems to be cost-effective compared with systematic transrectal ultrasound-guided biopsy. Future research is needed to determine whether direct in-bore MRI-guided biopsy is the best pathway; in this study a threshold was calculated at which it would be cost-effective.

Quantitative Ultrasound for Nondestructive Characterization of Engineered Tissues and Biomaterials

PubMed Central

Dalecki, Diane; Mercado, Karla P.; Hocking, Denise C.

2015-01-01

Non-invasive, non-destructive technologies for imaging and quantitatively monitoring the development of artificial tissues are critical for the advancement of tissue engineering. Current standard techniques for evaluating engineered tissues, including histology, biochemical assays and mechanical testing, are destructive approaches. Ultrasound is emerging as a valuable tool for imaging and quantitatively monitoring the properties of engineered tissues and biomaterials longitudinally during fabrication and post-implantation. Ultrasound techniques are rapid, non-invasive, non-destructive and can be easily integrated into sterile environments necessary for tissue engineering. Furthermore, high-frequency quantitative ultrasound techniques can enable volumetric characterization of the structural, biological, and mechanical properties of engineered tissues during fabrication and post-implantation. This review provides an overview of ultrasound imaging, quantitative ultrasound techniques, and elastography, with representative examples of applications of these ultrasound-based techniques to the field of tissue engineering. PMID:26581347

Rayleigh-maximum-likelihood bilateral filter for ultrasound image enhancement.

PubMed

Li, Haiyan; Wu, Jun; Miao, Aimin; Yu, Pengfei; Chen, Jianhua; Zhang, Yufeng

2017-04-17

Ultrasound imaging plays an important role in computer diagnosis since it is non-invasive and cost-effective. However, ultrasound images are inevitably contaminated by noise and speckle during acquisition. Noise and speckle directly impact the physician to interpret the images and decrease the accuracy in clinical diagnosis. Denoising method is an important component to enhance the quality of ultrasound images; however, several limitations discourage the results because current denoising methods can remove noise while ignoring the statistical characteristics of speckle and thus undermining the effectiveness of despeckling, or vice versa. In addition, most existing algorithms do not identify noise, speckle or edge before removing noise or speckle, and thus they reduce noise and speckle while blurring edge details. Therefore, it is a challenging issue for the traditional methods to effectively remove noise and speckle in ultrasound images while preserving edge details. To overcome the above-mentioned limitations, a novel method, called Rayleigh-maximum-likelihood switching bilateral filter (RSBF) is proposed to enhance ultrasound images by two steps: noise, speckle and edge detection followed by filtering. Firstly, a sorted quadrant median vector scheme is utilized to calculate the reference median in a filtering window in comparison with the central pixel to classify the target pixel as noise, speckle or noise-free. Subsequently, the noise is removed by a bilateral filter and the speckle is suppressed by a Rayleigh-maximum-likelihood filter while the noise-free pixels are kept unchanged. To quantitatively evaluate the performance of the proposed method, synthetic ultrasound images contaminated by speckle are simulated by using the speckle model that is subjected to Rayleigh distribution. Thereafter, the corrupted synthetic images are generated by the original image multiplied with the Rayleigh distributed speckle of various signal to noise ratio (SNR) levels and

Learning-based scan plane identification from fetal head ultrasound images

NASA Astrophysics Data System (ADS)

Liu, Xiaoming; Annangi, Pavan; Gupta, Mithun; Yu, Bing; Padfield, Dirk; Banerjee, Jyotirmoy; Krishnan, Kajoli

2012-03-01

Acquisition of a clinically acceptable scan plane is a pre-requisite for ultrasonic measurement of anatomical features from B-mode images. In obstetric ultrasound, measurement of gestational age predictors, such as biparietal diameter and head circumference, is performed at the level of the thalami and cavum septum pelucidi. In an accurate scan plane, the head can be modeled as an ellipse, the thalami looks like a butterfly, the cavum appears like an empty box and the falx is a straight line along the major axis of a symmetric ellipse inclined either parallel to or at small angles to the probe surface. Arriving at the correct probe placement on the mother's belly to obtain an accurate scan plane is a task of considerable challenge especially for a new user of ultrasound. In this work, we present a novel automated learning-based algorithm to identify an acceptable fetal head scan plane. We divide the problem into cranium detection and a template matching to capture the composite "butterfly" structure present inside the head, which mimics the visual cues used by an expert. The algorithm uses the stateof- the-art Active Appearance Models techniques from the image processing and computer vision literature and tie them to presence or absence of the inclusions within the head to automatically compute a score to represent the goodness of a scan plane. This automated technique can be potentially used to train and aid new users of ultrasound.

Needle tip visibility in 3D ultrasound images

NASA Astrophysics Data System (ADS)

Arif, Muhammad; Moelker, Adriaan; van Walsum, Theo

2017-03-01

Needle visibility is of crucial importance for ultrasound guided interventional procedures. However, several factors, such as shadowing by bone or gas and tissue echogenic properties similar to needles, may compromise needle visibility. Additionally, small angle between the ultrasound beam and the needle, as well as small gauged needles may reduce visibility. Variety in needle tips design may also affect needle visibility. Whereas several studies have investigated needle visibility in 2D ultrasound imaging, no data is available for 3D ultrasound imaging, a modality that has great potential for image guidance interventions1. In this study, we evaluated needle visibility using a 3D ultrasound transducer. We examined different needles in a tissue mimicking liver phantom at three angles (200, 550 and 900) and quantify their visibility. The liver phantom was made by 5% polyvinyl alcohol solution containing 1% Silica gel particles to act as ultrasound scattering particles. We used four needles; two biopsy needles (Quick core 14G and 18G), one Ablation needle (Radiofrequency Ablation 17G), and Initial puncture needle (IP needle 17G). The needle visibility was quantified by calculating contrast to noise ratio. The results showed that the visibility for all needles were almost similar at large angles. However the difference in visibility at lower angles is more prominent. Furthermore, the visibility increases with the increase in angle of ultrasound beam with needles.

Assessment of using ultrasound images as prior for diffuse optical tomography regularization matrix

NASA Astrophysics Data System (ADS)

Althobaiti, Murad; Vavadi, Hamed; Zhu, Quing

2017-02-01

Imaging of tissue with Ultrasound-guided diffuse optical tomography (DOT) is a rising imaging technique to map hemoglobin concentrations within tissue for breast cancer detection and diagnosis. Near-infrared optical imaging received a lot of attention in research as a possible technique to be used for such purpose especially for breast tumors. Since DOT images contrast is closely related to oxygenation and deoxygenating of the hemoglobin, which is an important factor in differentiating malignant and benign tumors. One of the optical imaging modalities used is the diffused optical tomography (DOT); which probes deep scattering tissue (1-5cm) by NIR optical source-detector probe and detects NIR photons in the diffusive regime. The photons in the diffusive regime usually reach the detector without significant information about their source direction and the propagation path. Because of that, the optical reconstruction problem of the medium characteristics is ill-posed even with the tomography and Back-projection techniques. The accurate recovery of images requires an effective image reconstruction method. Here, we illustrate a method in which ultrasound images are encoded as prior for regularization of the inversion matrix. Results were evaluated using phantom experiments of low and high absorption contrasts. This method improves differentiation between the low and the high contrasts targets. Ultimately, this method could improve malignant and benign cases by increasing reconstructed absorption ratio of malignant to benign. Besides that, the phantom results show improvements in target shape as well as the spatial resolution of the DOT reconstructed images.

Improved Contrast-Enhanced Ultrasound Imaging With Multiplane-Wave Imaging.

PubMed

Gong, Ping; Song, Pengfei; Chen, Shigao

2018-02-01

Contrast-enhanced ultrasound (CEUS) imaging has great potential for use in new ultrasound clinical applications such as myocardial perfusion imaging and abdominal lesion characterization. In CEUS imaging, contrast agents (i.e., microbubbles) are used to improve contrast between blood and tissue because of their high nonlinearity under low ultrasound pressure. However, the quality of CEUS imaging sometimes suffers from a low signal-to-noise ratio (SNR) in deeper imaging regions when a low mechanical index (MI) is used to avoid microbubble disruption, especially for imaging at off-resonance transmit frequencies. In this paper, we propose a new strategy of combining CEUS sequences with the recently proposed multiplane-wave (MW) compounding method to improve the SNR of CEUS in deeper imaging regions without increasing MI or sacrificing frame rate. The MW-CEUS method emits multiple Hadamard-coded CEUS pulses in each transmission event (i.e., pulse-echo event). The received echo signals first undergo fundamental bandpass filtering (i.e., the filter is centered on the transmit frequency) to eliminate the microbubble's second-harmonic signals because they cannot be encoded by pulse inversion. The filtered signals are then Hadamard decoded and realigned in fast time to recover the signals as they would have been obtained using classic CEUS pulses, followed by designed recombination to cancel the linear tissue responses. The MW-CEUS method significantly improved contrast-to-tissue ratio and SNR of CEUS imaging by transmitting longer coded pulses. The image resolution was also preserved. The microbubble disruption ratio and motion artifacts in MW-CEUS were similar to those of classic CEUS imaging. In addition, the MW-CEUS sequence can be adapted to other transmission coding formats. These properties of MW-CEUS can potentially facilitate CEUS imaging for many clinical applications, especially assessing deep abdominal organs or the heart.

Human placental vasculature imaging using an LED-based photoacoustic/ultrasound imaging system

NASA Astrophysics Data System (ADS)

Maneas, Efthymios; Xia, Wenfeng; Kuniyil Ajith Singh, Mithun; Sato, Naoto; Agano, Toshitaka; Ourselin, Sebastien; West, Simeon J.; David, Anna L.; Vercauteren, Tom; Desjardins, Adrien E.

2018-02-01

Minimally invasive fetal interventions, such as those used for therapy of twin-to-twin transfusion syndrome (TTTS), require accurate image guidance to optimise patient outcomes. Currently, TTTS can be treated fetoscopically by identifying anastomosing vessels on the chorionic (fetal) placental surface, and then performing photocoagulation. Incomplete photocoagulation increases the risk of procedure failure. Photoacoustic imaging can provide contrast for both haemoglobin concentration and oxygenation, and in this study, it was hypothesised that it can resolve chorionic placental vessels. We imaged a term human placenta that was collected after caesarean section delivery using a photoacoustic/ultrasound system (AcousticX) that included light emitting diode (LED) arrays for excitation light and a linear-array ultrasound imaging probe. Two-dimensional (2D) co-registered photoacoustic and B-mode pulse-echo ultrasound images were acquired and displayed in real-time. Translation of the imaging probe enabled 3D imaging. This feasibility study demonstrated that photoacoustic imaging can be used to visualise chorionic placental vasculature, and that it has strong potential to guide minimally invasive fetal interventions.

Multiplane wave imaging increases signal-to-noise ratio in ultrafast ultrasound imaging.

PubMed

Tiran, Elodie; Deffieux, Thomas; Correia, Mafalda; Maresca, David; Osmanski, Bruno-Felix; Sieu, Lim-Anna; Bergel, Antoine; Cohen, Ivan; Pernot, Mathieu; Tanter, Mickael

2015-11-07

Ultrafast imaging using plane or diverging waves has recently enabled new ultrasound imaging modes with improved sensitivity and very high frame rates. Some of these new imaging modalities include shear wave elastography, ultrafast Doppler, ultrafast contrast-enhanced imaging and functional ultrasound imaging. Even though ultrafast imaging already encounters clinical success, increasing even more its penetration depth and signal-to-noise ratio for dedicated applications would be valuable. Ultrafast imaging relies on the coherent compounding of backscattered echoes resulting from successive tilted plane waves emissions; this produces high-resolution ultrasound images with a trade-off between final frame rate, contrast and resolution. In this work, we introduce multiplane wave imaging, a new method that strongly improves ultrafast images signal-to-noise ratio by virtually increasing the emission signal amplitude without compromising the frame rate. This method relies on the successive transmissions of multiple plane waves with differently coded amplitudes and emission angles in a single transmit event. Data from each single plane wave of increased amplitude can then be obtained, by recombining the received data of successive events with the proper coefficients. The benefits of multiplane wave for B-mode, shear wave elastography and ultrafast Doppler imaging are experimentally demonstrated. Multiplane wave with 4 plane waves emissions yields a 5.8  ±  0.5 dB increase in signal-to-noise ratio and approximately 10 mm in penetration in a calibrated ultrasound phantom (0.7 d MHz(-1) cm(-1)). In shear wave elastography, the same multiplane wave configuration yields a 2.07  ±  0.05 fold reduction of the particle velocity standard deviation and a two-fold reduction of the shear wave velocity maps standard deviation. In functional ultrasound imaging, the mapping of cerebral blood volume results in a 3 to 6 dB increase of the contrast-to-noise ratio in deep

Ultrasound breast imaging using frequency domain reverse time migration

NASA Astrophysics Data System (ADS)

Roy, O.; Zuberi, M. A. H.; Pratt, R. G.; Duric, N.

2016-04-01

Conventional ultrasonography reconstruction techniques, such as B-mode, are based on a simple wave propagation model derived from a high frequency approximation. Therefore, to minimize model mismatch, the central frequency of the input pulse is typically chosen between 3 and 15 megahertz. Despite the increase in theoretical resolution, operating at higher frequencies comes at the cost of lower signal-to-noise ratio. This ultimately degrades the image contrast and overall quality at higher imaging depths. To address this issue, we investigate a reflection imaging technique, known as reverse time migration, which uses a more accurate propagation model for reconstruction. We present preliminary simulation results as well as physical phantom image reconstructions obtained using data acquired with a breast imaging ultrasound tomography prototype. The original reconstructions are filtered to remove low-wavenumber artifacts that arise due to the inclusion of the direct arrivals. We demonstrate the advantage of using an accurate sound speed model in the reverse time migration process. We also explain how the increase in computational complexity can be mitigated using a frequency domain approach and a parallel computing platform.

Monitoring radiofrequency ablation with ultrasound Nakagami imaging.

PubMed

Wang, Chiao-Yin; Geng, Xiaonan; Yeh, Ta-Sen; Liu, Hao-Li; Tsui, Po-Hsiang

2013-07-01

Radiofrequency ablation (RFA) is a widely used alternative modality in the treatment of liver tumors. Ultrasound B-mode imaging is an important tool to guide the insertion of the RFA electrode into the tissue. However, it is difficult to visualize the ablation zone because RFA induces the shadow effect in a B-scan. Based on the randomness of ultrasonic backscattering, this study proposes ultrasound Nakagami imaging, which is a well-established method for backscattered statistics analysis, as an approach to complement the conventional B-scan for evaluating the ablation region. Porcine liver samples (n = 6) were ablated using a RFA system and monitored by employing an ultrasound scanner equipped with a 7.5 MHz linear array transducer. During the stages of ablation (0-12 min) and postablation (12-24 min), the raw backscattered data were acquired at a sampling rate of 30 MHz for B-mode, Nakagami imaging, and polynomial approximation of Nakagami imaging. The contrast-to-noise ratio (CNR) was also calculated to compare the image contrasts of the B-mode and Nakagami images. The results demonstrated that the Nakagami image has the ability to visualize changes in the backscattered statistics in the ablation zone, including the shadow region during RFA. The average Nakagami parameter increased from 0.2 to 0.6 in the ablation stage, and then decreased to approximately 0.3 at the end of the postablation stage. Moreover, the CNR of the Nakagami image was threefold that of the B-mode image, showing that the Nakagami image has a better image contrast for monitoring RFA. Specifically, the use of the polynomial approximation equips the Nakagami image with an enhanced ability to estimate the range of the ablation region. This study demonstrated that ultrasound Nakagami imaging based on the analysis of backscattered statistics has the ability to visualize the RFA-induced ablation zone, even if the shadow effect exists in the B-scan.

Imaging Techniques for Clinical Burn Assessment with a Focus on Multispectral Imaging

PubMed Central

Thatcher, Jeffrey E.; Squiers, John J.; Kanick, Stephen C.; King, Darlene R.; Lu, Yang; Wang, Yulin; Mohan, Rachit; Sellke, Eric W.; DiMaio, J. Michael

2016-01-01

Significance: Burn assessments, including extent and severity, are some of the most critical diagnoses in burn care, and many recently developed imaging techniques may have the potential to improve the accuracy of these evaluations. Recent Advances: Optical devices, telemedicine, and high-frequency ultrasound are among the highlights in recent burn imaging advancements. We present another promising technology, multispectral imaging (MSI), which also has the potential to impact current medical practice in burn care, among a variety of other specialties. Critical Issues: At this time, it is still a matter of debate as to why there is no consensus on the use of technology to assist burn assessments in the United States. Fortunately, the availability of techniques does not appear to be a limitation. However, the selection of appropriate imaging technology to augment the provision of burn care can be difficult for clinicians to navigate. There are many technologies available, but a comprehensive review summarizing the tissue characteristics measured by each technology in light of aiding clinicians in selecting the proper device is missing. This would be especially valuable for the nonburn specialists who encounter burn injuries. Future Directions: The questions of when burn assessment devices are useful to the burn team, how the various imaging devices work, and where the various burn imaging technologies fit into the spectrum of burn care will continue to be addressed. Technologies that can image a large surface area quickly, such as thermography or laser speckle imaging, may be suitable for initial burn assessment and triage. In the setting of presurgical planning, ultrasound or optical microscopy techniques, including optical coherence tomography, may prove useful. MSI, which actually has origins in burn care, may ultimately meet a high number of requirements for burn assessment in routine clinical use. PMID:27602255

Three-dimensional segmentation of luminal and adventitial borders in serial intravascular ultrasound images

NASA Technical Reports Server (NTRS)

Shekhar, R.; Cothren, R. M.; Vince, D. G.; Chandra, S.; Thomas, J. D.; Cornhill, J. F.

1999-01-01

Intravascular ultrasound (IVUS) provides exact anatomy of arteries, allowing accurate quantitative analysis. Automated segmentation of IVUS images is a prerequisite for routine quantitative analyses. We present a new three-dimensional (3D) segmentation technique, called active surface segmentation, which detects luminal and adventitial borders in IVUS pullback examinations of coronary arteries. The technique was validated against expert tracings by computing correlation coefficients (range 0.83-0.97) and William's index values (range 0.37-0.66). The technique was statistically accurate, robust to image artifacts, and capable of segmenting a large number of images rapidly. Active surface segmentation enabled geometrically accurate 3D reconstruction and visualization of coronary arteries and volumetric measurements.

Advanced Ultrasound Technologies for Diagnosis and Therapy.

PubMed

Rix, Anne; Lederle, Wiltrud; Theek, Benjamin; Lammers, Twan; Moonen, Chrit; Schmitz, Georg; Kiessling, Fabian

2018-05-01

Ultrasound is among the most rapidly advancing imaging techniques. Functional methods such as elastography have been clinically introduced, and tissue characterization is improved by contrast-enhanced scans. Here, novel superresolution techniques provide unique morphologic and functional insights into tissue vascularization. Functional analyses are complemented by molecular ultrasound imaging, to visualize markers of inflammation and angiogenesis. The full potential of diagnostic ultrasound may become apparent by integrating these multiple imaging features in radiomics approaches. Emerging interest in ultrasound also results from its therapeutic potential. Various applications of tumor ablation with high-intensity focused ultrasound are being clinically evaluated, and its performance strongly benefits from the integration into MRI. Additionally, oscillating microbubbles mediate sonoporation to open biologic barriers, thus improving the delivery of drugs or nucleic acids that are coadministered or coformulated with microbubbles. This article provides an overview of recent developments in diagnostic and therapeutic ultrasound, highlighting multiple innovation tracks and their translational potential. © 2018 by the Society of Nuclear Medicine and Molecular Imaging.

3D frequency-domain ultrasound waveform tomography breast imaging

NASA Astrophysics Data System (ADS)

Sandhu, Gursharan Yash; West, Erik; Li, Cuiping; Roy, Olivier; Duric, Neb

2017-03-01

Frequency-domain ultrasound waveform tomography is a promising method for the visualization and characterization of breast disease. It has previously been shown to accurately reconstruct the sound speed distributions of breasts of varying densities. The reconstructed images show detailed morphological and quantitative information that can help differentiate different types of breast disease including benign and malignant lesions. The attenuation properties of an ex vivo phantom have also been assessed. However, the reconstruction algorithms assumed a 2D geometry while the actual data acquisition process was not. Although clinically useful sound speed images can be reconstructed assuming this mismatched geometry, artifacts from the reconstruction process exist within the reconstructed images. This is especially true for registration across different modalities and when the 2D assumption is violated. For example, this happens when a patient's breast is rapidly sloping. It is also true for attenuation imaging where energy lost or gained out of the plane gets transformed into artifacts within the image space. In this paper, we will briefly review ultrasound waveform tomography techniques, give motivation for pursuing the 3D method, discuss the 3D reconstruction algorithm, present the results of 3D forward modeling, show the mismatch that is induced by the violation of 3D modeling via numerical simulations, and present a 3D inversion of a numerical phantom.

Ultrasound-Guided Intervention for Treatment of Trigeminal Neuralgia: An Updated Review of Anatomy and Techniques

PubMed Central

Allam, Abdallah El-Sayed; Khalil, Adham Aboul Fotouh; Eltawab, Basma Aly; Wu, Wei-Ting

2018-01-01

Orofacial myofascial pain is prevalent and most often results from entrapment of branches of the trigeminal nerves. It is challenging to inject branches of the trigeminal nerve, a large portion of which are shielded by the facial bones. Bony landmarks of the cranium serve as important guides for palpation-guided injections and can be delineated using ultrasound. Ultrasound also provides real-time images of the adjacent muscles and accompanying arteries and can be used to guide the needle to the target region. Most importantly, ultrasound guidance significantly reduces the risk of collateral injury to vital neurovascular structures. In this review, we aimed to summarize the regional anatomy and ultrasound-guided injection techniques for the trigeminal nerve and its branches, including the supraorbital, infraorbital, mental, auriculotemporal, maxillary, and mandibular nerves. PMID:29808105

Ultrasound in Radiology: from Anatomic, Functional, Molecular Imaging to Drug Delivery and Image-Guided Therapy

PubMed Central

Klibanov, Alexander L.; Hossack, John A.

2015-01-01

During the past decade, ultrasound has expanded medical imaging well beyond the “traditional” radiology setting - a combination of portability, low cost and ease of use makes ultrasound imaging an indispensable tool for radiologists as well as for other medical professionals who need to obtain imaging diagnosis or guide a therapeutic intervention quickly and efficiently. Ultrasound combines excellent ability for deep penetration into soft tissues with very good spatial resolution, with only a few exceptions (i.e. those involving overlying bone or gas). Real-time imaging (up to hundreds and thousands frames per second) enables guidance of therapeutic procedures and biopsies; characterization of the mechanical properties of the tissues greatly aids with the accuracy of the procedures. The ability of ultrasound to deposit energy locally brings about the potential for localized intervention encompassing: tissue ablation, enhancing penetration through the natural barriers to drug delivery in the body and triggering drug release from carrier micro- and nanoparticles. The use of microbubble contrast agents brings the ability to monitor and quantify tissue perfusion, and microbubble targeting with ligand-decorated microbubbles brings the ability to obtain molecular biomarker information, i.e., ultrasound molecular imaging. Overall, ultrasound has become the most widely used imaging modality in modern medicine; it will continue to grow and expand. PMID:26200224

Quantitative contrast-enhanced ultrasound imaging: a review of sources of variability

PubMed Central

Tang, M.-X.; Mulvana, H.; Gauthier, T.; Lim, A. K. P.; Cosgrove, D. O.; Eckersley, R. J.; Stride, E.

2011-01-01

Ultrasound provides a valuable tool for medical diagnosis offering real-time imaging with excellent spatial resolution and low cost. The advent of microbubble contrast agents has provided the additional ability to obtain essential quantitative information relating to tissue vascularity, tissue perfusion and even endothelial wall function. This technique has shown great promise for diagnosis and monitoring in a wide range of clinical conditions such as cardiovascular diseases and cancer, with considerable potential benefits in terms of patient care. A key challenge of this technique, however, is the existence of significant variations in the imaging results, and the lack of understanding regarding their origin. The aim of this paper is to review the potential sources of variability in the quantification of tissue perfusion based on microbubble contrast-enhanced ultrasound images. These are divided into the following three categories: (i) factors relating to the scanner setting, which include transmission power, transmission focal depth, dynamic range, signal gain and transmission frequency, (ii) factors relating to the patient, which include body physical differences, physiological interaction of body with bubbles, propagation and attenuation through tissue, and tissue motion, and (iii) factors relating to the microbubbles, which include the type of bubbles and their stability, preparation and injection and dosage. It has been shown that the factors in all the three categories can significantly affect the imaging results and contribute to the variations observed. How these factors influence quantitative imaging is explained and possible methods for reducing such variations are discussed. PMID:22866229

Development of ultrasound transducer diffractive field theory for nonlinear propagation-based imaging

NASA Astrophysics Data System (ADS)

Kharin, Nikolay A.

2000-04-01

In nonlinear ultrasound imaging the images are formed using the second harmonic energy generated due to the nonlinear nature of finite amplitude propagation. This propagation can be modeled using the KZK wave equation. This paper presents further development of nonlinear diffractive field theory based on the KZK equation and its solution by means of the slowly changing profile method for moderate nonlinearity. The analytical expression for amplitudes and phases of sum frequency wave are obtained in addition to the second harmonic wave. Also, the analytical expression for the relative curvature of the wave fronts of fundamental and second harmonic signals are derived. The media with different nonlinear properties and absorption coefficients were investigated to characterize the diffractive field of the transducer at medical frequencies. All expressions demonstrate good agreement with experimental results. The expressions are novel and provide an easy way for prediction of amplitude and phase structure of nonlinearly distorted field of a transducer. The sum frequency signal technique could be implemented as well as second harmonic technique to improve the quality of biomedical images. The results obtained are of importance for medical diagnostic ultrasound equipment design.

Light and sound - emerging imaging techniques for inflammatory bowel disease

PubMed Central

Knieling, Ferdinand; Waldner, Maximilian J

2016-01-01

Patients with inflammatory bowel disease are known to have a high demand of recurrent evaluation for therapy and disease activity. Further, the risk of developing cancer during the disease progression is increasing from year to year. New, mostly non-radiant, quick to perform and quantitative methods are challenging, conventional endoscopy with biopsy as gold standard. Especially, new physical imaging approaches utilizing light and sound waves have facilitated the development of advanced functional and molecular modalities. Besides these advantages they hold the promise to predict personalized therapeutic responses and to spare frequent invasive procedures. Within this article we highlight their potential for initial diagnosis, assessment of disease activity and surveillance of cancer development in established techniques and recent advances such as wide-view full-spectrum endoscopy, chromoendoscopy, autofluorescence endoscopy, endocytoscopy, confocal laser endoscopy, multiphoton endoscopy, molecular imaging endoscopy, B-mode and Doppler ultrasound, contrast-enhanced ultrasound, ultrasound molecular imaging, and elastography. PMID:27433080

Imaging nonmelanoma skin cancers with combined ultrasound-photoacoustic microscopy

NASA Astrophysics Data System (ADS)

Sunar, Ulas; Rohrbach, Daniel J.; Morgan, Janet; Zeitouni, Natalie

2013-03-01

PDT has become a treatment of choice especially for the cases with multiple sites and large areas. However, the efficacy of PDT is limited for thicker and deeper tumors. Depth and size information as well as vascularity can provide useful information to clinicians for planning and evaluating PDT. High-resolution ultrasound and photoacoustic imaging can provide information regarding skin structure and vascularity. We utilized combined ultrasound-photoacoustic microscopy for imaging a basal cell carcinoma (BCC) tumor pre-PDT and the results indicate that combined ultrasound-photoacoustic imaging can be useful tool for PDT planning by providing both structural and functional contrasts.

Bedside imaging of intracranial hemorrhage in the neonate using light: comparison with ultrasound, computed tomography, and magnetic resonance imaging.

PubMed

Hintz, S R; Cheong, W F; van Houten, J P; Stevenson, D K; Benaron, D A

1999-01-01

Medical optical imaging (MOI) uses light emitted into opaque tissues to determine the interior structure. Previous reports detailed a portable time-of-flight and absorbance system emitting pulses of near infrared light into tissues and measuring the emerging light. Using this system, optical images of phantoms, whole rats, and pathologic neonatal brain specimens have been tomographically reconstructed. We have now modified the existing instrumentation into a clinically relevant headband-based system to be used for optical imaging of structure in the neonatal brain at the bedside. Eight medical optical imaging studies in the neonatal intensive care unit were performed in a blinded clinical comparison of optical images with ultrasound, computed tomography, and magnetic resonance imaging. Optical images were interpreted as correct in six of eight cases, with one error attributed to the age of the clot, and one small clot not seen. In addition, one disagreement with ultrasound, not reported as an error, was found to be the result of a mislabeled ultrasound report rather than because of an inaccurate optical scan. Optical scan correlated well with computed tomography and magnetic resonance imaging findings in one patient. We conclude that light-based imaging using a portable time-of-flight system is feasible and represents an important new noninvasive diagnostic technique, with potential for continuous monitoring of critically ill neonates at risk for intraventricular hemorrhage or stroke. Further studies are now underway to further investigate the functional imaging capabilities of this new diagnostic tool.

Ultrasound coefficient of nonlinearity imaging.

PubMed

van Sloun, Ruud; Demi, Libertario; Shan, Caifeng; Mischi, Massimo

2015-07-01

Imaging the acoustical coefficient of nonlinearity, β, is of interest in several healthcare interventional applications. It is an important feature that can be used for discriminating tissues. In this paper, we propose a nonlinearity characterization method with the goal of locally estimating the coefficient of nonlinearity. The proposed method is based on a 1-D solution of the nonlinear lossy Westerfelt equation, thereby deriving a local relation between β and the pressure wave field. Based on several assumptions, a β imaging method is then presented that is based on the ratio between the harmonic and fundamental fields, thereby reducing the effect of spatial amplitude variations of the speckle pattern. By testing the method on simulated ultrasound pressure fields and an in vitro B-mode ultrasound acquisition, we show that the designed algorithm is able to estimate the coefficient of nonlinearity, and that the tissue types of interest are well discriminable. The proposed imaging method provides a new approach to β estimation, not requiring a special measurement setup or transducer, that seems particularly promising for in vivo imaging.

Micro-ultrasound for preclinical imaging

PubMed Central

Foster, F. Stuart; Hossack, John; Adamson, S. Lee

2011-01-01

Over the past decade, non-invasive preclinical imaging has emerged as an important tool to facilitate biomedical discovery. Not only have the markets for these tools accelerated, but the numbers of peer-reviewed papers in which imaging end points and biomarkers have been used have grown dramatically. High frequency ‘micro-ultrasound’ has steadily evolved in the post-genomic era as a rapid, comparatively inexpensive imaging tool for studying normal development and models of human disease in small animals. One of the fundamental barriers to this development was the technological hurdle associated with high-frequency array transducers. Recently, new approaches have enabled the upper limits of linear and phased arrays to be pushed from about 20 to over 50 MHz enabling a broad range of new applications. The innovations leading to the new transducer technology and scanner architecture are reviewed. Applications of preclinical micro-ultrasound are explored for developmental biology, cancer, and cardiovascular disease. With respect to the future, the latest developments in high-frequency ultrasound imaging are described. PMID:22866232

Geometric reconstruction using tracked ultrasound strain imaging

NASA Astrophysics Data System (ADS)

Pheiffer, Thomas S.; Simpson, Amber L.; Ondrake, Janet E.; Miga, Michael I.

2013-03-01

The accurate identification of tumor margins during neurosurgery is a primary concern for the surgeon in order to maximize resection of malignant tissue while preserving normal function. The use of preoperative imaging for guidance is standard of care, but tumor margins are not always clear even when contrast agents are used, and so margins are often determined intraoperatively by visual and tactile feedback. Ultrasound strain imaging creates a quantitative representation of tissue stiffness which can be used in real-time. The information offered by strain imaging can be placed within a conventional image-guidance workflow by tracking the ultrasound probe and calibrating the image plane, which facilitates interpretation of the data by placing it within a common coordinate space with preoperative imaging. Tumor geometry in strain imaging is then directly comparable to the geometry in preoperative imaging. This paper presents a tracked ultrasound strain imaging system capable of co-registering with preoperative tomograms and also of reconstructing a 3D surface using the border of the strain lesion. In a preliminary study using four phantoms with subsurface tumors, tracked strain imaging was registered to preoperative image volumes and then tumor surfaces were reconstructed using contours extracted from strain image slices. The volumes of the phantom tumors reconstructed from tracked strain imaging were approximately between 1.5 to 2.4 cm3, which was similar to the CT volumes of 1.0 to 2.3 cm3. Future work will be done to robustly characterize the reconstruction accuracy of the system.

Opto-acoustic breast imaging with co-registered ultrasound

NASA Astrophysics Data System (ADS)

Zalev, Jason; Clingman, Bryan; Herzog, Don; Miller, Tom; Stavros, A. Thomas; Oraevsky, Alexander; Kist, Kenneth; Dornbluth, N. Carol; Otto, Pamela

2014-03-01

We present results from a recent study involving the ImagioTM breast imaging system, which produces fused real-time two-dimensional color-coded opto-acoustic (OA) images that are co-registered and temporally inter- leaved with real-time gray scale ultrasound using a specialized duplex handheld probe. The use of dual optical wavelengths provides functional blood map images of breast tissue and tumors displayed with high contrast based on total hemoglobin and oxygen saturation of the blood. This provides functional diagnostic information pertaining to tumor metabolism. OA also shows morphologic information about tumor neo-vascularity that is complementary to the morphological information obtained with conventional gray scale ultrasound. This fusion technology conveniently enables real-time analysis of the functional opto-acoustic features of lesions detected by readers familiar with anatomical gray scale ultrasound. We demonstrate co-registered opto-acoustic and ultrasonic images of malignant and benign tumors from a recent clinical study that provide new insight into the function of tumors in-vivo. Results from the Feasibility Study show preliminary evidence that the technology may have the capability to improve characterization of benign and malignant breast masses over conventional diagnostic breast ultrasound alone and to improve overall accuracy of breast mass diagnosis. In particular, OA improved speci city over that of conventional diagnostic ultrasound, which could potentially reduce the number of negative biopsies performed without missing cancers.

Ultrasonic Imaging Techniques for Breast Cancer Detection

NASA Astrophysics Data System (ADS)

Goulding, N. R.; Marquez, J. D.; Prewett, E. M.; Claytor, T. N.; Nadler, B. R.

2008-02-01

Improving the resolution and specificity of current ultrasonic imaging technology is needed to enhance its relevance to breast cancer detection. A novel ultrasonic imaging reconstruction method is described that exploits classical straight-ray migration. This novel method improves signal processing for better image resolution and uses novel staging hardware options using a pulse-echo approach. A breast phantom with various inclusions is imaged using the classical migration method and is compared to standard computed tomography (CT) scans. These innovative ultrasonic methods incorporate ultrasound data acquisition, beam profile characterization, and image reconstruction. For an ultrasonic frequency of 2.25 MHz, imaged inclusions of approximately 1 cm are resolved and identified. Better resolution is expected with minor modifications. Improved image quality and resolution enables earlier detection and more accurate diagnoses of tumors thus reducing the number of biopsies performed, increasing treatment options, and lowering remission percentages. Using these new techniques the inclusions in the phantom are resolved and compared to the results of standard methods. Refinement of this application using other imaging techniques such as time-reversal mirrors (TRM), synthetic aperture focusing technique (SAFT), decomposition of the time reversal operator (DORT), and factorization methods is also discussed.

Ultrasound window-modulated compounding Nakagami imaging: Resolution improvement and computational acceleration for liver characterization.

PubMed

Ma, Hsiang-Yang; Lin, Ying-Hsiu; Wang, Chiao-Yin; Chen, Chiung-Nien; Ho, Ming-Chih; Tsui, Po-Hsiang

2016-08-01

Ultrasound Nakagami imaging is an attractive method for visualizing changes in envelope statistics. Window-modulated compounding (WMC) Nakagami imaging was reported to improve image smoothness. The sliding window technique is typically used for constructing ultrasound parametric and Nakagami images. Using a large window overlap ratio may improve the WMC Nakagami image resolution but reduces computational efficiency. Therefore, the objectives of this study include: (i) exploring the effects of the window overlap ratio on the resolution and smoothness of WMC Nakagami images; (ii) proposing a fast algorithm that is based on the convolution operator (FACO) to accelerate WMC Nakagami imaging. Computer simulations and preliminary clinical tests on liver fibrosis samples (n=48) were performed to validate the FACO-based WMC Nakagami imaging. The results demonstrated that the width of the autocorrelation function and the parameter distribution of the WMC Nakagami image reduce with the increase in the window overlap ratio. One-pixel shifting (i.e., sliding the window on the image data in steps of one pixel for parametric imaging) as the maximum overlap ratio significantly improves the WMC Nakagami image quality. Concurrently, the proposed FACO method combined with a computational platform that optimizes the matrix computation can accelerate WMC Nakagami imaging, allowing the detection of liver fibrosis-induced changes in envelope statistics. FACO-accelerated WMC Nakagami imaging is a new-generation Nakagami imaging technique with an improved image quality and fast computation. Copyright © 2016 Elsevier B.V. All rights reserved.

Programmable Real-time Clinical Photoacoustic and Ultrasound Imaging System

PubMed Central

Kim, Jeesu; Park, Sara; Jung, Yuhan; Chang, Sunyeob; Park, Jinyong; Zhang, Yumiao; Lovell, Jonathan F.; Kim, Chulhong

2016-01-01

Photoacoustic imaging has attracted interest for its capacity to capture functional spectral information with high spatial and temporal resolution in biological tissues. Several photoacoustic imaging systems have been commercialized recently, but they are variously limited by non-clinically relevant designs, immobility, single anatomical utility (e.g., breast only), or non-programmable interfaces. Here, we present a real-time clinical photoacoustic and ultrasound imaging system which consists of an FDA-approved clinical ultrasound system integrated with a portable laser. The system is completely programmable, has an intuitive user interface, and can be adapted for different applications by switching handheld imaging probes with various transducer types. The customizable photoacoustic and ultrasound imaging system is intended to meet the diverse needs of medical researchers performing both clinical and preclinical photoacoustic studies. PMID:27731357

Programmable Real-time Clinical Photoacoustic and Ultrasound Imaging System.

PubMed

Kim, Jeesu; Park, Sara; Jung, Yuhan; Chang, Sunyeob; Park, Jinyong; Zhang, Yumiao; Lovell, Jonathan F; Kim, Chulhong

2016-10-12

Photoacoustic imaging has attracted interest for its capacity to capture functional spectral information with high spatial and temporal resolution in biological tissues. Several photoacoustic imaging systems have been commercialized recently, but they are variously limited by non-clinically relevant designs, immobility, single anatomical utility (e.g., breast only), or non-programmable interfaces. Here, we present a real-time clinical photoacoustic and ultrasound imaging system which consists of an FDA-approved clinical ultrasound system integrated with a portable laser. The system is completely programmable, has an intuitive user interface, and can be adapted for different applications by switching handheld imaging probes with various transducer types. The customizable photoacoustic and ultrasound imaging system is intended to meet the diverse needs of medical researchers performing both clinical and preclinical photoacoustic studies.

Standardized ultrasound templates for diagnosing appendicitis reduce annual imaging costs.

PubMed

Nordin, Andrew B; Sales, Stephen; Nielsen, Jason W; Adler, Brent; Bates, David Gregory; Kenney, Brian

2018-01-01

Ultrasound is preferred over computed tomography (CT) for diagnosing appendicitis in children to avoid undue radiation exposure. We previously reported our experience in instituting a standardized appendicitis ultrasound template, which decreased CT rates by 67.3%. In this analysis, we demonstrate the ongoing cost savings associated with using this template. Retrospective chart review for the time period preceding template implementation (June 2012-September 2012) was combined with prospective review through December 2015 for all patients in the emergency department receiving diagnostic imaging for appendicitis. The type of imaging was recorded, and imaging rates and ultrasound test statistics were calculated. Estimated annual imaging costs based on pretemplate ultrasound and CT utilization rates were compared with post-template annual costs to calculate annual and cumulative savings. In the pretemplate period, ultrasound and CT rates were 80.2% and 44.3%, respectively, resulting in a combined annual cost of $300,527.70. Similar calculations were performed for each succeeding year, accounting for changes in patient volume. Using pretemplate rates, our projected 2015 imaging cost was $371,402.86; however, our ultrasound rate had increased to 98.3%, whereas the CT rate declined to 9.6%, yielding an annual estimated cost of $224,853.00 and a savings of $146,549.86. Since implementation, annual savings have steadily increased for a cumulative cost savings of $336,683.83. Standardizing ultrasound reports for appendicitis not only reduces the use of CT scans and the associated radiation exposure but also decreases annual imaging costs despite increased numbers of imaging studies. Continued cost reduction may be possible by using diagnostic algorithms. Copyright © 2017 Elsevier Inc. All rights reserved.

Experience With Intravascular Ultrasound Imaging Of Human Atherosclerotic Arteries

NASA Astrophysics Data System (ADS)

Mallery, John A.; Gessert, James M.; Maciel, Mario; Tobis, John M.; Griffith, James M.; Berns, Michael W.; Henry, Walter L.

1989-08-01

Normal human arteries have a well-defined structure on intravascular images. The intima appears very thin and is most likely represented by a bright reflection arising from the internal elastic lamina. The smooth muscle tunica media is echo-lucent on the ultrasound image and appears as a dark band separating the intima from the adventitia. The adventitia is a brightly reflective layer of variable thickness. The thickness of the intima, and therefore of the atherosclerotic plaque can be accurately measured from the ultrasound images and correlates well with histology. Calcification within the wall of arteries is seen as bright echo reflection with shadowing of the peripheral wall. Fibrotic regions are highly reflective but do not shadow. Necrotic liquid regions within advanced atherosclerotic plaques are seen on ultrasound images as large lucent zones surrounded by echogenic tissue. Imaging can be performed before and after interventional procedures, such as laser angioplasty, balloon angioplasty and atherectomy. Intravascular ultrasound appears to provide an imaging modality for identifying the histologic characteristics of diseased arteries and for quantifying plaque thickness. It might be possible to perform such quantification to evaluate the results of interventional procedures.

Diaphragm breathing movement measurement using ultrasound and radiographic imaging: a concurrent validity.

PubMed

Noh, Dong K; Lee, Jae J; You, Joshua H

2014-01-01

Recent ultrasound imaging evidence asserts that the diaphragm is an important multifunctional muscle to control breathing as well as stabilize the core and posture in humans. However, the validity and accuracy of ultrasound for the measurement of dynamic diaphragm movements during breathing and functional core activities have not been determined. The specific aim of this study was to validate the accuracy of ultrasound imaging measurements of diaphragm movements by concurrently comparing these measurements to the gold standard of radiographic imaging measurements. A total of 14 asymptomatic adults (9 males, 5 females; mean age =28.4 ± 3.0 years) were recruited to participate in the study. Ultrasound and radiographic images were used concurrently to determine diaphragm movement (inspiration, expiration, and excursion) during tidal breathing. Pearson correlation analysis showed strong correlations, ranging from r=0.78 to r=0.83, between ultrasound and radiographic imaging measurements of the diaphragm during inhalation, exhalation, and excursion. These findings suggest that ultrasound imaging measurement is useful to accurately evaluate diaphragm movements during tidal breathing. Clinically, ultrasound imaging measurements can be used to diagnose and treat diaphragm movement impairments in individuals with neuromuscular disorders including spinal cord injuries, stroke, and multiple sclerosis.

Small-window parametric imaging based on information entropy for ultrasound tissue characterization

PubMed Central

Tsui, Po-Hsiang; Chen, Chin-Kuo; Kuo, Wen-Hung; Chang, King-Jen; Fang, Jui; Ma, Hsiang-Yang; Chou, Dean

2017-01-01

Constructing ultrasound statistical parametric images by using a sliding window is a widely adopted strategy for characterizing tissues. Deficiency in spatial resolution, the appearance of boundary artifacts, and the prerequisite data distribution limit the practicability of statistical parametric imaging. In this study, small-window entropy parametric imaging was proposed to overcome the above problems. Simulations and measurements of phantoms were executed to acquire backscattered radiofrequency (RF) signals, which were processed to explore the feasibility of small-window entropy imaging in detecting scatterer properties. To validate the ability of entropy imaging in tissue characterization, measurements of benign and malignant breast tumors were conducted (n = 63) to compare performances of conventional statistical parametric (based on Nakagami distribution) and entropy imaging by the receiver operating characteristic (ROC) curve analysis. The simulation and phantom results revealed that entropy images constructed using a small sliding window (side length = 1 pulse length) adequately describe changes in scatterer properties. The area under the ROC for using small-window entropy imaging to classify tumors was 0.89, which was higher than 0.79 obtained using statistical parametric imaging. In particular, boundary artifacts were largely suppressed in the proposed imaging technique. Entropy enables using a small window for implementing ultrasound parametric imaging. PMID:28106118

Small-window parametric imaging based on information entropy for ultrasound tissue characterization

NASA Astrophysics Data System (ADS)

Tsui, Po-Hsiang; Chen, Chin-Kuo; Kuo, Wen-Hung; Chang, King-Jen; Fang, Jui; Ma, Hsiang-Yang; Chou, Dean

2017-01-01

Constructing ultrasound statistical parametric images by using a sliding window is a widely adopted strategy for characterizing tissues. Deficiency in spatial resolution, the appearance of boundary artifacts, and the prerequisite data distribution limit the practicability of statistical parametric imaging. In this study, small-window entropy parametric imaging was proposed to overcome the above problems. Simulations and measurements of phantoms were executed to acquire backscattered radiofrequency (RF) signals, which were processed to explore the feasibility of small-window entropy imaging in detecting scatterer properties. To validate the ability of entropy imaging in tissue characterization, measurements of benign and malignant breast tumors were conducted (n = 63) to compare performances of conventional statistical parametric (based on Nakagami distribution) and entropy imaging by the receiver operating characteristic (ROC) curve analysis. The simulation and phantom results revealed that entropy images constructed using a small sliding window (side length = 1 pulse length) adequately describe changes in scatterer properties. The area under the ROC for using small-window entropy imaging to classify tumors was 0.89, which was higher than 0.79 obtained using statistical parametric imaging. In particular, boundary artifacts were largely suppressed in the proposed imaging technique. Entropy enables using a small window for implementing ultrasound parametric imaging.

Dual-Modality PET/Ultrasound imaging of the Prostate

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

Huber, Jennifer S.; Moses, William W.; Pouliot, Jean

2005-11-11

Functional imaging with positron emission tomography (PET)will detect malignant tumors in the prostate and/or prostate bed, as well as possibly help determine tumor ''aggressiveness''. However, the relative uptake in a prostate tumor can be so great that few other anatomical landmarks are visible in a PET image. Ultrasound imaging with a transrectal probe provides anatomical detail in the prostate region that can be co-registered with the sensitive functional information from the PET imaging. Imaging the prostate with both PET and transrectal ultrasound (TRUS) will help determine the location of any cancer within the prostate region. This dual-modality imaging should helpmore » provide better detection and treatment of prostate cancer. LBNL has built a high performance positron emission tomograph optimized to image the prostate.Compared to a standard whole-body PET camera, our prostate-optimized PET camera has the same sensitivity and resolution, less backgrounds and lower cost. We plan to develop the hardware and software tools needed for a validated dual PET/TRUS prostate imaging system. We also plan to develop dual prostate imaging with PET and external transabdominal ultrasound, in case the TRUS system is too uncomfortable for some patients. We present the design and intended clinical uses for these dual imaging systems.« less

Multispectral photoacoustic imaging of nerves with a clinical ultrasound system

NASA Astrophysics Data System (ADS)

Mari, Jean Martial; West, Simeon; Beard, Paul C.; Desjardins, Adrien E.

2014-03-01

Accurate and efficient identification of nerves is of great importance during many ultrasound-guided clinical procedures, including nerve blocks and prostate biopsies. It can be challenging to visualise nerves with conventional ultrasound imaging, however. One of the challenges is that nerves can have very similar appearances to nearby structures such as tendons. Several recent studies have highlighted the potential of near-infrared optical spectroscopy for differentiating nerves and adjacent tissues, as this modality can be sensitive to optical absorption of lipids that are present in intra- and extra-neural adipose tissue and in the myelin sheaths. These studies were limited to point measurements, however. In this pilot study, a custom photoacoustic system with a clinical ultrasound imaging probe was used to acquire multi-spectral photoacoustic images of nerves and tendons from swine ex vivo, across the wavelength range of 1100 to 1300 nm. Photoacoustic images were processed and overlaid in colour onto co-registered conventional ultrasound images that were acquired with the same imaging probe. A pronounced optical absorption peak centred at 1210 nm was observed in the photoacoustic signals obtained from nerves, and it was absent in those obtained from tendons. This absorption peak, which is consistent with the presence of lipids, provides a novel image contrast mechanism to significantly enhance the visualization of nerves. In particular, image contrast for nerves was up to 5.5 times greater with photoacoustic imaging (0.82 +/- 0.15) than with conventional ultrasound imaging (0.148 +/- 0.002), with a maximum contrast of 0.95 +/- 0.02 obtained in photoacoustic mode. This pilot study demonstrates the potential of photoacoustic imaging to improve clinical outcomes in ultrasound-guided interventions in regional anaesthesia and interventional oncology.

Watermarking of ultrasound medical images in teleradiology using compressed watermark

PubMed Central

Badshah, Gran; Liew, Siau-Chuin; Zain, Jasni Mohamad; Ali, Mushtaq

2016-01-01

Abstract. The open accessibility of Internet-based medical images in teleradialogy face security threats due to the nonsecured communication media. This paper discusses the spatial domain watermarking of ultrasound medical images for content authentication, tamper detection, and lossless recovery. For this purpose, the image is divided into two main parts, the region of interest (ROI) and region of noninterest (RONI). The defined ROI and its hash value are combined as watermark, lossless compressed, and embedded into the RONI part of images at pixel’s least significant bits (LSBs). The watermark lossless compression and embedding at pixel’s LSBs preserve image diagnostic and perceptual qualities. Different lossless compression techniques including Lempel-Ziv-Welch (LZW) were tested for watermark compression. The performances of these techniques were compared based on more bit reduction and compression ratio. LZW was found better than others and used in tamper detection and recovery watermarking of medical images (TDARWMI) scheme development to be used for ROI authentication, tamper detection, localization, and lossless recovery. TDARWMI performance was compared and found to be better than other watermarking schemes. PMID:26839914

Fiber-Laser-Based Ultrasound Sensor for Photoacoustic Imaging

PubMed Central

Liang, Yizhi; Jin, Long; Wang, Lidai; Bai, Xue; Cheng, Linghao; Guan, Bai-Ou

2017-01-01

Photoacoustic imaging, especially for intravascular and endoscopic applications, requires ultrasound probes with miniature size and high sensitivity. In this paper, we present a new photoacoustic sensor based on a small-sized fiber laser. Incident ultrasound waves exert pressures on the optical fiber laser and induce harmonic vibrations of the fiber, which is detected by the frequency shift of the beating signal between the two orthogonal polarization modes in the fiber laser. This ultrasound sensor presents a noise-equivalent pressure of 40 Pa over a 50-MHz bandwidth. We demonstrate this new ultrasound sensor on an optical-resolution photoacoustic microscope. The axial and lateral resolutions are 48 μm and 3.3 μm. The field of view is up to 1.57 mm2. The sensor exhibits strong resistance to environmental perturbations, such as temperature changes, due to common-mode cancellation between the two orthogonal modes. The present fiber laser ultrasound sensor offers a new tool for all-optical photoacoustic imaging. PMID:28098201

Composite ultrasound imaging apparatus and method

DOEpatents

Morimoto, Alan K.; Bow, Jr., Wallace J.; Strong, David Scott; Dickey, Fred M.

1998-01-01

An imaging apparatus and method for use in presenting composite two dimensional and three dimensional images from individual ultrasonic frames. A cross-sectional reconstruction is applied by using digital ultrasound frames, transducer orientation and a known center. Motion compensation, rank value filtering, noise suppression and tissue classification are utilized to optimize the composite image.

Imaging of Groin Pain: Magnetic Resonance and Ultrasound Imaging Features.

PubMed

Lee, Susan C; Endo, Yoshimi; Potter, Hollis G

Evaluation of groin pain in athletes may be challenging as pain is typically poorly localized and the pubic symphyseal region comprises closely approximated tendons and muscles. As such, magnetic resonance imaging (MRI) and ultrasound (US) may help determine the etiology of groin pain. A PubMed search was performed using the following search terms: ultrasound, magnetic resonance imaging, sports hernia, athletic pubalgia, and groin pain. Date restrictions were not placed on the literature search. Clinical review. Level 4. MRI is sensitive in diagnosing pathology in groin pain. Not only can MRI be used to image rectus abdominis/adductor longus aponeurosis and pubic bone pathology, but it can also evaluate other pathology within the hip and pelvis. MRI is especially helpful when groin pain is poorly localized. Real-time capability makes ultrasound useful in evaluating the pubic symphyseal region, as it can be used for evaluation and treatment. MRI and US are valuable in diagnosing pathology in athletes with groin pain, with the added utility of treatment using US-guided intervention. Strength-of Recommendation Taxonomy: C.

High-resolution ultrasound imaging and noninvasive optoacoustic monitoring of blood variables in peripheral blood vessels

NASA Astrophysics Data System (ADS)

Petrov, Irene Y.; Petrov, Yuriy; Prough, Donald S.; Esenaliev, Rinat O.

2011-03-01

Ultrasound imaging is being widely used in clinics to obtain diagnostic information non-invasively and in real time. A high-resolution ultrasound imaging platform, Vevo (VisualSonics, Inc.) provides in vivo, real-time images with exceptional resolution (up to 30 microns) using high-frequency transducers (up to 80 MHz). Recently, we built optoacoustic systems for probing radial artery and peripheral veins that can be used for noninvasive monitoring of total hemoglobin concentration, oxyhemoglobin saturation, and concentration of important endogenous and exogenous chromophores (such as ICG). In this work we used the high-resolution ultrasound imaging system Vevo 770 for visualization of the radial artery and peripheral veins and acquired corresponding optoacoustic signals from them using the optoacoustic systems. Analysis of the optoacoustic data with a specially developed algorithm allowed for measurement of blood oxygenation in the blood vessels as well as for continuous, real-time monitoring of arterial and venous blood oxygenation. Our results indicate that: 1) the optoacoustic technique (unlike pure optical approaches and other noninvasive techniques) is capable of accurate peripheral venous oxygenation measurement; and 2) peripheral venous oxygenation is dependent on skin temperature and local hemodynamics. Moreover, we performed for the first time (to the best of our knowledge) a comparative study of optoacoustic arterial oximetry and a standard pulse oximeter in humans and demonstrated superior performance of the optoacoustic arterial oximeter, in particular at low blood flow.

Benefits of Ultrasound Imaging for Placement of Caudal Epidural Blockade in 3 Pediatric Patients: A Case Report.

PubMed

Sinskey, Jina L; Vecchione, Tricia M; Ekstrom, Benjamin G; Boretsky, Karen

2018-06-01

Pediatric caudal epidural blockade, the most common pediatric regional anesthetic, is classically placed using surface landmark technique with infrequent use of ultrasound guidance. We present 3 cases where ultrasound guidance facilitated successful placement and helped prevent complications. One infant had an unanticipated S5 dural sac necessitating needle redirection to avoid subarachnoid injection. A 5-year old had proper needle position with inability to inject secondary to needle blockage confirmed with ultrasound. An expremature infant had initial needle placement anterior to the sacrum with subsequent proper placement using real-time ultrasound imaging. Ultrasound guidance for pediatric caudal placement confers advantages and increased routine use should be considered.

Composite ultrasound imaging apparatus and method

DOEpatents

Morimoto, A.K.; Bow, W.J. Jr.; Strong, D.S.; Dickey, F.M.

1998-09-15

An imaging apparatus and method for use in presenting composite two dimensional and three dimensional images from individual ultrasonic frames. A cross-sectional reconstruction is applied by using digital ultrasound frames, transducer orientation and a known center. Motion compensation, rank value filtering, noise suppression and tissue classification are utilized to optimize the composite image. 37 figs.

Variogram methods for texture classification of atherosclerotic plaque ultrasound images

NASA Astrophysics Data System (ADS)

Jeromin, Oliver M.; Pattichis, Marios S.; Pattichis, Constantinos; Kyriacou, Efthyvoulos; Nicolaides, Andrew

2006-03-01

Stroke is the third leading cause of death in the western world and the major cause of disability in adults. The type and stenosis of extracranial carotid artery disease is often responsible for ischemic strokes, transient ischemic attacks (TIAs) or amaurosis fugax (AF). The identification and grading of stenosis can be done using gray scale ultrasound scans. The appearance of B-scan pictures containing various granular structures makes the use of texture analysis techniques suitable for computer assisted tissue characterization purposes. The objective of this study is to investigate the usefulness of variogram analysis in the assessment of ultrasound plague morphology. The variogram estimates the variance of random fields, from arbitrary samples in space. We explore stationary random field models based on the variogram, which can be applied in ultrasound plaque imaging leading to a Computer Aided Diagnosis (CAD) system for the early detection of symptomatic atherosclerotic plaques. Non-parametric tests on the variogram coefficients show that the cofficients coming from symptomatic versus asymptomatic plaques come from distinct distributions. Furthermore, we show significant improvement in class separation, when a log point-transformation is applied to the images, prior to variogram estimation. Model fitting using least squares is explored for anisotropic variograms along specific directions. Comparative classification results, show that variogram coefficients can be used for the early detection of symptomatic cases, and also exhibit the largest class distances between symptomatic and asymptomatic plaque images, as compared to over 60 other texture features, used in the literature.

Bowel Thickening in Crohn's Disease: Fibrosis or Inflammation? Diagnostic Ultrasound Imaging Tools.

PubMed

Coelho, Rosa; Ribeiro, Helena; Maconi, Giovanni

2017-01-01

The high frequency of intestinal strictures in patients with Crohn's disease and the different treatment approaches specific for each type of stenosis make the differentiation between fibrotic and inflammatory strictures crucial in management of the disease. However, there is no standardized approach to evaluate and discriminate intestinal strictures, and until now, there was no established cross-sectional imaging modality to detect fibrosis. New techniques, such as contrast-enhanced ultrasound and sonoelastography allow the assessment of vascularization and mechanical properties of stenotic bowel tissue, respectively. These techniques have shown great potential to characterize strictures in Crohn's disease. The aim of this review is to sum up the current knowledge on bowel ultrasound tools to discriminate inflammatory from fibrotic stenosis in Crohn's disease considering the most recent published studies in the field.

Cumulative phase delay imaging - A new contrast enhanced ultrasound modality

NASA Astrophysics Data System (ADS)

Demi, Libertario; van Sloun, Ruud J. G.; Wijkstra, Hessel; Mischi, Massimo

2015-10-01

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.

Multi-modality 3D breast imaging with X-Ray tomosynthesis and automated ultrasound.

PubMed

Sinha, Sumedha P; Roubidoux, Marilyn A; Helvie, Mark A; Nees, Alexis V; Goodsitt, Mitchell M; LeCarpentier, Gerald L; Fowlkes, J Brian; Chalek, Carl L; Carson, Paul L

2007-01-01

This study evaluated the utility of 3D automated ultrasound in conjunction with 3D digital X-Ray tomosynthesis for breast cancer detection and assessment, to better localize and characterize lesions in the breast. Tomosynthesis image volumes and automated ultrasound image volumes were acquired in the same geometry and in the same view for 27 patients. 3 MQSA certified radiologists independently reviewed the image volumes, visually correlating the images from the two modalities with in-house software. More sophisticated software was used on a smaller set of 10 cases, which enabled the radiologist to draw a 3D box around the suspicious lesion in one image set and isolate an anatomically correlated, similarly boxed region in the other modality image set. In the primary study, correlation was found to be moderately useful to the readers. In the additional study, using improved software, the median usefulness rating increased and confidence in localizing and identifying the suspicious mass increased in more than half the cases. As automated scanning and reading software techniques advance, superior results are expected.

A Guide to Analysing Tongue Motion from Ultrasound Images

ERIC Educational Resources Information Center

Stone, Maureen

2005-01-01

This paper is meant to be an introduction to and general reference for ultrasound imaging for new and moderately experienced users of the instrument. The paper consists of eight sections. The first explains how ultrasound works, including beam properties, scan types and machine features. The second section discusses image quality, including the…

Quantification of Macrocirculation and Microcirculation in Brain Using Ultrasound Perfusion Imaging.

PubMed

Vinke, Eline J; Eyding, Jens; de Korte, Chris; Slump, Cornelis H; van der Hoeven, Johannes G; Hoedemaekers, Cornelia W E

2018-01-01

The aim of this study was to investigate the feasibility of simultaneous visualization of the cerebral macrocirculation and microcirculation, using ultrasound perfusion imaging (UPI). In addition, we studied the sensitivity of this technique for detecting changes in cerebral blood flow (CBF). We performed an observational study in ten healthy volunteers. Ultrasound contrast was used for UPI measurements during normoventilation and hyperventilation. For the data analysis of the UPI measurements, an in-house algorithm was used to visualize the DICOM files, calculate parameter images and select regions of interest (ROIs). Next, time intensity curves (TIC) were extracted and perfusion parameters calculated. Both volume- and velocity-related perfusion parameters were significantly different between the macrocirculation and the parenchymal areas. Hyperventilation-induced decreases in CBF were detectable by UPI in both the macrocirculation and microcirculation, most consistently by the volume-related parameters. The method was safe, with no adverse effects in our population. Bedside quantification of CBF seems feasible and the technique has a favourable safety profile. Adjustment of current method is required to improve its diagnostic accuracy. Validation studies using a 'gold standard' are needed to determine the added value of UPI in neurocritical care monitoring.

Echo decorrelation imaging of ex vivo HIFU and bulk ultrasound ablation using image-treat arrays

NASA Astrophysics Data System (ADS)

Fosnight, Tyler R.; Hooi, Fong Ming; Colbert, Sadie B.; Keil, Ryan D.; Barthe, Peter G.; Mast, T. Douglas

2017-03-01

In this study, the ability of ultrasound echo decorrelation imaging to map and predict heat-induced cell death was tested using bulk ultrasound thermal ablation, high intensity focused ultrasound (HIFU) thermal ablation, and pulse-echo imaging of ex vivo liver tissue by a custom image-treat array. Tissue was sonicated at 5.0 MHz using either pulses of unfocused ultrasound (N=12) (7.5 s, 50.9-101.8 W/cm2 in situ spatial-peak, temporal-peak intensity) for bulk ablation or focused ultrasound (N=21) (1 s, 284-769 W/cm2 in situ spatial-peak, temporal-peak intensity and focus depth of 10 mm) for HIFU ablation. Echo decorrelation and integrated backscatter (IBS) maps were formed from radiofrequency pulse-echo images captured at 118 frames per second during 5.0 s rest periods, beginning 1.1 s after each sonication pulse. Tissue samples were frozen at -80˚C, sectioned, vitally stained, imaged, and semi-automatically segmented for receiver operating characteristic (ROC) analysis. ROC curves were constructed to assess prediction performance for echo decorrelation and IBS. Logarithmically scaled mean echo decorrelation in non-ablated and ablated tissue regions before and after electronic noise and motion correction were compared. Ablation prediction by echo decorrelation and IBS was significant for both focused and bulk ultrasound ablation. The log10-scaled mean echo decorrelation was significantly greater in regions of ablation for both HIFU and bulk ultrasound ablation. Echo decorrelation due to electronic noise and motion was significantly reduced by correction. These results suggest that ultrasound echo decorrelation imaging is a promising approach for real-time prediction of heat-induced cell death for guidance and monitoring of clinical thermal ablation, including radiofrequency ablation and HIFU.

Nanobubble-Affibody: Novel ultrasound contrast agents for targeted molecular ultrasound imaging of tumor.

PubMed

Yang, Hengli; Cai, Wenbin; Xu, Lei; Lv, Xiuhua; Qiao, Youbei; Li, Pan; Wu, Hong; Yang, Yilin; Zhang, Li; Duan, Yunyou

2015-01-01

Nanobubbles (NBs), as novel ultrasound contrast agents (UCAs), have attracted increasing attention in the field of molecular ultrasound imaging for tumors. However, the preparation of uniform-sized NBs is considered to be controversial, and poor tumor selectivity in in vivo imaging has been reported. In this study, we fabricated uniform nano-sized NBs (478.2 ± 29.7 nm with polydispersity index of 0.164 ± 0.044, n = 3) using a thin-film hydration method by controlling the thickness of phospholipid films; we then conjugated the NBs with Affibody molecules to produce nano-sized UCAs referred to as NB-Affibody with specific affinity to human epidermal growth factor receptor type 2 (HER2)-overexpressing tumors. NB-Affibody presented good ultrasound enhancement, demonstrating a peak intensity of 104.5 ± 2.1 dB under ultrasound contrast scanning. Ex vivo experiments further confirmed that the NB-Affibody conjugates were capable of targeting HER2-expressing tumor cells in vivo with high affinity. The newly prepared nano-sized NB-Affibody conjugates were observed to be novel targeted UCAs for efficient and safe specific molecular imaging and may have potential applications in early cancer quantitative diagnosis and targeted therapy in the future. Copyright © 2014 Elsevier Ltd. All rights reserved.

The role of ultrasound elastographic techniques in chronic liver disease: current status and future perspectives.

PubMed

Piscaglia, Fabio; Marinelli, Sara; Bota, Simona; Serra, Carla; Venerandi, Laura; Leoni, Simona; Salvatore, Veronica

2014-03-01

This review illustrates the state of the art clinical applications and the future perspectives of ultrasound elastographic methods for the evaluation of chronic liver diseases, including the most widely used and validated technique, transient elastography, followed by shear wave elastography and strain imaging elastography. Liver ultrasound elastography allows the non-invasive evaluation of liver stiffness, providing information regarding the stage of fibrosis, comparable to liver biopsy which is still considered the gold standard; in this way, it can help physicians in managing patients, including the decision as to when to start antiviral treatment. The characterization of focal liver lesions and the prognostic role of the elastographic technique in the prediction of complications of cirrhosis are still under investigation. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Comparison of portable and conventional ultrasound imaging in spinal curvature measurement

NASA Astrophysics Data System (ADS)

Yan, Christina; Tabanfar, Reza; Kempston, Michael; Borschneck, Daniel; Ungi, Tamas; Fichtinger, Gabor

2016-03-01

PURPOSE: In scoliosis monitoring, tracked ultrasound has been explored as a safer imaging alternative to traditional radiography. The use of ultrasound in spinal curvature measurement requires identification of vertebral landmarks, but bones have reduced visibility in ultrasound imaging and high quality ultrasound machines are often expensive and not portable. In this work, we investigate the image quality and measurement accuracy of a low cost and portable ultrasound machine in comparison to a standard ultrasound machine in scoliosis monitoring. METHODS: Two different kinds of ultrasound machines were tested on three human subjects, using the same position tracker and software. Spinal curves were measured in the same reference coordinate system using both ultrasound machines. Lines were defined by connecting two symmetric landmarks identified on the left and right transverse process of the same vertebrae, and spinal curvature was defined as the transverse process angle between two such lines, projected on the coronal plane. RESULTS: Three healthy volunteers were scanned by both ultrasound configurations. Three experienced observers localized transverse processes as skeletal landmarks and obtained transverse process angles in images obtained from both ultrasounds. The mean difference per transverse process angle measured was 3.00 +/-2.1°. 94% of transverse processes visualized in the Sonix Touch were also visible in the Telemed. Inter-observer error in the Telemed was 4.5° and 4.3° in the Sonix Touch. CONCLUSION: Price, convenience and accessibility suggest the Telemed to be a viable alternative in scoliosis monitoring, however further improvements in measurement protocol and image noise reduction must be completed before implementing the Telemed in the clinical setting.

Subresolution Displacements in Finite Difference Simulations of Ultrasound Propagation and Imaging.

PubMed

Pinton, Gianmarco F

2017-03-01

Time domain finite difference simulations are used extensively to simulate wave propagation. They approximate the wave field on a discrete domain with a grid spacing that is typically on the order of a tenth of a wavelength. The smallest displacements that can be modeled by this type of simulation are thus limited to discrete values that are integer multiples of the grid spacing. This paper presents a method to represent continuous and subresolution displacements by varying the impedance of individual elements in a multielement scatterer. It is demonstrated that this method removes the limitations imposed by the discrete grid spacing by generating a continuum of displacements as measured by the backscattered signal. The method is first validated on an ideal perfect correlation case with a single scatterer. It is subsequently applied to a more complex case with a field of scatterers that model an acoustic radiation force-induced displacement used in ultrasound elasticity imaging. A custom finite difference simulation tool is used to simulate propagation from ultrasound imaging pulses in the scatterer field. These simulated transmit-receive events are then beamformed into images, which are tracked with a correlation-based algorithm to determine the displacement. A linear predictive model is developed to analytically describe the relationship between element impedance and backscattered phase shift. The error between model and simulation is λ/ 1364 , where λ is the acoustical wavelength. An iterative method is also presented that reduces the simulation error to λ/ 5556 over one iteration. The proposed technique therefore offers a computationally efficient method to model continuous subresolution displacements of a scattering medium in ultrasound imaging. This method has applications that include ultrasound elastography, blood flow, and motion tracking. This method also extends generally to finite difference simulations of wave propagation, such as electromagnetic or

Imaging late capsular block syndrome: ultrasound biomicroscopy versus Scheimpflug camera.

PubMed

Kucukevcilioglu, Murat; Hurmeric, Volkan; Erdurman, Fazıl Cuneyt; Ceylan, Osman Melih

2011-11-01

We describe 2 patients with late capsular block syndrome whose anterior chamber morphology was evaluated with ultrasound biomicroscopy and Scheimpflug imaging before and after neodymium:YAG laser capsulotomy. Pretreatment ultrasound biomicroscopy examination showed significant capsular bag distension in both patients. Scheimpflug imaging failed to capture the posterior capsule displaced far behind the intraocular lens. Automatic anterior chamber depth measurements were incorrect with Scheimpflug imaging in 1 patient. Ultrasound biomicroscopy seems to be superior to Scheimpflug imaging in eyes with extremely distended capsular bags. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Efficient scatter model for simulation of ultrasound images from computed tomography data

NASA Astrophysics Data System (ADS)

D'Amato, J. P.; Lo Vercio, L.; Rubi, P.; Fernandez Vera, E.; Barbuzza, R.; Del Fresno, M.; Larrabide, I.

2015-12-01

Background and motivation: Real-time ultrasound simulation refers to the process of computationally creating fully synthetic ultrasound images instantly. Due to the high value of specialized low cost training for healthcare professionals, there is a growing interest in the use of this technology and the development of high fidelity systems that simulate the acquisitions of echographic images. The objective is to create an efficient and reproducible simulator that can run either on notebooks or desktops using low cost devices. Materials and methods: We present an interactive ultrasound simulator based on CT data. This simulator is based on ray-casting and provides real-time interaction capabilities. The simulation of scattering that is coherent with the transducer position in real time is also introduced. Such noise is produced using a simplified model of multiplicative noise and convolution with point spread functions (PSF) tailored for this purpose. Results: The computational efficiency of scattering maps generation was revised with an improved performance. This allowed a more efficient simulation of coherent scattering in the synthetic echographic images while providing highly realistic result. We describe some quality and performance metrics to validate these results, where a performance of up to 55fps was achieved. Conclusion: The proposed technique for real-time scattering modeling provides realistic yet computationally efficient scatter distributions. The error between the original image and the simulated scattering image was compared for the proposed method and the state-of-the-art, showing negligible differences in its distribution.

Trans-Stent B-Mode Ultrasound and Passive Cavitation Imaging.

PubMed

Haworth, Kevin J; Raymond, Jason L; Radhakrishnan, Kirthi; Moody, Melanie R; Huang, Shao-Ling; Peng, Tao; Shekhar, Himanshu; Klegerman, Melvin E; Kim, Hyunggun; McPherson, David D; Holland, Christy K

2016-02-01

Angioplasty and stenting of a stenosed artery enable acute restoration of blood flow. However, restenosis or a lack of re-endothelization can subsequently occur depending on the stent type. Cavitation-mediated drug delivery is a potential therapy for these conditions, but requires that particular types of cavitation be induced by ultrasound insonation. Because of the heterogeneity of tissue and stochastic nature of cavitation, feedback mechanisms are needed to determine whether the sustained bubble activity is induced. The objective of this study was to determine the feasibility of passive cavitation imaging through a metal stent in a flow phantom and an animal model. In this study, an endovascular stent was deployed in a flow phantom and in porcine femoral arteries. Fluorophore-labeled echogenic liposomes, a theragnostic ultrasound contrast agent, were injected proximal to the stent. Cavitation images were obtained by passively recording and beamforming the acoustic emissions from echogenic liposomes insonified with a low-frequency (500 kHz) transducer. In vitro experiments revealed that the signal-to-noise ratio for detecting stable cavitation activity through the stent was greater than 8 dB. The stent did not significantly reduce the signal-to-noise ratio. Trans-stent cavitation activity was also detected in vivo via passive cavitation imaging when echogenic liposomes were insonified by the 500-kHz transducer. When stable cavitation was detected, delivery of the fluorophore into the arterial wall was observed. Increased echogenicity within the stent was also observed when echogenic liposomes were administered. Thus, both B-mode ultrasound imaging and cavitation imaging are feasible in the presence of an endovascular stent in vivo. Demonstration of this capability supports future studies to monitor restenosis with contrast-enhanced ultrasound and pursue image-guided ultrasound-mediated drug delivery to inhibit restenosis. Copyright © 2016 World Federation for

Computer-aided diagnostic system for detection of Hashimoto thyroiditis on ultrasound images from a Polish population.

PubMed

Acharya, U Rajendra; Sree, S Vinitha; Krishnan, M Muthu Rama; Molinari, Filippo; Zieleźnik, Witold; Bardales, Ricardo H; Witkowska, Agnieszka; Suri, Jasjit S

2014-02-01

Computer-aided diagnostic (CAD) techniques aid physicians in better diagnosis of diseases by extracting objective and accurate diagnostic information from medical data. Hashimoto thyroiditis is the most common type of inflammation of the thyroid gland. The inflammation changes the structure of the thyroid tissue, and these changes are reflected as echogenic changes on ultrasound images. In this work, we propose a novel CAD system (a class of systems called ThyroScan) that extracts textural features from a thyroid sonogram and uses them to aid in the detection of Hashimoto thyroiditis. In this paradigm, we extracted grayscale features based on stationary wavelet transform from 232 normal and 294 Hashimoto thyroiditis-affected thyroid ultrasound images obtained from a Polish population. Significant features were selected using a Student t test. The resulting feature vectors were used to build and evaluate the following 4 classifiers using a 10-fold stratified cross-validation technique: support vector machine, decision tree, fuzzy classifier, and K-nearest neighbor. Using 7 significant features that characterized the textural changes in the images, the fuzzy classifier had the highest classification accuracy of 84.6%, sensitivity of 82.8%, specificity of 87.0%, and a positive predictive value of 88.9%. The proposed ThyroScan CAD system uses novel features to noninvasively detect the presence of Hashimoto thyroiditis on ultrasound images. Compared to manual interpretations of ultrasound images, the CAD system offers a more objective interpretation of the nature of the thyroid. The preliminary results presented in this work indicate the possibility of using such a CAD system in a clinical setting after evaluating it with larger databases in multicenter clinical trials.

Noninvasive thermal ablation of hepatocellular carcinoma by using magnetic resonance imaging-guided focused ultrasound.

PubMed

Jolesz, Ferenc A; Hynynen, Kullervo; McDannold, Nathan; Freundlich, David; Kopelman, Doron

2004-11-01

A number of minimally invasive methods have been tested for the thermal ablation of liver tumors as an alternative to surgical resection. The use of focused ultrasound transducers to ablate deep tumors offers the first completely noninvasive alternative to these techniques. By increasing the flexibility of this technology with modern phased-array transducer design and by combining it with magnetic resonance imaging for targeting and online guidance, a powerful tool results with the potential to offer treatment to a larger population of patients, to reduce trauma to the patient, and to reduce the cost of treatment. In this article, we review previous work with focused ultrasound in the liver and recent experimental results with magnetic resonance imaging guidance.

Photo-Acoustic Ultrasound Imaging to Distinguish Benign from Malignant Prostate Cancer

DTIC Science & Technology

2016-09-01

from the inside out. Ultrasound imaging provides a basic view of the structure of the prostate while photoacoustic contrast is predicted to enhance...University Page 2 of 13 1. INTRODUCTION: Ultrasound imaging uses sound waves at frequencies above the human hearing range to image organs within the body...An ultrasound transducer delivers a pulse of acoustic energy into the area of interest and listens for the echoes which return as the sound waves

WE-H-209-00: Carson/Zagzebski Distinguished Lectureship: Image Guided Ultrasound Therapy

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

NONE

Focused ultrasound has been shown to be the only method that allows noninvasive thermal coagulation of tissues and recently this potential has been explored for image-guided drug delivery. In this presentation, the advances in ultrasound phased array technology for energy delivery, exposure monitoring and control will be discussed. Experimental results from novel multi-frequency transmit/receive arrays will be presented. In addition, the feasibility of fully electronically focused and steered high power arrays with many thousands of transducer elements will be discussed. Finally, some of the recent clinical and preclinical results for the treatment of brain disease will be reviewed. Learning Objectives:more » Introduce FUS therapy principles and modern techniques Discuss use of FUS for drug delivery Cover the technology required to deliver FUS and monitor therapy Present clinical examples of the uses of these techniques This research was supported by funding from The Canada Research Chair Program, Grants from CIHR and NIH (no. EB003268).; K. Hynynen, Canada Foundation for Innovation; Canadian Institutes of Health Research; Focused Ultrasound Surgery Foundation; Canada Research Chair Program; Natural Sciences and Engineering Research Council of Canada; Ontario Research Fund; National Institutes of Health; Canadian Cancer Society Research Institute; The Weston Brain Institute; Harmonic Medical; Focused Ultrasound Instruments.« less

Hybrid Photoacoustic/Ultrasound Tomograph for Real-Time Finger Imaging.

PubMed

Oeri, Milan; Bost, Wolfgang; Sénégond, Nicolas; Tretbar, Steffen; Fournelle, Marc

2017-10-01

We report a target-enclosing, hybrid tomograph with a total of 768 elements based on capacitive micromachined ultrasound transducer technology and providing fast, high-resolution 2-D/3-D photoacoustic and ultrasound tomography tailored to finger imaging. A freely programmable ultrasound beamforming platform sampling data at 80 MHz was developed to realize plane wave transmission under multiple angles. A multiplexing unit enables the connection and control of a large number of elements. Fast image reconstruction is provided by GPU processing. The tomograph is composed of four independent and fully automated movable arc-shaped transducers, allowing imaging of all three finger joints. The system benefits from photoacoustics, yielding high optical contrast and enabling visualization of finger vascularization, and ultrasound provides morphologic information on joints and surrounding tissue. A diode-pumped, Q-switched Nd:YAG laser and an optical parametric oscillator are used to broaden the spectrum of emitted wavelengths to provide multispectral imaging. Custom-made optical fiber bundles enable illumination of the region of interest in the plane of acoustic detection. Precision in positioning of the probe in motion is ensured by use of a motor-driven guide slide. The current position of the probe is encoded by the stage and used to relate ultrasound and photoacoustic signals to the corresponding region of interest of the suspicious finger joint. The system is characterized in phantoms and a healthy human finger in vivo. The results obtained promise to provide new opportunities in finger diagnostics and establish photoacoustic/ultrasound-tomography in medical routine. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Mathematical models used in segmentation and fractal methods of 2-D ultrasound images

NASA Astrophysics Data System (ADS)

Moldovanu, Simona; Moraru, Luminita; Bibicu, Dorin

2012-11-01

Mathematical models are widely used in biomedical computing. The extracted data from images using the mathematical techniques are the "pillar" achieving scientific progress in experimental, clinical, biomedical, and behavioural researches. This article deals with the representation of 2-D images and highlights the mathematical support for the segmentation operation and fractal analysis in ultrasound images. A large number of mathematical techniques are suitable to be applied during the image processing stage. The addressed topics cover the edge-based segmentation, more precisely the gradient-based edge detection and active contour model, and the region-based segmentation namely Otsu method. Another interesting mathematical approach consists of analyzing the images using the Box Counting Method (BCM) to compute the fractal dimension. The results of the paper provide explicit samples performed by various combination of methods.

Cumulative phase delay imaging - A new contrast enhanced ultrasound modality

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

Demi, Libertario, E-mail: l.demi@tue.nl; Sloun, Ruud J. G. van; Mischi, Massimo

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 platemore » (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.« less

[Anterior segment tumor imaging: advantages of ultrasound (10, 20 and 50 MHz) and optical coherence tomography].

PubMed

Siahmed, K; Berges, O; Desjardins, L; Lumbroso, L; Brasseur, G

2004-02-01

Detail the role of different imaging techniques for diagnosis of tumors of the iris. Sixty-one tumors of the iris were explored using ultrasound at 10 and 20MHz (Cinescan, BVI Quantel Medical) and 50MHz (UBM, Paradigm) and optical coherence tomography (OCT) (Humphrey Zeiss). Ultrasound should be used at frequencies of 20MHz or greater to precisely characterize, localize and measure a lesion. Ultrasound biomicroscopy (UBM) is inadequate to measure large tumors (extending toward the back of the ciliary body), because of the transducer and the considerably lower image quality caused by the lesion. Ultrasound alone cannot characterize a solid lesion, and moreover cannot differentiate benign and malignant lesions. Clinical notions are also important in diagnosis and patient management. OCT recognizes whether a lesion is liquid or solid in certain cases. With a tumor that seems solid, a 50MHz examination must be done rapidly, and if the entire lesion is difficult to see, a 20MHz ultrasound should be used. With a protruding iris, high-frequency ultrasound and OCT differentiate a cystic lesion from a solid mass, but only BMU provides a precise measurement and regular surveillance capabilities.

A preliminary evaluation of self-made nanobubble in contrast-enhanced ultrasound imaging

NASA Astrophysics Data System (ADS)

Li, Chunfang; Wu, Kaizhi; Li, Jing; Liu, Haijuan; Zhou, Qibing; Ding, Mingyue

2014-03-01

Nanoscale bubbles (nanobubbles) have been reported to improve contrast in tumor-targeted ultrasound imaging due to the enhanced permeation and retention effects at tumor vascular leaks. In this work, a self-made nanobubble ultrasound contrast agent was preliminarily characterized and evaluated in-vitro and in-vivo. Fundamental properties such as morphology appearance, size distribution, zeta potential, bubble concentration (bubble numbers per milliliter contrast agent suspension) and the stability of nanobubbles were assessed by light microscope and particle sizing analysis. Then the concentration intensity curve and time intensity curves (TICs) were acquired by ultrasound imaging experiment in-vitro. Finally, the contrast-enhanced ultrasonography was performed on rat to investigate the procedure of liver perfusion. The results showed that the nanobubbles had good shape and uniform distribution with the average diameter of 507.9 nm, polydispersity index (PDI) of 0.527, and zeta potential of -19.17 mV. Significant contrast enhancement was observed in in-vitro ultrasound imaging, demonstrating that the self-made nanobubbles can enhance the contrast effect of ultrasound imaging efficiently in-vitro. Slightly contrast enhancement was observed in in-vivo ultrasound imaging, indicating that the nanobubbles are not stable enough in-vivo. Future work will be focused on improving the ultrasonic imaging performance, stability, and antibody binding of the nanoscale ultrasound contrast agent.

Microwave-excited ultrasound and thermoacoustic dual imaging

NASA Astrophysics Data System (ADS)

Ding, Wenzheng; Ji, Zhong; Xing, Da

2017-05-01

We designed a microwave-excited ultrasound (MUI) and thermoacoustic dual imaging system. Under the pulsed microwave excitation, the piezoelectric transducer used for thermoacoustic signal detection will also emit a highly directional ultrasonic beam based on the inverse piezoelectric effect. With this beam, the ultrasonic transmitter circuitry of the traditional ultrasound imaging (TUI) system can be replaced by a microwave source. In other words, TUI can be fully integrated into the thermoacoustic imaging system by sharing the microwave excitation source and the transducer. Moreover, the signals of the two imaging modalities do not interfere with each other due to the existence of the sound path difference, so that MUI can be performed simultaneously with microwave-induced thermoacoustic imaging. In the study, the performance characteristics and imaging capabilities of this hybrid system are demonstrated. The results indicate that our design provides one easy method for low-cost platform integration and has the potential to offer a clinically useful dual-modality tool for the detection of accurate diseases.

Ultrasound-guided synovial Tru-cut biopsy: indications, technique, and outcome in 111 cases.

PubMed

Sitt, Jacqueline C M; Griffith, James F; Lai, Fernand M; Hui, Mamie; Chiu, K H; Lee, Ryan K L; Ng, Alex W H; Leung, Jason

2017-05-01

To investigate the diagnostic performance of ultrasound-guided synovial biopsy. Clinical notes, pathology and microbiology reports, ultrasound and other imaging studies of 100 patients who underwent 111 ultrasound-guided synovial biopsies were reviewed. Biopsies were compared with the final clinical diagnosis established after synovectomy (n = 43) or clinical/imaging follow-up (n = 57) (mean 30 months). Other than a single vasovagal episode, no complication of synovial biopsy was encountered. One hundred and seven (96 %) of the 111 biopsies yielded synovium histologically. Pathology ± microbiology findings for these 107 conclusive biopsies comprised synovial tumour (n = 30, 28 %), synovial infection (n = 18, 17 %), synovial inflammation (n = 45, 42 %), including gouty arthritis (n = 3), and no abnormality (n = 14, 13 %). The accuracy, sensitivity, and specificity of synovial biopsy was 99 %, 97 %, and 100 % for synovial tumour; 100 %, 100 %, and 100 % for native joint infection; and 78 %, 45 %, and 100 % for prosthetic joint infection. False-negative synovial biopsy did not seem to be related to antibiotic therapy. Ultrasound-guided Tru-cut synovial biopsy is a safe and reliable technique with a high diagnostic yield for diagnosing synovial tumour and also, most likely, for joint infection. Regarding joint infection, synovial biopsy of native joints seems to have a higher diagnostic yield than that for infected prosthetic joints. • Ultrasound-guided Tru-cut synovial biopsy has high accuracy (99 %) for diagnosing synovial tumour. • It has good accuracy, sensitivity, and high specificity for diagnosis of joint infection. • Synovial biopsy of native joints works better than biopsy of prosthetic joints. • A negative synovial biopsy culture from a native joint largely excludes septic arthritis. • Ultrasound-guided Tru-cut synovial biopsy is a safe and well-tolerated procedure.

Imaging of Groin Pain: Magnetic Resonance and Ultrasound Imaging Features

PubMed Central

Lee, Susan C.; Endo, Yoshimi; Potter, Hollis G.

2017-01-01

Context: Evaluation of groin pain in athletes may be challenging as pain is typically poorly localized and the pubic symphyseal region comprises closely approximated tendons and muscles. As such, magnetic resonance imaging (MRI) and ultrasound (US) may help determine the etiology of groin pain. Evidence Acquisition: A PubMed search was performed using the following search terms: ultrasound, magnetic resonance imaging, sports hernia, athletic pubalgia, and groin pain. Date restrictions were not placed on the literature search. Study Design: Clinical review. Level of Evidence: Level 4. Results: MRI is sensitive in diagnosing pathology in groin pain. Not only can MRI be used to image rectus abdominis/adductor longus aponeurosis and pubic bone pathology, but it can also evaluate other pathology within the hip and pelvis. MRI is especially helpful when groin pain is poorly localized. Real-time capability makes ultrasound useful in evaluating the pubic symphyseal region, as it can be used for evaluation and treatment. Conclusion: MRI and US are valuable in diagnosing pathology in athletes with groin pain, with the added utility of treatment using US-guided intervention. Strength-of Recommendation Taxonomy: C PMID:28850315

Comparative Effectiveness of Targeted Prostate Biopsy Using Magnetic Resonance Imaging Ultrasound Fusion Software and Visual Targeting: a Prospective Study.

PubMed

Lee, Daniel J; Recabal, Pedro; Sjoberg, Daniel D; Thong, Alan; Lee, Justin K; Eastham, James A; Scardino, Peter T; Vargas, Hebert Alberto; Coleman, Jonathan; Ehdaie, Behfar

2016-09-01

We compared the diagnostic outcomes of magnetic resonance-ultrasound fusion and visually targeted biopsy for targeting regions of interest on prostate multiparametric magnetic resonance imaging. Patients presenting for prostate biopsy with regions of interest on multiparametric magnetic resonance imaging underwent magnetic resonance imaging targeted biopsy. For each region of interest 2 visually targeted cores were obtained, followed by 2 cores using a magnetic resonance-ultrasound fusion device. Our primary end point was the difference in the detection of high grade (Gleason 7 or greater) and any grade cancer between visually targeted and magnetic resonance-ultrasound fusion, investigated using McNemar's method. Secondary end points were the difference in detection rate by biopsy location using a logistic regression model and the difference in median cancer length using the Wilcoxon signed rank test. We identified 396 regions of interest in 286 men. The difference in the detection of high grade cancer between magnetic resonance-ultrasound fusion biopsy and visually targeted biopsy was -1.4% (95% CI -6.4 to 3.6, p=0.6) and for any grade cancer the difference was 3.5% (95% CI -1.9 to 8.9, p=0.2). Median cancer length detected by magnetic resonance-ultrasound fusion and visually targeted biopsy was 5.5 vs 5.8 mm, respectively (p=0.8). Magnetic resonance-ultrasound fusion biopsy detected 15% more cancers in the transition zone (p=0.046) and visually targeted biopsy detected 11% more high grade cancer at the prostate base (p=0.005). Only 52% of all high grade cancers were detected by both techniques. We found no evidence of a significant difference in the detection of high grade or any grade cancer between visually targeted and magnetic resonance-ultrasound fusion biopsy. However, the performance of each technique varied in specific biopsy locations and the outcomes of both techniques were complementary. Combining visually targeted biopsy and magnetic resonance-ultrasound

Multiresolution generalized N dimension PCA for ultrasound image denoising

PubMed Central

2014-01-01

Background Ultrasound images are usually affected by speckle noise, which is a type of random multiplicative noise. Thus, reducing speckle and improving image visual quality are vital to obtaining better diagnosis. Method In this paper, a novel noise reduction method for medical ultrasound images, called multiresolution generalized N dimension PCA (MR-GND-PCA), is presented. In this method, the Gaussian pyramid and multiscale image stacks on each level are built first. GND-PCA as a multilinear subspace learning method is used for denoising. Each level is combined to achieve the final denoised image based on Laplacian pyramids. Results The proposed method is tested with synthetically speckled and real ultrasound images, and quality evaluation metrics, including MSE, SNR and PSNR, are used to evaluate its performance. Conclusion Experimental results show that the proposed method achieved the lowest noise interference and improved image quality by reducing noise and preserving the structure. Our method is also robust for the image with a much higher level of speckle noise. For clinical images, the results show that MR-GND-PCA can reduce speckle and preserve resolvable details. PMID:25096917

Carotid stiffness change over the cardiac cycle by ultrafast ultrasound imaging in healthy volunteers and vascular Ehlers-Danlos syndrome.

PubMed

Mirault, Tristan; Pernot, Mathieu; Frank, Michael; Couade, Mathieu; Niarra, Ralph; Azizi, Michel; Emmerich, Joseph; Jeunemaître, Xavier; Fink, Mathias; Tanter, Mickaël; Messas, Emmanuel

2015-09-01

Arterial stiffness is related to age and collagen properties of the arterial wall and can be indirectly evaluated by the pulse wave velocity (PWV). Ultrafast ultrasound imaging, a unique ultrahigh frame rate technique (>10, 000 images/s), recently emerged enabling direct measurement of carotid PWV and its variation over the cardiac cycle. Our goal was to characterize the carotid diastolic-systolic arterial stiffening using ultrafast ultrasound imaging in healthy individuals and in vascular Ehlers-Danlos syndrome (vEDS), in which collagen type III is defectuous. Ultrafast ultrasound imaging was performed on common carotids of 102 healthy individuals and 37 consecutive patients with vEDS. Results are mean ± standard deviation. Carotid ultrafast ultrasound imaging PWV in healthy individuals was 5.6 ± 1.2 in early systole and 7.3 ± 2.0  m/s in end systole, and correlated with age (r = 0.48; P < 0.0001 and r = 0.68; P < 0.0001, respectively). Difference between early and end-systole PWV increased with age independently of blood pressure (r = 0.54; P < 0.0001). In patients with vEDS, ultrafast ultrasound imaging PWV was 6.0 ± 1.5 in early systole and 6.7 ± 1.5  m/s in end systole. Carotid stiffness change over the cardiac cycle was lower than in healthy people (0.021 vs. 0.057  m/s per mmHg; P = 0.0035). Ultrafast ultrasound imaging can evaluate carotid PWV and its variation over the cardiac cycle. This allowed to demonstrate the age-induced increase of the arterial diastolic-systolic stiffening in healthy people and a lower stiffening in vEDS, both characterized by arterial complications. We believe that this easy-to-use technique could offer the opportunity to go beyond the diastolic PWV to better characterize arterial stiffness change with age or other collagen alterations.

Simultaneous three-dimensional laser-ultrasound and photoacoustic imaging

NASA Astrophysics Data System (ADS)

Wurzinger, Gerhild; Nuster, Robert; Schmitner, Nicole; Gratt, Sibylle; Paltauf, Günther

2013-06-01

A purely optical setup for simultaneous photoacoustic (PA) and laser-ultrasound (US) tomography is presented. It is shown that combined imaging can be achieved by using the same laser pulse for photoacoustic generation and for launching a broadband ultrasound pulse from an optically absorbing target. Detection of the laser-generated plane waves that have been scattered at the imaging object and of the photoacoustic signals emitted from the sample is done interferometrically. This way data for PA and US imaging are acquired within one single measurement. Distinction between the signals is possible due to their different times of flight. After data separation, image reconstruction is done using standard back-projection algorithms. The resolution of the setup was estimated and images of a zebra fish are shown, demonstrating the complementary information of the two imaging modalities.

Ultrasound-guided venous access for pacemakers and defibrillators.

PubMed

Seto, Arnold H; Jolly, Aaron; Salcedo, Jonathan

2013-03-01

Ultrasound guidance is widely recommended to reduce the risk of complications during central venous catheter placement. However, ultrasound guidance is not commonly utilized for implanting leads for cardiac rhythm management devices. We describe our technique of ultrasound-guided pacemaker implantation, including a novel pull-through technique that allows percutaneous guidewire insertion prior to the first incision. We review the literature and recent advances in ultrasound imaging technology that may facilitate the adoption of ultrasound guidance. Ultrasound guidance provides a safe and rapid technique for extrathoracic subclavian or axillary venous lead placement. © 2012 Wiley Periodicals, Inc.

An automated technique for potential differentiation of ovarian mature teratomas from other benign tumours using neural networks classification of 2D ultrasound static images: a pilot study

NASA Astrophysics Data System (ADS)

Al-karawi, Dhurgham; Sayasneh, A.; Al-Assam, Hisham; Jassim, Sabah; Page, N.; Timmerman, D.; Bourne, T.; Du, Hongbo

2017-05-01

Ovarian cysts are a common pathology in women of all age groups. It is estimated that 5-10% of women have a surgical intervention to remove an ovarian cyst in their lifetime. Given this frequency rate, characterization of ovarian masses is essential for optimal management of patients. Patients with benign ovarian masses can be managed conservatively if they are asymptomatic. Mature teratomas are common benign ovarian cysts that occur, in most cases, in premenopausal women. These ovarian cysts can contain different types of human tissue including bone, cartilage, fat, hair, or other tissue. If they are causing no symptoms, they can be harmless and may not require surgery. Subjective assessment by ultrasound examiners has a high diagnostic accuracy when characterising mature teratomas from other types of tumours. The aim of this study is to develop a computerised technique with the potential to characterise mature teratomas and distinguish them from other types of benign ovarian tumours. Local Binary Pattern (LBP) was applied to extract texture features that are specific in distinguishing teratomas. Neural Networks (NN) was then used as a classifier for recognising mature teratomas. A pilot sample set of 130 B-mode static ovarian ultrasound images (41 mature teratomas tumours and 89 other types of benign tumours) was used to test the effectiveness of the proposed technique. Test results show an average accuracy rate of 99.4% with a sensitivity of 100%, specificity of 98.8% and positive predictive value of 98.9%. This study demonstrates that the NN and LBP techniques can accurately classify static 2D B-mode ultrasound images of benign ovarian masses into mature teratomas and other types of benign tumours.

MO-DE-210-03: Ultrasound imaging is an attractive method for image guided radiation treatment (IGRT), by itself or to complement other imaging modalities

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

Ding, K.

Ultrasound imaging is an attractive method for image guided radiation treatment (IGRT), by itself or to complement other imaging modalities. It is inexpensive, portable and provides good soft tissue contrast. For challenging soft tissue targets such as pancreatic cancer, ultrasound imaging can be used in combination with pre-treatment MRI and/or CT to transfer important anatomical features for target localization at time of treatment. The non-invasive and non-ionizing nature of ultrasound imaging is particularly powerful for intra-fraction localization and monitoring. Recognizing these advantages, efforts are being made to incorporate novel robotic approaches to position and manipulate the ultrasound probe during irradiation.more » These recent enabling developments hold potential to bring ultrasound imaging to a new level of IGRT applications. However, many challenges, not limited to image registration, robotic deployment, probe interference and image acquisition rate, need to be addressed to realize the full potential of IGRT with ultrasound imaging. Learning Objectives: Understand the benefits and limitations in using ultrasound to augment MRI and/or CT for motion monitoring during radiation therapy delivery. Understanding passive and active robotic approaches to implement ultrasound imaging for intra-fraction monitoring. Understand issues of probe interference with radiotherapy treatment. Understand the critical clinical workflow for effective and reproducible IGRT using ultrasound guidance. The work of X.L. is supported in part by Elekta; J.W. and K.D. is supported in part by a NIH grant R01 CA161613 and by Elekta; D.H. is support in part by a NIH grant R41 CA174089.« less

Computer-Aided Characterization and Diagnosis of Diffuse Liver Diseases Based on Ultrasound Imaging: A Review.

PubMed

Bharti, Puja; Mittal, Deepti; Ananthasivan, Rupa

2016-04-19

Diffuse liver diseases, such as hepatitis, fatty liver, and cirrhosis, are becoming a leading cause of fatality and disability all over the world. Early detection and diagnosis of these diseases is extremely important to save lives and improve effectiveness of treatment. Ultrasound imaging, a noninvasive diagnostic technique, is the most commonly used modality for examining liver abnormalities. However, the accuracy of ultrasound-based diagnosis depends highly on expertise of radiologists. Computer-aided diagnosis systems based on ultrasound imaging assist in fast diagnosis, provide a reliable "second opinion" for experts, and act as an effective tool to measure response of treatment on patients undergoing clinical trials. In this review, we first describe appearance of liver abnormalities in ultrasound images and state the practical issues encountered in characterization of diffuse liver diseases that can be addressed by software algorithms. We then discuss computer-aided diagnosis in general with features and classifiers relevant to diffuse liver diseases. In later sections of this paper, we review the published studies and describe the key findings of those studies. A concise tabular summary comparing image database, features extraction, feature selection, and classification algorithms presented in the published studies is also exhibited. Finally, we conclude with a summary of key findings and directions for further improvements in the areas of accuracy and objectiveness of computer-aided diagnosis. © The Author(s) 2016.

Harmonic motion imaging for focused ultrasound (HMIFU): a fully integrated technique for sonication and monitoring of thermal ablation in tissues.

PubMed

Maleke, C; Konofagou, E E

2008-03-21

FUS (focused ultrasound), or HIFU (high-intensity-focused ultrasound) therapy, a minimally or non-invasive procedure that uses ultrasound to generate thermal necrosis, has been proven successful in several clinical applications. This paper discusses a method for monitoring thermal treatment at different sonication durations (10 s, 20 s and 30 s) using the amplitude-modulated (AM) harmonic motion imaging for focused ultrasound (HMIFU) technique in bovine liver samples in vitro. The feasibility of HMI for characterizing mechanical tissue properties has previously been demonstrated. Here, a confocal transducer, combining a 4.68 MHz therapy (FUS) and a 7.5 MHz diagnostic (pulse-echo) transducer, was used. The therapy transducer was driven by a low-frequency AM continuous signal at 25 Hz, producing a stable harmonic radiation force oscillating at the modulation frequency. A pulser/receiver was used to drive the pulse-echo transducer at a pulse repetition frequency (PRF) of 5.4 kHz. Radio-frequency (RF) signals were acquired using a standard pulse-echo technique. The temperature near the ablation region was simultaneously monitored. Both RF signals and temperature measurements were obtained before, during and after sonication. The resulting axial tissue displacement was estimated using one-dimensional cross correlation. When temperature at the focal zone was above 48 degrees C during heating, the coagulation necrosis occurred and tissue damage was irreversible. The HMI displacement profiles in relation to the temperature and sonication durations were analyzed. At the beginning of heating, the temperature at the focus increased sharply, while the tissue stiffness decreased resulting in higher HMI displacements. This was confirmed by an increase of 0.8 microm degrees C(-1)(r=0.93, p<.005). After sustained heating, the tissue became irreversibly stiffer, followed by an associated decrease in the HMI displacement (-0.79 microm degrees C(-1), r=-0.92, p<0.001). Repeated

Combining Ultrasound Pulse-Echo and Transmission Computed Tomography for Quantitative Imaging the Cortical Shell of Long Bone Replicas

NASA Astrophysics Data System (ADS)

Shortell, Matthew P.; Althomali, Marwan A. M.; Wille, Marie-Luise; Langton, Christian M.

2017-11-01

We demonstrate a simple technique for quantitative ultrasound imaging of the cortical shell of long bone replicas. Traditional ultrasound computed tomography instruments use the transmitted or reflected waves for separate reconstructions but suffer from strong refraction artefacts in highly heterogenous samples such as bones in soft tissue. The technique described here simplifies the long bone to a two-component composite and uses both the transmitted and reflected waves for reconstructions, allowing the speed of sound and thickness of the cortical shell to be calculated accurately. The technique is simple to implement, computationally inexpensive and sample positioning errors are minimal.

Integrated ultrasound and magnetic resonance imaging for simultaneous temperature and cavitation monitoring during focused ultrasound therapies

PubMed Central

Arvanitis, Costas D.; McDannold, Nathan

2013-01-01

Purpose: Ultrasound can be used to noninvasively produce different bioeffects via viscous heating, acoustic cavitation, or their combination, and these effects can be exploited to develop a wide range of therapies for cancer and other disorders. In order to accurately localize and control these different effects, imaging methods are desired that can map both temperature changes and cavitation activity. To address these needs, the authors integrated an ultrasound imaging array into an MRI-guided focused ultrasound (MRgFUS) system to simultaneously visualize thermal and mechanical effects via passive acoustic mapping (PAM) and MR temperature imaging (MRTI), respectively. Methods: The system was tested with an MRgFUS system developed for transcranial sonication for brain tumor ablation in experiments with a tissue mimicking phantom and a phantom-filled ex vivo macaque skull. In experiments on cavitation-enhanced heating, 10 s continuous wave sonications were applied at increasing power levels (30–110 W) until broadband acoustic emissions (a signature for inertial cavitation) were evident. The presence or lack of signal in the PAM, as well as its magnitude and location, were compared to the focal heating in the MRTI. Additional experiments compared PAM with standard B-mode ultrasound imaging and tested the feasibility of the system to map cavitation activity produced during low-power (5 W) burst sonications in a channel filled with a microbubble ultrasound contrast agent. Results: When inertial cavitation was evident, localized activity was present in PAM and a marked increase in heating was observed in MRTI. The location of the cavitation activity and heating agreed on average after registration of the two imaging modalities; the distance between the maximum cavitation activity and focal heating was −3.4 ± 2.1 mm and −0.1 ± 3.3 mm in the axial and transverse ultrasound array directions, respectively. Distortions and other MRI issues introduced small

Integrated ultrasound and magnetic resonance imaging for simultaneous temperature and cavitation monitoring during focused ultrasound therapies.

PubMed

Arvanitis, Costas D; McDannold, Nathan

2013-11-01

Ultrasound can be used to noninvasively produce different bioeffects via viscous heating, acoustic cavitation, or their combination, and these effects can be exploited to develop a wide range of therapies for cancer and other disorders. In order to accurately localize and control these different effects, imaging methods are desired that can map both temperature changes and cavitation activity. To address these needs, the authors integrated an ultrasound imaging array into an MRI-guided focused ultrasound (MRgFUS) system to simultaneously visualize thermal and mechanical effects via passive acoustic mapping (PAM) and MR temperature imaging (MRTI), respectively. The system was tested with an MRgFUS system developed for transcranial sonication for brain tumor ablation in experiments with a tissue mimicking phantom and a phantom-filled ex vivo macaque skull. In experiments on cavitation-enhanced heating, 10 s continuous wave sonications were applied at increasing power levels (30-110 W) until broadband acoustic emissions (a signature for inertial cavitation) were evident. The presence or lack of signal in the PAM, as well as its magnitude and location, were compared to the focal heating in the MRTI. Additional experiments compared PAM with standard B-mode ultrasound imaging and tested the feasibility of the system to map cavitation activity produced during low-power (5 W) burst sonications in a channel filled with a microbubble ultrasound contrast agent. When inertial cavitation was evident, localized activity was present in PAM and a marked increase in heating was observed in MRTI. The location of the cavitation activity and heating agreed on average after registration of the two imaging modalities; the distance between the maximum cavitation activity and focal heating was -3.4 ± 2.1 mm and -0.1 ± 3.3 mm in the axial and transverse ultrasound array directions, respectively. Distortions and other MRI issues introduced small uncertainties in the PAM�

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

PubMed

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

2014-11-01

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

Imaging of plantar fascia disorders: findings on plain radiography, ultrasound and magnetic resonance imaging.

PubMed

Draghi, Ferdinando; Gitto, Salvatore; Bortolotto, Chandra; Draghi, Anna Guja; Ori Belometti, Gioia

2017-02-01

Plantar fascia (PF) disorders commonly cause heel pain and disability in the general population. Imaging is often required to confirm diagnosis. This review article aims to provide simple and systematic guidelines for imaging assessment of PF disease, focussing on key findings detectable on plain radiography, ultrasound and magnetic resonance imaging (MRI). Sonographic characteristics of plantar fasciitis include PF thickening, loss of fibrillar structure, perifascial collections, calcifications and hyperaemia on Doppler imaging. Thickening and signal changes in the PF as well as oedema of adjacent soft tissues and bone marrow can be assessed on MRI. Radiographic findings of plantar fasciitis include PF thickening, cortical irregularities and abnormalities in the fat pad located deep below the PF. Plantar fibromatosis appears as well-demarcated, nodular thickenings that are iso-hypoechoic on ultrasound and show low-signal intensity on MRI. PF tears present with partial or complete fibre interruption on both ultrasound and MRI. Imaging description of further PF disorders, including xanthoma, diabetic fascial disease, foreign-body reactions and plantar infections, is detailed in the main text. Ultrasound and MRI should be considered as first- and second-line modalities for assessment of PF disorders, respectively. Indirect findings of PF disease can be ruled out on plain radiography. Teaching Points • PF disorders commonly cause heel pain and disability in the general population.• Imaging is often required to confirm diagnosis or reveal concomitant injuries.• Ultrasound and MRI respectively represent the first- and second-line modalities for diagnosis.• Indirect findings of PF disease can be ruled out on plain radiography.

In vivo photoacoustics and high frequency ultrasound imaging of mechanical high intensity focused ultrasound (HIFU) ablation.

PubMed

Daoudi, Khalid; Hoogenboom, Martijn; den Brok, Martijn; Eikelenboom, Dylan; Adema, Gosse J; Fütterer, Jürgen J; de Korte, Chris L

2017-04-01

The thermal effect of high intensity focused ultrasound (HIFU) has been clinically exploited over a decade, while the mechanical HIFU is still largely confined to laboratory investigations. This is in part due to the lack of adequate imaging techniques to better understand the in-vivo pathological and immunological effects caused by the mechanical treatment. In this work, we explore the use of high frequency ultrasound (US) and photoacoustics (PA) as a potential tool to evaluate the effect of mechanical ablation in-vivo , e.g. boiling histotripsy. Two mice bearing a neuroblastoma tumor in the right leg were ablated using an MRI-HIFU system conceived for small animals and monitored using MRI thermometry. High frequency US and PA imaging were performed before and after the HIFU treatment. Afterwards, the tumor was resected for further assessment and evaluation of the ablated region using histopathology. High frequency US imaging revealed the presence of liquefied regions in the treated area together with fragmentized tissue which appeared with different reflecting proprieties compared to the surrounding tissue. Photoacoustic imaging on the other hand revealed the presence of deoxygenated blood within the tumor after the ablation due to the destruction of blood vessel network while color Doppler imaging confirmed the blood vessel network destruction within the tumor. The treated area and the presence of red blood cells detected by photoacoustics were further confirmed by the histopathology. This feasibility study demonstrates the potential of high frequency US and PA approach for assessing in-vivo the effect of mechanical HIFU tumor ablation.

In vivo photoacoustics and high frequency ultrasound imaging of mechanical high intensity focused ultrasound (HIFU) ablation

PubMed Central

Daoudi, Khalid; Hoogenboom, Martijn; den Brok, Martijn; Eikelenboom, Dylan; Adema, Gosse J.; Fütterer, Jürgen J.; de Korte, Chris L.

2017-01-01

The thermal effect of high intensity focused ultrasound (HIFU) has been clinically exploited over a decade, while the mechanical HIFU is still largely confined to laboratory investigations. This is in part due to the lack of adequate imaging techniques to better understand the in-vivo pathological and immunological effects caused by the mechanical treatment. In this work, we explore the use of high frequency ultrasound (US) and photoacoustics (PA) as a potential tool to evaluate the effect of mechanical ablation in-vivo, e.g. boiling histotripsy. Two mice bearing a neuroblastoma tumor in the right leg were ablated using an MRI-HIFU system conceived for small animals and monitored using MRI thermometry. High frequency US and PA imaging were performed before and after the HIFU treatment. Afterwards, the tumor was resected for further assessment and evaluation of the ablated region using histopathology. High frequency US imaging revealed the presence of liquefied regions in the treated area together with fragmentized tissue which appeared with different reflecting proprieties compared to the surrounding tissue. Photoacoustic imaging on the other hand revealed the presence of deoxygenated blood within the tumor after the ablation due to the destruction of blood vessel network while color Doppler imaging confirmed the blood vessel network destruction within the tumor. The treated area and the presence of red blood cells detected by photoacoustics were further confirmed by the histopathology. This feasibility study demonstrates the potential of high frequency US and PA approach for assessing in-vivo the effect of mechanical HIFU tumor ablation. PMID:28736668

Image Guidance Technologies for Interventional Pain Procedures: Ultrasound, Fluoroscopy, and CT.

PubMed

Wang, Dajie

2018-01-26

to fluoroscopy. However, further studies are required to prove the efficacy of ultrasound-guided transforaminal epidural injections. SI joint is unique due to its multiplanar orientation, irregular joint gap, partial ankylosis, and thick dorsal and interosseous ligament. Therefore, it can be difficult to access the joint space with fluoroscopic guidance and ultrasound guidance. CT scan, with its cross-sectional images, can identify posterior joint gap, is most likely the best guidance technology for this intervention. Intercostal nerves lie in the subcostal grove close to the plural space. Significant risk of pneumothorax is associated with intercostal blocks. Ultrasound can provide visualization of ribs and pleura. Therefore, it may improve the accuracy of the injection and reduce the risk of pneumothorax. At present time, most pain specialists are familiar with fluoroscopic guidance techniques, and fluoroscopic machines are readily available in the pain clinics. In the contrast, CT guidance can only be performed in specially equipped facilities. Ultrasound machine is generally portable and inexpensive in comparison to CT scanner and fluoroscopic machine. As pain specialists continue to improve their patient care, ultrasound and CT guidance will undoubtedly be incorporated more into the pain management practice. This review is based on a paucity of clinical evidence to compare these guidance technologies; clearly, more clinical studies is needed to further elucidate the pro and cons of each guidance method for various pain management interventions.

Use of a Volume Navigation Technique for Combining Real-Time Ultrasound and Contrast-Enhanced MRI: Accuracy and Feasibility of a Novel Technique for Locating Breast Lesions.

PubMed

Kucukkaya, Fikret; Aribal, Erkin; Tureli, Derya; Altas, Hilal; Kaya, Handan

2016-01-01

The objective of this study was to evaluate the accuracy of the volume navigation technique for combining real-time ultrasound and contrast-enhanced MRI (CE-MRI) of breast lesions. Thirty-eight women with single breast lesions underwent 3-T MRI. A 3.5-minute CE-MRI sequence was used, as was a flexible body coil. Patients underwent imaging in the supine position, with three markers placed on their breasts. Real-time sonographic images were coregistered to the preloaded breast CE-MRI volume by coupling skin markers, with the use of an electromagnetic transmitter positioned next to the subjects. The transmitter detected the spatial positions of the two electromagnetic sensors mounted on the transducer bracket. After this fusion process in 3D space was completed, divergences in the location of the center of each lesion on CE-MRI and ultrasound images were analyzed. The mean lesion size was 17.4 mm on ultrasound and 17.9 mm on MRI, whereas the mean (± SD) misalignment of the lesion centers on CE-MRI and ultrasound was 3.9 ± 2.5 mm on the x-axis (mediolateral view), 3.6 ± 2.7 mm on the y-axis (anteroposterior view), and 4.3 ± 2.6 mm on the z-axis (craniocaudal view). No lesion had a misalignment greater than 10 mm on any of three axes. The accuracy of volume navigation was independent of patient age and the lesion size, location, and histopathologic findings (p > 0.05). Intermediate lesions, which had a depth of center of 11-20 mm on ultrasound had a mean misalignment of 2.6 ± 1.9 mm, compared with 5.5 ± 2.2 mm for deep lesions, which had a depth of center greater than 20 mm (p = 0.049). The volume navigation technique is an accurate method for coregistration of CE-MRI and sonographic images, enabling lesion localization within a limited volume.

Development of a High-Throughput Ultrasound Technique for the Analysis of Tissue Engineering Constructs

PubMed Central

Stukel, Jessica; Goss, Monika; Zhou, Haoyan; Zhou, Wenda; Willits, Rebecca; Exner, Agata A.

2015-01-01

Development of hydrogel-based tissue engineering constructs is growing at a rapid rate, yet translation to patient use has been sluggish. Years of costly preclinical tests are required to predict clinical performance and safety of these devices. The tests are invasive, destructive to the samples and, in many cases, are not representative of the ultimate in vivo scenario. Biomedical imaging has the potential to facilitate biomaterial development by enabling longitudinal noninvasive device characterization directly in situ. Among the various available imaging modalities, ultrasound stands out as an excellent candidate due to low cost, wide availability, and a favorable safety profile. The overall goal of this work was to demonstrate the utility of clinical ultrasound in longitudinal characterization of 3D hydrogel matrices supporting cell growth. Specifically, we developed a quantitative technique using clinical B-mode ultrasound to differentiate collagen content and fibroblast density within poly(ethylene glycol) (PEG) hydrogels and validated it in an in vitro phantom environment. By manipulating the hydrogel gelation, differences in ultrasound signal intensity were found between gels with collagen fibers and those with non-fiber forming collagen, indicating that the technique was sensitive to the configuration of the protein. At a collagen density of 2.5 mg/mL collagen, fiber forming collagen had a significantly increased signal intensity of 14.90± 2.58*10−5 a.u. compared to non-fiber forming intensity at 2.74± 0.36*10−5 a.u. Additionally, differences in intensity were found between living and fixed fibroblasts, with an increased signal intensity detected in living cells (5 ± 0.8*10−5 a.u. in 1 day live cells compared to 2.26 ± 0.39*10−5 a.u. in fixed cells at a concentration of 1*106 cells/mL in gels containing collagen). Overall, there was a linear correlation >0.90 for ultrasound intensity with increasing cell density. Results demonstrate the

Efficient Sample Delay Calculation for 2-D and 3-D Ultrasound Imaging.

PubMed

Ibrahim, Aya; Hager, Pascal A; Bartolini, Andrea; Angiolini, Federico; Arditi, Marcel; Thiran, Jean-Philippe; Benini, Luca; De Micheli, Giovanni

2017-08-01

Ultrasound imaging is a reference medical diagnostic technique, thanks to its blend of versatility, effectiveness, and moderate cost. The core computation of all ultrasound imaging methods is based on simple formulae, except for those required to calculate acoustic propagation delays with high precision and throughput. Unfortunately, advanced three-dimensional (3-D) systems require the calculation or storage of billions of such delay values per frame, which is a challenge. In 2-D systems, this requirement can be four orders of magnitude lower, but efficient computation is still crucial in view of low-power implementations that can be battery-operated, enabling usage in numerous additional scenarios. In this paper, we explore two smart designs of the delay generation function. To quantify their hardware cost, we implement them on FPGA and study their footprint and performance. We evaluate how these architectures scale to different ultrasound applications, from a low-power 2-D system to a next-generation 3-D machine. When using numerical approximations, we demonstrate the ability to generate delay values with sufficient throughput to support 10 000-channel 3-D imaging at up to 30 fps while using 63% of a Virtex 7 FPGA, requiring 24 MB of external memory accessed at about 32 GB/s bandwidth. Alternatively, with similar FPGA occupation, we show an exact calculation method that reaches 24 fps on 1225-channel 3-D imaging and does not require external memory at all. Both designs can be scaled to use a negligible amount of resources for 2-D imaging in low-power applications and for ultrafast 2-D imaging at hundreds of frames per second.

WE-EF-210-08: BEST IN PHYSICS (IMAGING): 3D Prostate Segmentation in Ultrasound Images Using Patch-Based Anatomical Feature

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

Yang, X; Rossi, P; Jani, A

Purpose: Transrectal ultrasound (TRUS) is the standard imaging modality for the image-guided prostate-cancer interventions (e.g., biopsy and brachytherapy) due to its versatility and real-time capability. Accurate segmentation of the prostate plays a key role in biopsy needle placement, treatment planning, and motion monitoring. As ultrasound images have a relatively low signal-to-noise ratio (SNR), automatic segmentation of the prostate is difficult. However, manual segmentation during biopsy or radiation therapy can be time consuming. We are developing an automated method to address this technical challenge. Methods: The proposed segmentation method consists of two major stages: the training stage and the segmentation stage.more » During the training stage, patch-based anatomical features are extracted from the registered training images with patient-specific information, because these training images have been mapped to the new patient’ images, and the more informative anatomical features are selected to train the kernel support vector machine (KSVM). During the segmentation stage, the selected anatomical features are extracted from newly acquired image as the input of the well-trained KSVM and the output of this trained KSVM is the segmented prostate of this patient. Results: This segmentation technique was validated with a clinical study of 10 patients. The accuracy of our approach was assessed using the manual segmentation. The mean volume Dice Overlap Coefficient was 89.7±2.3%, and the average surface distance was 1.52 ± 0.57 mm between our and manual segmentation, which indicate that the automatic segmentation method works well and could be used for 3D ultrasound-guided prostate intervention. Conclusion: We have developed a new prostate segmentation approach based on the optimal feature learning framework, demonstrated its clinical feasibility, and validated its accuracy with manual segmentation (gold standard). This segmentation technique could be a

A single FPGA-based portable ultrasound imaging system for point-of-care applications.

PubMed

Kim, Gi-Duck; Yoon, Changhan; Kye, Sang-Bum; Lee, Youngbae; Kang, Jeeun; Yoo, Yangmo; Song, Tai-kyong

2012-07-01

We present a cost-effective portable ultrasound system based on a single field-programmable gate array (FPGA) for point-of-care applications. In the portable ultrasound system developed, all the ultrasound signal and image processing modules, including an effective 32-channel receive beamformer with pseudo-dynamic focusing, are embedded in an FPGA chip. For overall system control, a mobile processor running Linux at 667 MHz is used. The scan-converted ultrasound image data from the FPGA are directly transferred to the system controller via external direct memory access without a video processing unit. The potable ultrasound system developed can provide real-time B-mode imaging with a maximum frame rate of 30, and it has a battery life of approximately 1.5 h. These results indicate that the single FPGA-based portable ultrasound system developed is able to meet the processing requirements in medical ultrasound imaging while providing improved flexibility for adapting to emerging POC applications.

Imaging of idle breast implants with ultrasound-strain elastography- A first experimental study to establish criteria for accurate imaging of idle implants via ultrasound-strain elastography.

PubMed

Kuehlmann, Britta; Prantl, Lukas; Michael Jung, Ernst

2016-01-01

To investigate whether there are fundamental sonographic and elastographic criteria to precisely assess different surfaces and fillings of idle breast implants and to determine their most distinctive parameters. This was a comparative study of different unused breast implant materials, neighter in animals nor in humans. This knowledge should be transferred in vivo to develop an objective measurement tool. Nine idle breast implants-silicone and polyurethane (PU)-were examined in an experimental study by using ultrasound B-mode with tissue harmonic imaging (THI), speckle reduction imaging (SRI, level 0-4), cross-beam (CB, low, medium, high), photopic and the colour coded ultrasound-strain elastography with a multifrequency probe (9-15 MHz).Using a standardised protocol the implants' centre as well as the edge were analysed by one experienced examiner. Two independent readers performed analysis and evaluation. For image interpretation a score was created (score 0:inadequate image, score 5:best image quality). The highest score result for the centre was achieved by using ultrasound with B-mode in addition with CB level medium, SRI level 2, THI and photopic (mean:3.22±SD:1.56), but without any statistic significant difference (t-value = 0.71). With elastography the implants' edge in general was represented without disruptive artefacts (3.89±0.60) with statistic significant difference (t-value = 5.29). Implants filled with inner cohesive silicone gel II° showed best imaging conditions for their centre via ultrasound (5±0) as well as for their edge via elastography (4.50±0.71). Ultrasound-strain elastography and high resolution ultrasound represent a valuable measurement tool to evaluate different properties of idle breast implants. These modified ultrasound examinations could be an additional help for clinical investigations and be correlated with Baker's Classification.

Ultrasound image-guided therapy enhances antitumor effect of cisplatin.

PubMed

Sasaki, Noboru; Kudo, Nobuki; Nakamura, Kensuke; Lim, Sue Yee; Murakami, Masahiro; Kumara, W R Bandula; Tamura, Yu; Ohta, Hiroshi; Yamasaki, Masahiro; Takiguchi, Mitsuyoshi

2014-01-01

The aim of this study was to clarify whether ultrasound image-guided cisplatin delivery with an intratumor microbubble injection enhances the antitumor effect in a xenograft mouse model. Canine thyroid adenocarcinoma cells were used for all experiments. Before in vivo experiments, the cisplatin and microbubble concentration and ultrasound exposure time were optimized in vitro. For in vivo experiments, cells were implanted into the back of nude mice. Observed by a diagnostic ultrasound machine, a mixture of cisplatin and ultrasound contrast agent, Sonazoid, microbubbles was injected directly into tumors. The amount of injected cisplatin and microbubbles was 1 μg/tumor and 1.2 × 10(7) microbubbles/tumor, respectively, with a total injected volume of 20 μl. Using the same diagnostic machine, tumors were exposed to ultrasound for 15 s. The treatment was repeated four times. The combination of cisplatin, microbubbles, and ultrasound significantly delayed tumor growth as compared with no treatment (after 18 days, 157 ± 55 vs. 398 ± 49 mm(3), P = 0.049). Neither cisplatin alone nor the combination of cisplatin and ultrasound delayed tumor growth. The treatment did not decrease the body weight of mice. Ultrasound image-guided anticancer drug delivery may enhance the antitumor effects of drugs without obvious side effects.

Image-Guided Surgery of Primary Breast Cancer Using Ultrasound Phased Arrays

DTIC Science & Technology

2004-07-01

applications using high-intensity focused ultrasound ( HIFU ). We tems, Once the real-time imaging capability is available for have shown that this dual-mode...Arrays Emad S. Ebbini, PI Introduction High-intensity focus ultrasound ( HIFU ) is gaining wider acceptance in noninvasive or minimally invasive targeting of...Methods in Ultrasound Imaging, ISBI 2004, Arlington, VA, April 2004. III. Yao and Ebbini, "Real-Time Monitoring of the Transients of HIFU -Induced Lesions

Trans-Stent B-Mode Ultrasound and Passive Cavitation Imaging

PubMed Central

Haworth, Kevin J.; Raymond, Jason L.; Radhakrishnan, Kirthi; Moody, Melanie R.; Huang, Shao-Ling; Peng, Tao; Shekhar, Himanshu; Klegerman, Melvin E.; Kim, Hyunggun; Mcpherson, David D.; Holland, Christy K.

2015-01-01

Angioplasty and stenting of a stenosed artery enable acute restoration of blood flow. However, restenosis or a lack of re-endothelization can subsequently occur depending on the stent type. Cavitation-mediated drug delivery is a potential therapy for these conditions, but requires that particular types of cavitation be induced by ultrasound insonation. Because of the heterogeneity of tissue and stochastic nature of cavitation, feedback mechanisms are needed to determine whether the sustained bubble activity is induced. The objective of this study was to determine the feasibility of passive cavitation imaging through a metal stent in a flow phantom and an animal model. In this study, an endovascular stent was deployed in a flow phantom and in porcine femoral arteries. Fluorophore-labeled echogenic liposomes, a theragnostic ultrasound contrast agent, were injected proximal to the stent. Cavitation images were obtained by passively recording and beamforming the acoustic emissions from echogenic liposomes insonified with a low-frequency (500 kHz) transducer. In vitro experiments revealed that the signal-to-noise ratio for detecting stable cavitation activity through the stent was greater than 8 dB. The stent did not significantly reduce the signal-to-noise ratio. Trans-stent cavitation activity was also detected in vivo via passive cavitation imaging when echogenic liposomes were insonified by the 500-kHz transducer. When stable cavitation was detected, delivery of the fluorophore into the arterial wall was observed. Increased echogenicity within the stent was also observed when echogenic liposomes were administered. Thus, both B-mode ultrasound imaging and cavitation imaging are feasible in the presence of an endovascular stent in vivo. Demonstration of this capability supports future studies to monitor restenosis with contrast-enhanced ultrasound and pursue image-guided ultrasound-mediated drug delivery to inhibit restenosis. PMID:26547633

Feasibility of imaging superficial palmar arch using micro-ultrasound, 7T and 3T magnetic resonance imaging.

PubMed

Pruzan, Alison N; Kaufman, Audrey E; Calcagno, Claudia; Zhou, Yu; Fayad, Zahi A; Mani, Venkatesh

2017-02-28

To demonstrate feasibility of vessel wall imaging of the superficial palmar arch using high frequency micro-ultrasound, 7T and 3T magnetic resonance imaging (MRI). Four subjects (ages 22-50 years) were scanned on a micro-ultrasound system with a 45-MHz transducer (Vevo 2100, VisualSonics). Subjects' hands were then imaged on a 3T clinical MR scanner (Siemens Biograph MMR) using an 8-channel special purpose phased array carotid coil. Lastly, subjects' hands were imaged on a 7T clinical MR scanner (Siemens Magnetom 7T Whole Body Scanner) using a custom built 8-channel transmit receive carotid coil. All three imaging modalities were subjectively analyzed for image quality and visualization of the vessel wall. Results of this very preliminary study indicated that vessel wall imaging of the superficial palmar arch was feasible with a whole body 7T and 3T MRI in comparison with micro-ultrasound. Subjective analysis of image quality (1-5 scale, 1: poorest, 5: best) from B mode, ultrasound, 3T SPACE MRI and 7T SPACE MRI indicated that the image quality obtained at 7T was superior to both 3T MRI and micro-ultrasound. The 3D SPACE sequence at both 7T and 3T MRI with isotropic voxels allowed for multi-planar reformatting of images and allowed for less operator dependent results as compared to high frequency micro-ultrasound imaging. Although quantitative analysis revealed that there was no significant difference between the three methods, the 7T Tesla trended to have better visibility of the vessel and its wall. Imaging of smaller arteries at the 7T is feasible for evaluating atherosclerosis burden and may be of clinical relevance in multiple diseases.

Co-registered Frequency-Domain Photoacoustic Radar and Ultrasound System for Subsurface Imaging in Turbid Media

NASA Astrophysics Data System (ADS)

Dovlo, Edem; Lashkari, Bahman; Mandelis, Andreas

2016-03-01

Frequency-domain photoacoustic radar (FD-PAR) imaging of absorbers in turbid media and their comparison and/or validation as well as co-registration with their corresponding ultrasound (US) images are demonstrated in this paper. Also presented are the FD-PAR tomography and the effects of reducing the number of scan lines (or angles) on image quality, resolution, and contrast. The FD-PAR modality uses intensity-modulated (coded) continuous wave laser sources driven by frequency-swept (chirp) waveforms. The spatial cross-correlation function between the PA response and the reference signal used for laser source modulation produces the reconstructed image. Live animal testing is demonstrated, and images of comparable signal-to-noise ratio, contrast, and spatial resolution were obtained. Various image improvement techniques to further reduce absorber spread and artifacts in the images such as normalization, filtering, and amplification were also investigated. The co-registered image produced from the combined US and PA images provides more information than both images independently. The significance of this work lies in the fact that achieving PA imaging functionality on a commercial ultrasound instrument could accelerate its clinical acceptance and use. This work is aimed at functional PA imaging of small animals in vivo.

Refining enamel thickness measurements from B-mode ultrasound images.

PubMed

Hua, Jeremy; Chen, Ssu-Kuang; Kim, Yongmin

2009-01-01

Dental erosion has been growing increasingly prevalent with the rise in consumption of heavy starches, sugars, coffee, and acidic beverages. In addition, various disorders, such as Gastroenterological Reflux Disease (GERD), have symptoms of rapid rates of tooth erosion. The measurement of enamel thickness would be important for dentists to assess the progression of enamel loss from all forms of erosion, attrition, and abrasion. Characterizing enamel loss is currently done with various subjective indexes that can be interpreted in different ways by different dentists. Ultrasound has been utilized since the 1960s to determine internal tooth structure, but with mixed results. Via image processing and enhancement, we were able to refine B-mode dental ultrasound images for more accurate enamel thickness measurements. The mean difference between the measured thickness of the occlusal enamel from ultrasound images and corresponding gold standard CT images improved from 0.55 mm to 0.32 mm with image processing (p = 0.033). The difference also improved from 0.62 to 0.53 mm at the buccal/lingual enamel surfaces, but not significantly (p = 0.38).

Ultrafast Ultrasound Imaging of Ocular Anatomy and Blood Flow

PubMed Central

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

2016-01-01

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

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

PubMed

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

2009-03-01

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

Delay and Standard Deviation Beamforming to Enhance Specular Reflections in Ultrasound Imaging.

PubMed

Bandaru, Raja Sekhar; Sornes, Anders Rasmus; Hermans, Jeroen; Samset, Eigil; D'hooge, Jan

2016-12-01

Although interventional devices, such as needles, guide wires, and catheters, are best visualized by X-ray, real-time volumetric echography could offer an attractive alternative as it avoids ionizing radiation; it provides good soft tissue contrast, and it is mobile and relatively cheap. Unfortunately, as echography is traditionally used to image soft tissue and blood flow, the appearance of interventional devices in conventional ultrasound images remains relatively poor, which is a major obstacle toward ultrasound-guided interventions. The objective of this paper was therefore to enhance the appearance of interventional devices in ultrasound images. Thereto, a modified ultrasound beamforming process using conventional-focused transmit beams is proposed that exploits the properties of received signals containing specular reflections (as arising from these devices). This new beamforming approach referred to as delay and standard deviation beamforming (DASD) was quantitatively tested using simulated as well as experimental data using a linear array transducer. Furthermore, the influence of different imaging settings (i.e., transmit focus, imaging depth, and scan angle) on the obtained image contrast was evaluated. The study showed that the image contrast of specular regions improved by 5-30 dB using DASD beamforming compared with traditional delay and sum (DAS) beamforming. The highest gain in contrast was observed when the interventional device was tilted away from being orthogonal to the transmit beam, which is a major limitation in standard DAS imaging. As such, the proposed beamforming methodology can offer an improved visualization of interventional devices in the ultrasound image with potential implications for ultrasound-guided interventions.

Automatic measurement of pennation angle and fascicle length of gastrocnemius muscles using real-time ultrasound imaging.

PubMed

Zhou, Guang-Quan; Chan, Phoebe; Zheng, Yong-Ping

2015-03-01

Muscle imaging is a promising field of research to understand the biological and bioelectrical characteristics of muscles through the observation of muscle architectural change. Sonomyography (SMG) is a technique which can quantify the real-time architectural change of muscles under different contractions and motions with ultrasound imaging. The pennation angle and fascicle length are two crucial SMG parameters to understand the contraction mechanics at muscle level, but they have to be manually detected on ultrasound images frame by frame. In this study, we proposed an automatic method to quantitatively identify pennation angle and fascicle length of gastrocnemius (GM) muscle based on multi-resolution analysis and line feature extraction, which could overcome the limitations of tedious and time-consuming manual measurement. The method started with convolving Gabor wavelet specially designed for enhancing the line-like structure detection in GM ultrasound image. The resulting image was then used to detect the fascicles and aponeuroses for calculating the pennation angle and fascicle length with the consideration of their distribution in ultrasound image. The performance of this method was tested on computer simulated images and experimental images in vivo obtained from normal subjects. Tests on synthetic images showed that the method could identify the fascicle orientation with an average error less than 0.1°. The result of in vivo experiment showed a good agreement between the results obtained by the automatic and the manual measurements (r=0.94±0.03; p<0.001, and r=0.95±0.02, p<0.001). Furthermore, a significant correlation between the ankle angle and pennation angle (r=0.89±0.05; p<0.001) and fascicle length (r=-0.90±0.04; p<0.001) was found for the ankle plantar flexion. This study demonstrated that the proposed method was able to automatically measure the pennation angle and fascicle length of GM ultrasound images, which made it feasible to investigate

Comb-push Ultrasound Shear Elastography (CUSE): A Novel Method for Two-dimensional Shear Elasticity Imaging of Soft Tissues

PubMed Central

Song, Pengfei; Zhao, Heng; Manduca, Armando; Urban, Matthew W.; Greenleaf, James F.; Chen, Shigao

2012-01-01

Fast and accurate tissue elasticity imaging is essential in studying dynamic tissue mechanical properties. Various ultrasound shear elasticity imaging techniques have been developed in the last two decades. However, to reconstruct a full field-of-view 2D shear elasticity map, multiple data acquisitions are typically required. In this paper, a novel shear elasticity imaging technique, comb-push ultrasound shear elastography (CUSE), is introduced in which only one rapid data acquisition (less than 35 ms) is needed to reconstruct a full field-of-view 2D shear wave speed map (40 mm × 38 mm). Multiple unfocused ultrasound beams arranged in a comb pattern (comb-push) are used to generate shear waves. A directional filter is then applied upon the shear wave field to extract the left-to-right (LR) and right-to-left (RL) propagating shear waves. Local shear wave speed is recovered using a time-of-flight method based on both LR and RL waves. Finally a 2D shear wave speed map is reconstructed by combining the LR and RL speed maps. Smooth and accurate shear wave speed maps are reconstructed using the proposed CUSE method in two calibrated homogeneous phantoms with different moduli. Inclusion phantom experiments demonstrate that CUSE is capable of providing good contrast (contrast-to-noise-ratio ≥ 25 dB) between the inclusion and background without artifacts and is insensitive to inclusion positions. Safety measurements demonstrate that all regulated parameters of the ultrasound output level used in CUSE sequence are well below the FDA limits for diagnostic ultrasound. PMID:22736690

A novel dual-frequency imaging method for intravascular ultrasound applications.

PubMed

Qiu, Weibao; Chen, Yan; Wong, Chi-Man; Liu, Baoqiang; Dai, Jiyan; Zheng, Hairong

2015-03-01

Intravascular ultrasound (IVUS), which is able to delineate internal structures of vessel wall with fine spatial resolution, has greatly enriched the knowledge of coronary atherosclerosis. A novel dual-frequency imaging method is proposed in this paper for intravascular imaging applications. A probe combined two ultrasonic transducer elements with different center frequencies (36 MHz and 78 MHz) is designed and fabricated with PMN-PT single crystal material. It has the ability to balance both imaging depth and resolution, which are important imaging parameters for clinical test. A dual-channel imaging platform is also proposed for real-time imaging, and this platform has been proven to support programmable processing algorithms, flexible imaging control, and raw RF data acquisition for IVUS applications. Testing results show that the -6 dB axial and lateral imaging resolutions of low-frequency ultrasound are 78 and 132 μm, respectively. In terms of high-frequency ultrasound, axial and lateral resolutions are determined to be as high as 34 and 106 μm. In vitro intravascular imaging on healthy swine aorta is conducted to demonstrate the performance of the dual-frequency imaging method for IVUS applications. Copyright © 2014 Elsevier B.V. All rights reserved.

An Assessment of Iterative Reconstruction Methods for Sparse Ultrasound Imaging

PubMed Central

Valente, Solivan A.; Zibetti, Marcelo V. W.; Pipa, Daniel R.; Maia, Joaquim M.; Schneider, Fabio K.

2017-01-01

Ultrasonic image reconstruction using inverse problems has recently appeared as an alternative to enhance ultrasound imaging over beamforming methods. This approach depends on the accuracy of the acquisition model used to represent transducers, reflectivity, and medium physics. Iterative methods, well known in general sparse signal reconstruction, are also suited for imaging. In this paper, a discrete acquisition model is assessed by solving a linear system of equations by an ℓ1-regularized least-squares minimization, where the solution sparsity may be adjusted as desired. The paper surveys 11 variants of four well-known algorithms for sparse reconstruction, and assesses their optimization parameters with the goal of finding the best approach for iterative ultrasound imaging. The strategy for the model evaluation consists of using two distinct datasets. We first generate data from a synthetic phantom that mimics real targets inside a professional ultrasound phantom device. This dataset is contaminated with Gaussian noise with an estimated SNR, and all methods are assessed by their resulting images and performances. The model and methods are then assessed with real data collected by a research ultrasound platform when scanning the same phantom device, and results are compared with beamforming. A distinct real dataset is finally used to further validate the proposed modeling. Although high computational effort is required by iterative methods, results show that the discrete model may lead to images closer to ground-truth than traditional beamforming. However, computing capabilities of current platforms need to evolve before frame rates currently delivered by ultrasound equipments are achievable. PMID:28282862

Ultrasound imaging beyond the vasculature with new generation contrast agents.

PubMed

Perera, Reshani H; Hernandez, Christopher; Zhou, Haoyan; Kota, Pavan; Burke, Alan; Exner, Agata A

2015-01-01

Current commercially available ultrasound contrast agents are gas-filled, lipid- or protein-stabilized microbubbles larger than 1 µm in diameter. Because the signal generated by these agents is highly dependent on their size, small yet highly echogenic particles have been historically difficult to produce. This has limited the molecular imaging applications of ultrasound to the blood pool. In the area of cancer imaging, microbubble applications have been constrained to imaging molecular signatures of tumor vasculature and drug delivery enabled by ultrasound-modulated bubble destruction. Recently, with the rise of sophisticated advancements in nanomedicine, ultrasound contrast agents, which are an order of magnitude smaller (100-500 nm) than their currently utilized counterparts, have been undergoing rapid development. These agents are poised to greatly expand the capabilities of ultrasound in the field of targeted cancer detection and therapy by taking advantage of the enhanced permeability and retention phenomenon of many tumors and can extravasate beyond the leaky tumor vasculature. Agent extravasation facilitates highly sensitive detection of cell surface or microenvironment biomarkers, which could advance early cancer detection. Likewise, when combined with appropriate therapeutic agents and ultrasound-mediated deployment on demand, directly at the tumor site, these nanoparticles have been shown to contribute to improved therapeutic outcomes. Ultrasound's safety profile, broad accessibility and relatively low cost make it an ideal modality for the changing face of healthcare today. Aided by the multifaceted nano-sized contrast agents and targeted theranostic moieties described herein, ultrasound can considerably broaden its reach in future applications focused on the diagnosis and staging of cancer. © 2015 Wiley Periodicals, Inc.

Ultrasound Imaging Beyond the Vasculature with New Generation Contrast Agents

PubMed Central

Perera, Reshani H.; Hernandez, Christopher; Zhou, Haoyan; Kota, Pavan; Burke, Alan

2015-01-01

Current commercially available ultrasound contrast agents are gas-filled, lipid- or protein-stabilized microbubbles larger than 1 μm in diameter. Because the signal generated by these agents is highly dependent on their size, small yet highly echogenic particles have been historically difficult to produce. This has limited the molecular imaging applications of ultrasound to the blood pool. In the area of cancer imaging, microbubble applications have been constrained to imaging molecular signatures of tumor vasculature and drug delivery enabled by ultrasound-modulated bubble destruction. Recently, with the rise of sophisticated advancements in nanomedicine, ultrasound contrast agents, which are an order of magnitude smaller (100-500 nm) than their currently utilized counterparts, have been undergoing rapid development. These agents are poised to greatly expand the capabilities of ultrasound in the field of targeted cancer detection and therapy by taking advantage of the enhanced permeability and retention phenomenon of many tumors and can extravasate beyond the leaky tumor vasculature. Agent extravasation facilitates highly sensitive detection of cell surface or microenvironment biomarkers, which could advance early cancer detection. Likewise, when combined with appropriate therapeutic agents and ultrasound-mediated deployment on demand, directly at the tumor site, these nanoparticles have been shown to contribute to improved therapeutic outcomes. Ultrasound's safety profile, broad accessibility and relatively low cost make it an ideal modality for the changing face of healthcare today. Aided by the multifaceted nano-sized contrast agents and targeted theranostic moieties described herein, ultrasound can considerably broaden its reach in future applications focused on the diagnosis and staging of cancer. PMID:25580914

Transvaginal 3D Image-Guided High Intensity Focused Ultrasound Array

NASA Astrophysics Data System (ADS)

Held, Robert; Nguyen, Thuc Nghi; Vaezy, Shahram

2005-03-01

The goal of this project is to develop a transvaginal image-guided High Intensity Focused Ultrasound (HIFU) device using piezocomposite HIFU array technology, and commercially-available ultrasound imaging. Potential applications include treatment of uterine fibroids and abnormal uterine bleeding. The HIFU transducer was an annular phased array, with a focal length range of 30-60 mm, an elliptically-shaped aperture of 35×60 mm, and an operating frequency of 3 MHz. A pillow-shaped bag with water circulation will be used for coupling the HIFU energy into the tissue. An intra-cavity imaging probe (C9-5, Philips) was integrated with the HIFU array such that the focal axis of the HIFU transducer was within the image plane. The entire device will be covered by a gel-filled condom when inserted in the vaginal cavity. To control it, software packages were developed in the LabView programming environment. An imaging algorithm processed the ultrasound image to remove noise patterns due to the HIFU signal. The device will be equipped with a three-dimensional tracking system, using a six-degrees-of-freedom articulating arm. Necrotic lesions were produced in a tissue-mimicking phantom and a turkey breast sample for all focal lengths. Various HIFU doses allow various necrotic lesion shapes, including thin ellipsoidal, spherical, wide cylindrical, and teardrop-shaped. Software control of the device allows multiple foci to be activated sequentially for desired lesion patterns. Ultrasound imaging synchronization can be achieved using hardware signals obtained from the imaging system, or software signals determined empirically for various imaging probes. The image-guided HIFU device will provide a valuable tool in visualization of uterine fibroid tumors for the purposes of planning and subsequent HIFU treatment of the tumor, all in a 3D environment. The control system allows for various lesions of different shapes to be optimally positioned in the tumor to cover the entire tumor

Double-scattering/reflection in a Single Nanoparticle for Intensified Ultrasound Imaging

PubMed Central

Zhang, Kun; Chen, Hangrong; Guo, Xiasheng; Zhang, Dong; Zheng, Yuanyi; Zheng, Hairong; Shi, Jianlin

2015-01-01

Ultrasound contrast agents (UCAs) designed by the conventional composition-based strategy, often suffer from relatively low ultrasound utilization efficiency. In this report, a structure-based design concept of double-scattering/reflection in a single nanoparticle for enhancing ultrasound imaging has been proposed. To exemplify this concept, a rattle-type mesoporous silica nanostructure (MSN) with two contributing interfaces has been employed as the ideal model. Contributed by double-scattering/reflection interfaces, the rattle-type MSN, as expected, performs much better in in vitro and in vivo ultrasound imaging than the other two nanostructures (solid and hollow) containing only one scattering/reflection interface. More convincingly, related acoustic measurements and simulation calculations also confirm this design concept. Noticeably, the rattle-type MSN has also been demonstrated capable of improving intracellular ultrasound molecular imaging. As a universal method, the structure-design concept can extend to guide the design of new generation UCAs with many other compositions and similar structures (e.g., heterogeneous rattle-type, double-shelled). PMID:25739832

Double-scattering/reflection in a single nanoparticle for intensified ultrasound imaging.

PubMed

Zhang, Kun; Chen, Hangrong; Guo, Xiasheng; Zhang, Dong; Zheng, Yuanyi; Zheng, Hairong; Shi, Jianlin

2015-03-05

Ultrasound contrast agents (UCAs) designed by the conventional composition-based strategy, often suffer from relatively low ultrasound utilization efficiency. In this report, a structure-based design concept of double-scattering/reflection in a single nanoparticle for enhancing ultrasound imaging has been proposed. To exemplify this concept, a rattle-type mesoporous silica nanostructure (MSN) with two contributing interfaces has been employed as the ideal model. Contributed by double-scattering/reflection interfaces, the rattle-type MSN, as expected, performs much better in in vitro and in vivo ultrasound imaging than the other two nanostructures (solid and hollow) containing only one scattering/reflection interface. More convincingly, related acoustic measurements and simulation calculations also confirm this design concept. Noticeably, the rattle-type MSN has also been demonstrated capable of improving intracellular ultrasound molecular imaging. As a universal method, the structure-design concept can extend to guide the design of new generation UCAs with many other compositions and similar structures (e.g., heterogeneous rattle-type, double-shelled).