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1

Tissue Characterization with Ultrasound.  

National Technical Information Service (NTIS)

The purpose of this research is to establish noninvasive tissue characterization with ultrasound by adapting the concepts used in x-ray diffraction and atmospheric probing with radar. The initial period of the research included: (1) hardware acquisition a...

R. C. Waag

1976-01-01

2

Effect of Ultrasound on Tissue-Type Plasminogen Activator-Induced Thrombolysis. (Reannouncement with New Availability Information).  

National Technical Information Service (NTIS)

The efficacy of fibrinolytic therapy is limited by the small surface area of the clot that is available for the binding of the thrombolytic agent, such as tissue-type plasminogen activator (t-PA). We hypothesized that exposure of the clot to ultrasound du...

C. G. Lauer R. Burge D. B. Tang B. G. Bass E. R. Gomez

1992-01-01

3

Ultrasound tissue analysis and characterization  

NASA Astrophysics Data System (ADS)

On the battlefield of the future, it may become feasible for medics to perform, via application of new biomedical technologies, more sophisticated diagnoses and surgery than is currently practiced. Emerging biomedical technology may enable the medic to perform laparoscopic surgical procedures to remove, for example, shrapnel from injured soldiers. Battlefield conditions constrain the types of medical image acquisition and interpretation which can be performed. Ultrasound is the only viable biomedical imaging modality appropriate for deployment on the battlefield -- which leads to image interpretation issues because of the poor quality of ultrasound imagery. To help overcome these issues, we develop and implement a method of image enhancement which could aid non-experts in the rapid interpretation and use of ultrasound imagery. We describe an energy minimization approach to finding boundaries in medical images and show how prior information on edge orientation can be incorporated into this framework to detect tissue boundaries oriented at a known angle.

Kaufhold, John; Chan, Ray; Karl, William C.; Castanon, David A.

1999-07-01

4

The sensitivity of biological tissue to ultrasound  

Microsoft Academic Search

Mammalian tissues have differing sensitivities to damage by physical agents such as ultrasound. This article evaluates the scientific data in terms of known physical mechanisms of interaction and the impact on pre- and postnatal tissues. Actively dividing cells of the embryonic and fetal central nervous system are most readily disturbed. As a diagnostic ultrasound beam envelopes a small volume of

Stanley B. Barnett; Hans-Dieter Rott; Gail R. ter Haar; Marvin C. Ziskin; Kazuo Maeda

1997-01-01

5

Ultrasound image segmentation and tissue characterization.  

PubMed

Ultrasound image segmentation deals with delineating the boundaries of structures, as a step towards semi-automated or fully automated measurement of dimensions or for characterizing tissue regions. Ultrasound tissue characterization (UTC) is driven by knowledge of the physics of ultrasound and its interactions with biological tissue, and has traditionally used signal modelling and analysis to characterize and differentiate between healthy and diseased tissue. Thus, both aim to enhance the capabilities of ultrasound as a quantitative tool in clinical medicine, and the two end goals can be the same, namely to characterize the health of tissue. This article reviews both research topics, and finds that the two fields are becoming more tightly coupled, even though there are key challenges to overcome in each area, influenced by factors such as more open software-based ultrasound system architectures, increased computational power, and advances in imaging transducer design. PMID:20349821

Noble, J A

2010-01-01

6

Stimulation of Tissue Healing by Ultrasound: Physical Mechanisms of Action  

NASA Astrophysics Data System (ADS)

Even though the use of ultrasound in medicine is better known by its results in diagnostic procedures, the employ of this type of mechanical energy with therapeutic purposes is been used in new and impressive applications. To obtain or to improve tissue healing in many ailments it is used a lot of approaches, from the employ of antibiotics when it is considered by the presence of an infection in the wound, to several types of physical stimulation. One of them is ultrasound. This paper consider some of the most important mechanisms of action of ultrasound in tissue that can be related whit the repair processes and specifies levels of activation of many paths of action. Especial emphasis has received the stimulation of bone repair by ultrasound.

Rodríguez, O.; Chong, J.; Monreal, R.

2004-09-01

7

Challenges in tissue characterization from backscattered intravascular ultrasound signals  

NASA Astrophysics Data System (ADS)

Plaque characterization through backscattered intravascular ultrasound (IVUS) signal analysis has been the subject of extensive study for the past several years. A number of algorithms to analyze IVUS images and underlying RF signals to delineate the composition of atherosclerotic plaque have been reported. In this paper, we present several realistic challenges one faces throughout the process of developing such algorithms to characterize tissue type. The basic tenet of ultrasound tissue characterization is that different tissue types imprint their own "signature" on the backscattered echo returning to the transducer. Tissue characterization is possible to the extent that these echo signals can be received, the signatures read, and uniquely attributed to a tissue type. The principal difficulty in doing tissue characterization is that backscattered RF signals originating as echoes from different groups of cells of the same tissue type exhibit no obvious commonality in appearance in the time domain. This happens even in carefully controlled laboratory experiments. We describe the method of acquisition and digitization of ultrasound radiofrequency (RF) signals from left anterior descending and left circumflex coronary arteries. The challenge of obtaining corresponding histology images to match to specific regions-of-interest on the images is discussed. A tissue characterization technique based on seven features is compared to a full spectrum based approach. The same RF and histology data sets were used to evaluate the performances of these two techniques.

Katouzian, Amin; Sathyanarayana, Shashidhar; Li, Wenguang; Thomas, Tom; Carlier, Stéphane G.

2007-03-01

8

Ultrasound-targeted transfection of tissue-type plasminogen activator gene carried by albumin nanoparticles to dog myocardium to prevent thrombosis after heart mechanical valve replacement  

PubMed Central

Background There are more than 300,000 prosthetic heart valve replacements each year worldwide. These patients are faced with a higher risk of thromboembolic events after heart valve surgery and long-term or even life-long anticoagulative and antiplatelet therapies are necessary. Some severe complications such as hemorrhaging or rebound thrombosis can occur when the therapy ceases. Tissue-type plasminogen activator (t-PA) is a thrombolytic agent. One of the best strategies is gene therapy, which offers a local high expression of t-PA over a prolonged time period to avoid both systemic hemorrhaging and local rebound thrombosis. There are some issues with t-PA that need to be addressed: currently, there is no up-to-date report on how the t-PA gene targets the heart in vivo and the gene vector for t-PA needs to be determined. Aims To fabricate an albumin nano-t-PA gene ultrasound-targeted agent and investigate its targeting effect on prevention of thrombosis after heart mechanic valve replacement under therapeutic ultrasound. Methods A dog model of mechanical tricuspid valve replacement was constructed. A highly expressive t-PA gene plasmid was constructed and packaged by nanoparticles prepared with bovine serum albumin. This nanopackaged t-PA gene plasmid was further cross-linked to ultrasonic microbubbles prepared with sucrose and bovine serum albumin to form the ultrasonic-targeted agent for t-PA gene transfection. The agent was given intravenously followed by a therapeutic ultrasound treatment (1 MHz, 1.5 w/cm2, 10 minutes) of the heart soon after valve replacement had been performed. The expression of t-PA in myocardium was detected with multiclonal antibodies to t-PA by the indirect immunohistochemical method. Venous blood t-PA and D-dimer contents were tested before and 1, 2, 4, and 8 weeks after the operation. Results The high expression of t-PA could be seen in myocardium with increases in blood t-PA and D-dimer contents and thrombosis was prevented 8 weeks after operation. Conclusion We successfully fabricated an albumin nano-t-PA gene ultrasound-targeted agent that could prevent dog thrombosis after mechanical heart valve replacement. Our study provides an experimental basis for prevention of human thrombosis-related diseases.

Ji, Jun; Ji, Shang-Yi; Yang, Jian-An; He, Xia; Yang, Xiao-Han; Ling, Wen-Ping; Chen, Xiao-Ling

2012-01-01

9

Tissue mimicking materials for dental ultrasound  

PubMed Central

While acoustic tissue mimicking materials have been explored for a variety of soft and hard biological tissues, no dental hard tissue mimicking materials have been characterized. Tooth phantoms are necessary to better understand acoustic phenomenology within the tooth environment and to accelerate the advancement of dental ultrasound imaging systems. In this study, soda lime glass and dental composite were explored as surrogates for human enamel and dentin, respectively, in terms of compressional velocity, attenuation, and acoustic impedance. The results suggest that a tooth phantom consisting of glass and composite can effectively mimic the acoustic behavior of a natural human tooth.

Singh, Rahul S.; Culjat, Martin O.; Grundfest, Warren S.; Brown, Elliott R.; White, Shane N.

2008-01-01

10

Fuzzy similarity measures for ultrasound tissue characterization  

NASA Astrophysics Data System (ADS)

Computerized ultrasound tissue characterization has become an objective means for diagnosis of diseases. It is difficult to differentiate diffuse liver diseases, namely cirrhotic and fatty liver from a normal one, by visual inspection from the ultrasound images. The visual criteria for differentiating diffused diseases is rather confusing and highly dependent upon the sonographer's experience. The need for computerized tissue characterization is thus justified to quantitatively assist the sonographer for accurate differentiation and to minimize the degree of risk from erroneous interpretation. In this paper we used the fuzzy similarity measure as an approximate reasoning technique to find the maximum degree of matching between an unknown case defined by a feature vector and a family of prototypes (knowledge base). The feature vector used for the matching process contains 8 quantitative parameters (textural, acoustical, and speckle parameters) extracted from the ultrasound image. The steps done to match an unknown case with the family of prototypes (cirr, fatty, normal) are: Choosing the membership functions for each parameter, then obtaining the fuzzification matrix for the unknown case and the family of prototypes, then by the linguistic evaluation of two fuzzy quantities we obtain the similarity matrix, then by a simple aggregation method and the fuzzy integrals we obtain the degree of similarity. Finally, we find that the similarity measure results are comparable to the neural network classification techniques and it can be used in medical diagnosis to determine the pathology of the liver and to monitor the extent of the disease.

Emara, Salem M.; Badawi, Ahmed M.; Youssef, Abou-Bakr M.

1995-03-01

11

Nonlinear absorption in biological tissue for high intensity focused ultrasound  

Microsoft Academic Search

In recent years the propagation of the high intensity focused ultrasound (HIFU) in biological tissue is an interesting area due to its potential applications in non-invasive treatment of disease. The base principle of these applications is the heat effect generated by ultrasound absorption. In order to control therapeutic efficiency, it is important to evaluate the heat generation in biological tissue

Xiaozhou Liu; Junlun Li; Xiufen Gong; Dong Zhang

2006-01-01

12

High-resolution quantitative ultrasound imaging for soft tissue classification  

Microsoft Academic Search

Mouse models have been widely used in cardiovascular research when investigating the progression or treatment of various diseases. It is always challenging to find non-invasive tools for early detection of diseases. This led us to the development of small animal models for diagnostic imaging techniques, such as high-frequency quantitative ultrasound imaging. This work describes the development of an ultrasound tissue

Ahmed M. Mahmoud; Osama M. Mukdadi; Bunyen Teng; S. Jamal Mustafa

2011-01-01

13

Impedance estimation of soft tissue using ultrasound signal.  

PubMed

This paper proposes a new impedance estimation method for soft tissue using ultrasound. This method estimates the impedance distribution inside an object. An ultrasound probe, which is attached to a force sensor, compresses soft tissue and observes the deformation process of tissue while measuring reaction force. The impedance parameters are then estimated based on this information. Experiments were conducted under two conditions, a static analysis and a dynamic analysis. In the static analysis, the ultrasound probe compressed the soft tissue slowly while keeping a balance of the power. In the dynamic analysis, the probe compressed tissue dynamically, and the deformation process of the soft tissue was observed. Experimental results demonstrated that our method can estimate the impedance of a soft object. PMID:18002767

Fukuda, Osamu; Tsubai, Masayoshi; Ueno, Naohiro

2007-01-01

14

Drug Delivery to Extravascular Tissue by Ultrasound-activated Microbubbles  

NASA Astrophysics Data System (ADS)

Drugs will be delivered to tissue more efficiently if the vascular endothelial permeability is increased. Although recent studies have established that the permeability of single-cell membranes is increased by ultrasound in combination with contrast agents, it is not known whether this combination can also increase the permeability of an endothelial layer. To investigate endothelial layer permeability, we treated monolayers of human umbilical vein endothelial cells with ultrasound and the contrast agent BR14. Endothelial layer permeability was assessed by measuring the transendothelial electrical resistance (TEER) and the transendothelial transport of fluorescein. Ultrasound in combination with BR14 significantly decreased TEER to 68.0 +/- 3.1% of initial values and temporally increased endothelial permeability for fluorescein by 38.1 +/- 16.4 %. After treatment, no cell loss or damage was observed. In conclusion, ultrasound in combination with BR14 increased the endothelial layer permeability. This feature may be used for future ultrasound-guided drug delivery systems.

Kooiman, Klazina; Harteveld, Miranda; de Jong, Nico; van Wamel, Annemieke

2007-05-01

15

Therapeutic Ultrasound Enhancement of Drug Delivery to Soft Tissues  

Microsoft Academic Search

Effects of exposure to 1.58 MHz focused ultrasound on transport of Evans Blue Dye (EBD) in soft tissues are investigated when an external pressure gradient is applied to induce convective flow through the tissue. The magnitude of the external pressure gradient is chosen to simulate conditions in brain parenchyma during convection-enhanced drug delivery (CED) to the brain. EBD uptake and

George Lewis; William Olbricht

2009-01-01

16

Modeling Heat Transfer in Tissue for Therapeutic Ultrasound  

NASA Astrophysics Data System (ADS)

Hyperthermia treatment planning (HTP) is becoming available for individual patients. The components of a HTP system have been described. As an example for the application of HTP in therapeutic ultrasound the temperature distribution in a bovine tongue, heated with a scanning ultrasound focus, is calculated using the Discrete VAsculature (DIVA) thermal model. This model is capable to describe the individual thermal behavior of the discrete blood vessels. Simulations show the overall temperature heterogeneity and the severe thermal underdosage of the tissue around large passing vessels. This implies that in the application of therapeutic ultrasound for malignant tumors great care must be taken.

Lagendijk, Jan J. W.; Raaymakers, Bas W.

2006-05-01

17

Phased array ultrasound imaging through planar tissue layers.  

PubMed

Conventional ultrasound imaging devices are designed based on the assumption of a homogeneous tissue medium of constant acoustic velocity = 1540 m/sec. However, the body consists of tissue layers of varying thicknesses and velocities which range from 1470 m/sec in fat to 3200 m/sec in skull bone. Refraction effects from these layers degrade ultrasound image quality. In this paper, pulse-echo ultrasound imaging is modeled as imaging an organ of interest through an intervening planar tissue layer, such as liver through fat in the abdomen or brain through skull bone in the adult head. Refraction effects from planar tissue layer interfaces are analyzed using Snell's law and measured using phantoms. We also introduce an on-line phased array correction technique based on planar tissue layers to restore ultrasound image quality. We conclude that fat/organ planar interfaces do not degrade image quality significantly. However, refraction effects at a skull/brain planar interface degrades resolution and target acquisition and introduces geometric distortion. Our plane layer phased array correction technique significantly improves image quality in phantoms through lucite aberrators and improves adult cephalic ultrasound image quality when used through the top of the adult skull. The correction technique is robust even in the presence of inaccurate estimates of skull thickness. PMID:3962008

Smith, S W; Trahey, G E; von Ramm, O T

1986-03-01

18

Fluorescence tomography of biological tissue based on ultrasound tagging technique  

NASA Astrophysics Data System (ADS)

We report a study for the development of tomographic imaging technique of fluorescence in biological tissue for assays of biological function. Ultrasonic modulation of light based on the acousto-optic effect (so called ultrasound 'tagging') is applied for imaging of fluorescence distribution in the light-scattering media. Sound-field characteristics that affect the light by modulating its amplitude through variation of the refractive index in the medium were determined. With using focused ultrasound, selectively modulated fluorescence on a depth-axis of the medium can be detected. Ultrasound tagging technique applied measuring the optical absorption in light scattering media is well known, and it is principally based on the modulation of speckle pattern. On the contrary, in the case of fluorescence, displacement of scattering particles and variation of the refractive index that is induced by density distribution in a sound field might produce the intensity modulation of scattered light. We have experimentally shown that ultrasound tagging technique is also available for fluorescence measurement. In this paper, we demonstrate the result of tomographic images of fluorescence in dense scattering media using porcine muscle as a biological tissue, and bovine adipose. Tissue samples had the dimension of 40 x 40 mm in section and fluorophore which had the 3mm size was embedded in the center of the tissue. The localized image of the fluorophore was determined with the spatial resolution of focus size of the ultrasound, suggesting the applicability of this technique for visualization of fluorescent probes in deep portion of living body.

Kobayashi, Masaki; Mizumoto, Takashi; Duc, Trinh Quang; Takeda, Motohiro

2007-06-01

19

Ultrasound  

Cancer.gov

Ultrasound uses sound waves with frequencies above those humans can hear. A transducer sends sound waves traveling into the body which are reflected back from organs and tissues, allowing a picture to be made of the internal organs. Ultrasound can show

20

Therapeutic Ultrasound Enhancement of Drug Delivery to Soft Tissues  

NASA Astrophysics Data System (ADS)

Effects of exposure to 1.58 MHz focused ultrasound on transport of Evans Blue Dye (EBD) in soft tissues are investigated when an external pressure gradient is applied to induce convective flow through the tissue. The magnitude of the external pressure gradient is chosen to simulate conditions in brain parenchyma during convection-enhanced drug delivery (CED) to the brain. EBD uptake and transport are measured in equine brain, avian muscle and agarose brain-mimicking phantoms. Results show that ultrasound enhances EBD uptake and transport, and the greatest enhancement occurs when the external pressure gradient is applied. The results suggest that exposure of the brain parenchyma to ultrasound could enhance penetration of material infused into the brain during CED therapy.

Lewis, George; Olbricht, William

2009-04-01

21

Blood Flow Occlusion Via Ultrasound Image-Guided High-Intensity Focused Ultrasound and Its Effect on Tissue Perfusion  

Microsoft Academic Search

This study investigated the induction of tissue necrosis by arterial blood flow occlusion using ultrasound image-guided high-intensity focused ultrasound (HIFU). We constructed a prototype HIFU transducer in combination with an imaging probe that provided color Doppler imaging and ultrasound contrast imaging. The HIFU beam was aimed into a branch of the renal artery in vivo. The renal artery branches of

Mitsuyoshi Ichihara; Kazuaki Sasaki; Shin-Ichiro Umemura; Miki Kushima; Takashi Okai

2007-01-01

22

Ablation of tissue volumes using high intensity focused ultrasound  

Microsoft Academic Search

Successful application of high intensity focused ultrasound to cancer treatment requires complete ablation of tissue volumes. In order to destroy an entire tumour it is necessary to place a contiguous array of touching lesions throughout it. In a study of how best to achieve this, exposures were selected to give single lesions that were thermal in origin, while avoiding effects

A. L. Malcolm; G. R. ter Haar

1996-01-01

23

Transrectal ablation of prostate tissue using focused ultrasound  

Microsoft Academic Search

Canine and human prostates were treated with high intensity focused ultrasound (HIFU) using a transrectal probe. Near the beam focus, temperatures were shown to be greater than 60°C, while periprostatic tissue temperatures increased ⩽3°C; rectal wall temperatures did not rise more than 5°C over the baseline. In 15 patients with benign prostatic hyperplasia (BPH), no major complications resulted from HIFU

N. T. Sanghvi; R. S. Foster; R. Bihrle; F. J. Fry; M. Phillips; C. Hennige

1993-01-01

24

Changes in ultrasound properties of porcine kidney tissue during heating  

Microsoft Academic Search

Changes in the ultrasound (US) attenuation and backscatter of fresh pig kidney were measured as the tissue was heated. The objective was to use these changes to predict how an US image would change in real-time with a view to its use as a monitoring tool for minimally invasive thermal therapy (MITT). Separate samples of fresh pig kidney were heated

A. E Worthington; M. D Sherar

2001-01-01

25

Slow light for deep tissue imaging with ultrasound modulation  

PubMed Central

Slow light has been extensively studied for applications ranging from optical delay lines to single photon quantum storage. Here, we show that the time delay of slow-light significantly improves the performance of the narrowband spectral filters needed to optically detect ultrasound from deep inside highly scattering tissue. We demonstrate this capability with a 9?cm thick tissue phantom, having 10?cm?1 reduced scattering coefficient, and achieve an unprecedented background-free signal. Based on the data, we project real time imaging at video rates in even thicker phantoms and possibly deep enough into real tissue for clinical applications like early cancer detection.

Zhang, Huiliang; Sabooni, Mahmood; Rippe, Lars; Kim, Chulhong; Kroll, Stefan; Wang, Lihong V.; Hemmer, Philip R.

2012-01-01

26

Slow light for deep tissue imaging with ultrasound modulation  

NASA Astrophysics Data System (ADS)

Slow light has been extensively studied for applications ranging from optical delay lines to single photon quantum storage. Here, we show that the time delay of slow-light significantly improves the performance of the narrowband spectral filters needed to optically detect ultrasound from deep inside highly scattering tissue. We demonstrate this capability with a 9 cm thick tissue phantom, having 10 cm-1 reduced scattering coefficient, and achieve an unprecedented background-free signal. Based on the data, we project real time imaging at video rates in even thicker phantoms and possibly deep enough into real tissue for clinical applications like early cancer detection.

Zhang, Huiliang; Sabooni, Mahmood; Rippe, Lars; Kim, Chulhong; Kröll, Stefan; Wang, Lihong V.; Hemmer, Philip R.

2012-03-01

27

Use of stationary focused ultrasound fields for characterization of tissue and localized tissue ablation  

NASA Astrophysics Data System (ADS)

Ultrasound-induced blood stasis has been observed for more than 30 years. The physical understanding of the phenomenon has not been fully explored. Analytical descriptions of the acoustic interaction with spheres in suspension have been derived but the physical implications and limitations have not been demonstrated. The analytical expressions will be tested against physical observations using numerical simulations. The simulations will begin with stationary spheres and continue with the inclusion of moving spheres and a moving suspending fluid. To date, experimental observations of acoustically induced blood stasis have been either in vitro or invasive. We demonstrate ultrasound-induced blood stasis in murine normal leg muscle versus tumor-bearing legs, observed through noninvasive measurements of optical spectroscopy, and discuss possible diagnostic uses for this effect of ultrasound. We derive the optimal optical wavelengths for measuring the effects of the ultrasound at small source detector separations. Using optical oximetry performed at the optimal wavelengths, we demonstrate that effects of ultrasound can be used to differentiate tumor from normal leg muscle tissue in mice. To provide a statistical analysis of the experiments, we propose a novel diagnostic algorithm that quantitatively differentiates tumor from nontumor with maximum specificity 0.83, maximum sensitivity 0.79, and area under receiver-operating-characteristics curve 0.90. Ultrasound has long been known to cause tissue heating when applied in high intensities. More recently, interest has arisen in the area of High Intensity Focused Ultrasound (HIFU) for localized tissue heating effects, specifically thermal ablation. All present techniques employ focused traveling high intensity acoustic waves to create a region of elevated temperature. Such high intensity traveling waves can be damaging to normal tissue in the vicinity of the focal region, and have demonstrated surface burns and caused patient discomfort in certain clinical trials. Use of lower intensity ultrasound can minimize the side-effects presented by HIFU. We demonstrate the use of low intensity multiple beam ultrasound resulting in stationary acoustic fields which are capable of heating a very small and more precisely located region of tissue. We simulate the fields formed by traveling waves and stationary waves created by two opposing sources and two orthogonal sources. The simulations are compared to experimental results where the intensity of the individual ultrasound beams is within FDA diagnostic ultrasound limits (0.720 W/cm2). Temperature elevation that would cause cell death was achieved in tissue-mimicking phantoms after short exposures to the acoustic field in the region of beam overlap.

Winey, Brian Andrew

28

Incorporating tissue absorption and scattering in rapid ultrasound beam modeling  

NASA Astrophysics Data System (ADS)

We have developed a new approach for modeling the propagation of an ultrasound beam in inhomogeneous tissues such as encountered with high-intensity focused ultrasound (HIFU) for treatment of various diseases. This method, called the hybrid angular spectrum (HAS) approach, alternates propagation steps between the space and the spatial frequency domains throughout the inhomogeneous regions of the body; the use of spatial Fourier transforms makes this technique considerably faster than other modeling approaches (about 10 sec for a 141 x 141 x 121 model). In HIFU thermal treatments, the acoustic absorption property of the tissues is of prime importance since it leads to temperature rise and the achievement of desired thermal dose at the treatment site. We have recently added to the HAS method the capability of independently modeling tissue absorption and scattering, the two components of acoustic attenuation. These additions improve the predictive value of the beam modeling and more accurately describes the thermal conditions expected during a therapeutic ultrasound exposure. Two approaches to explicitly model scattering were developed: one for scattering sizes smaller than a voxel, and one when the scattering scale is several voxels wide. Some anatomically realistic examples that demonstrate the importance of independently modeling absorption and scattering are given, including propagation through the human skull for noninvasive brain therapy and in the human breast for treatment of breast lesions.

Christensen, Douglas; Almquist, Scott

2013-02-01

29

Ultrasound therapy applicators for controlled thermal modification of tissue  

NASA Astrophysics Data System (ADS)

Heat therapy has long been used for treatments in dermatology and sports medicine. The use of laser, RF, microwave, and more recently, ultrasound treatment, for psoriasis, collagen reformation, and skin tightening has gained considerable interest over the past several years. Numerous studies and commercial devices have demonstrated the efficacy of these methods for treatment of skin disorders. Despite these promising results, current systems remain highly dependent on operator skill, and cannot effectively treat effectively because there is little or no control of the size, shape, and depth of the target zone. These limitations make it extremely difficult to obtain consistent treatment results. The purpose of this study was to determine the feasibility for using acoustic energy for controlled dose delivery sufficient to produce collagen modification for the treatment of skin tissue in the dermal and sub-dermal layers. We designed and evaluated a curvilinear focused ultrasound device for treating skin disorders such as psoriasis, stimulation of wound healing, tightening of skin through shrinkage of existing collagen and stimulation of new collagen formation, and skin cancer. Design parameters were examined using acoustic pattern simulations and thermal modeling. Acute studies were performed in 201 freshly-excised samples of young porcine underbelly skin tissue and 56 in-vivo treatment areas in 60- 80 kg pigs. These were treated with ultrasound (9-11MHz) focused in the deep dermis. Dose distribution was analyzed and gross pathology assessed. Tissue shrinkage was measured based on fiducial markers and video image registration and analyzed using NIH Image-J software. Comparisons were made between RF and focused ultrasound for five energy ranges. In each experimental series, therapeutic dose levels (60degC) were attained at 2-5mm depth. Localized collagen changes ranged from 1-3% for RF versus 8-15% for focused ultrasound. Therapeutic ultrasound applied at high frequencies can achieve temperatures and dose distributions which concentrate in a depth profile that coincides with the location of maximum structural collagen content in skin tissues. Using an appropriate transducer configuration produces coverage of significant lateral area, thus making this a practical approach for treatment of skin disorders.

Burdette, E. Clif; Lichtenstiger, Carol; Rund, Laurie; Keralapura, Mallika; Gossett, Chad; Stahlhut, Randy; Neubauer, Paul; Komadina, Bruce; Williams, Emery; Alix, Chris; Jensen, Tor; Schook, Lawrence; Diederich, Chris J.

2011-02-01

30

Diffraction tomography applied to simulated ultrasound through breast tissue  

NASA Astrophysics Data System (ADS)

Diffraction tomography is used to obtain images of sound speed and attenuation of a slice of breast tissue obtained from the Visible Woman data set. Simulated ultrasound data was generated using an acoustic propagation code run on the ASCI Blue Pacific computer at Lawrence Livermore National Laboratory. Data was generated for a slice of healthy tissue, and a slice with simulated lesions to determine the ability of the imaging method to detect various abnormalities in the breast. In addition, the time reversal operator for the slice was constructed from the data and the eigenfunctions backpropagated into the slice as first suggested by Mast [Mast, Nachman, and Waag, J. Acoust. Soc. Am. 102(2)] to identify structures associated with each time reversal mode for both the healthy tissue and tissue with lesions.

Chambers, David H.

2002-11-01

31

Ultrasonic atomization of tissue and its role in tissue fractionation by high intensity focused ultrasound.  

PubMed

Atomization and fountain formation is a well-known phenomenon that occurs when a focused ultrasound wave in liquid encounters an air interface. High intensity focused ultrasound (HIFU) has been shown to fractionate a tissue into submicron-sized fragments in a process termed boiling histotripsy, wherein the focused ultrasound wave superheats the tissue at the focus, producing a millimetre-sized boiling or vapour bubble in several milliseconds. Yet the question of how this millimetre-sized boiling bubble creates submicron-sized tissue fragments remains. The hypothesis of this work is that the tissue can behave as a liquid such that it atomizes and forms a fountain within the vapour bubble produced in boiling histotripsy. We describe an experiment, in which a 2 MHz HIFU transducer (maximum in situ intensity of 24?000 W cm(-2)) was aligned with an air-tissue interface meant to simulate the boiling bubble. Atomization and fountain formation was observed with high-speed photography and resulted in tissue erosion. Histological examination of the atomized tissue showed whole and fragmented cells and nuclei. Air-liquid interfaces were also filmed. Our conclusion was that HIFU can fountain and atomize tissue. Although this process does not entirely mimic what was observed in liquids, it does explain many aspects of tissue fractionation in boiling histotripsy. PMID:23159812

Simon, Julianna C; Sapozhnikov, Oleg A; Khokhlova, Vera A; Wang, Yak-Nam; Crum, Lawrence A; Bailey, Michael R

2012-11-16

32

Quantitative ultrasound (QUS) assessment of tissue properties for Achilles tendons  

NASA Astrophysics Data System (ADS)

Quantitative ultrasound (QUS) techniques have recently been widely applied for the characterization of tissues. For example, they can be used for the quantification of Achilles tendon properties based on the broadband ultrasound attenuation (BUA) and the speed of sound (SOS) when the ultrasound wave passes through the tissues. This study is to develop an integrated system to investigate the properties of Achilles tendons using QUS images from UBIS 5000 (DMS, Montpellier, France) and B-mode ultrasound images from HDI 5000 (ATL, Ultramark, USA). Subjects including young (32 females and 17 males; mean age: 23.7 ± 2.0) and middle-aged groups (8 female and 8 males; mean age: 47.3 ± 8.5 s) were recruited and tested for this study. Only subjects who did not exercise regularly and had no record of tendon injury were studied. The results show that the BUA is significantly higher for the young group (45.2 ± 1.6 dB MHz-1) than the middle-age group (40.5 ± 1.9 dB MHz-1), while the SOS is significantly lower for the young (1601.9 ± 11.2 ms-1) compared to the middle-aged (1624.1 ± 8.7 m s-1). On the other hand, the thicknesses of Achilles tendons for both groups (young: 4.31 ± 0.23 mm; middle age: 4.24 ± 0.23 mm) are very similar. For one patient who had an Achilles tendon lengthening (ATL) surgery, the thickness of the Achilles tendon increased from 4 mm to 4.33 mm after the surgery. In addition, the BUA increased by about 7.2% while the SOS decreased by about 0.6%. In conclusion, noninvasive ultrasonic assessment of Achilles tendons is useful for assisting clinical diagnosis and for the evaluation of a therapeutic regimen.

Du, Yi-Chun; Chen, Yung-Fu; Chen, Pei-Jarn; Lin, Yu-Ching; Chen, Tainsong; Lin, Chii-Jeng

2007-09-01

33

Development of Ultrasound Transducer with Double-Peak-Type Frequency Characteristics for Harmonic Imaging and Subharmonic Imaging  

NASA Astrophysics Data System (ADS)

Development of ultrasound transducers with double-peak-type frequency characteristics for harmonic imaging and subharmonic imaging is reported in this paper. The peak on the low-frequency side in the frequency characteristics is used to transmit ultrasound into tissues or microbubble ultrasound contrast agents, and another peak on the high-frequency side is used to receive the second harmonic component in the ultrasound transducer with double-peak-type frequency characteristics for harmonic imaging. On the other hand, the peak on the high-frequency side in the frequency characteristics is used to transmit ultrasound and another peak on the low-frequency side is used to receive the 1/2 subharmonic component in the ultrasound transducer with double-peak-type frequency characteristics for subharmonic imaging. The results of the transducer design based on numerical calculation are reported in this paper.

Takeuchi, Shinichi; Zaabi, Mohamed Rashed Ali Al; Sato, Toshio; Kawashima, Norimichi

2002-05-01

34

Effect of osmosis and ultrasound on pineapple cell tissue structure during dehydration  

Microsoft Academic Search

The effect of ultrasound-assisted osmotic dehydration applied for different lengths of time on pineapple tissue structure was evaluated. Using distilled water as the liquid medium, ultrasound induced disruption of cells and formation of microscopic channels in the fruit structure but did not induce breakdown of the cells. Consequently, ultrasound application increased sugar loss and water diffusivity because of the formation

Fabiano A. N. Fernandes; Maria Izabel Gallão; Sueli Rodrigues

2009-01-01

35

Noninvasive surgery of prostate tissue by high-intensity focused ultrasound  

Microsoft Academic Search

Modern ultrasound transducer material and matching layer technology has permitted us to combine the ultrasound visualization capability with production of high-intensity focused ultrasound (HIFU) on the same ceramic crystal. This development has lead to the design of a transrectal probe for noninvasive surgery of prostate tissue by HIFU. The combined capability using the same ceramic crystal simplifies treatment planning, targeting,

Narendra T. Sanghvi; F. J. Fry; R. Bihrle; R. S. Foster; M. H. Phillips; J. Syrus; A. V. Zaitsev; C. W. Hennige

1996-01-01

36

Statistical Parameter Estimation in Ultrasound Backscattering from Tissue Mimicking Media.  

NASA Astrophysics Data System (ADS)

Several tissue characterization parameters, including the effective scatterer number density and the backscatter coefficient, were derived from the statistical properties of ultrasonic echo signals. The effective scatterer number density is the actual scatterer number density in a medium multiplied by a frequency-dependent factor that depends on the differential scattering cross-sections of all scatterers. The method described in this thesis for determining the scatterer number density explicitly retains both the temporal nature of the data acquisition and the properties of the ultrasound field in the data reduction. Moreover, it accounts for the possibility that different sets of scatterers may dominate the echo signal at different frequencies. The random processes involved in forming ultrasound echo signals from random media give rise to an uncertainty in the estimated effective scatterer number density. This uncertainty is evaluated using error propagation. The statistical uncertainty depends on the effective number of scatterers contributing to the segmented echo signal, increasing when the effective number of scatterers increases. Tests of the scatterer number density data reduction method and the statistical uncertainty estimator were done using phantoms with known ultrasound scattering properties. Good agreement was found between measured values and those calculated from first-principles. The properties of the non-Gaussian and non-Rayleigh parameters of ultrasound echo signals are also studied. Both parameters depend on the measurement system, including the transducer field and pulse frequency content, as well as on the medium's properties. The latter is expressed in terms of the scatterer number density and the second and fourth moments of the medium's scattering function. A simple relationship between the non-Gaussian and non-Rayleigh parameters is derived and verified experimentally. Finally, a reference phantom method is proposed for measuring the effective scatterer number density in vivo. Various groups are using the frequency dependent backscatter coefficient (or the spatial autocorrelation function) to characterize scatterer sizes in biological tissue. Generally, sparse scatterer concentrations are assumed in relating scattering parameters to this tissue property. For dense scattering media, we study whether the frequency dependent backscatter coefficient changes with the scatterer volume fraction. Two scattering models suggested by Debye and Yagi are reviewed. In these models, the spatial autocorrelation function describing mass density and compressibility fluctuations in the scattering medium has a characteristic length that depends on the scatterer volume fraction as well as the scatterer size. The models predict the frequency dependence of the backscatter coefficient will vary with the scatterer volume fraction. Qualitative agreement between the model predictions and experimental results are seen for sephadex-in-agar phantoms.

Chen, Jian-Feng

37

DUAL-FOCUS THERAPEUTIC ULTRASOUND TRANSDUCER FOR PRODUCTION OF BROAD TISSUE LESIONS  

PubMed Central

In noninvasive high-intensity focused ultrasound (HIFU) treatment, formation of a large tissue lesion per sonication is desirable for reducing the overall treatment time. The goal of this study is to show the feasibility of enlarging tissue lesion size with a dual-focus therapeutic ultrasound transducer (DFTUT) by increasing the depth-of-focus (DOF). The proposed transducer consists of a disc- and an annular-type element of different radii of curvatures to produce two focal zones. To increase focal depth and to maintain uniform beamwidth of the elongated DOF, each element transmits ultrasound of a different center frequency: the inner element at a higher frequency for near field focusing and the outer element at a lower frequency for far field focusing. By activating two elements at the same time with a single transmitter capable of generating a dual-frequency mixed signal, the overall DOF of the proposed transducer may be extended considerably. A prototype transducer composed of a 4.1 MHz inner element and a 2.7 MHz outer element was fabricated to obtain preliminary experimental results. The feasibility the proposed technique was demonstrated through sound field, temperature and thermal dose simulations. The performance of the prototype transducer was verified by hydrophone measurements and tissue ablation experiments on a beef liver specimen. When several factors affecting the length and the uniformity of elongated DOF of the DFTUT are optimized, the proposed therapeutic ultrasound transducer design may increase the size of ablated tissues in the axial direction and, thus, decreasing the treatment time for a large volume of malignant tissues especially deep-seated targets.

Jeong, Jong Seob; Cannata, Jonathan M.; Shung, K. Kirk

2011-01-01

38

Optimal conditions for tissue perforation using high intensity focused ultrasound  

NASA Astrophysics Data System (ADS)

To perforate tissue lying deep part in body, a large size transducer was assembled by combining four spherical-shaped transducers, and the optimal conditions for tissue perforation have studied using ventricle muscle of chicken as a target. The ex vivo experiments showed that ventricle muscle was successfully perforated both when it was exposed to High Intensity Focused Ultrasound (HIFU) directly and when it was exposed to HIFU through atrial muscle layer. Moreover, it was shown that calculated acoustic power distributions are well similar to the perforation patterns, and that the acoustic energy distributes very complexly near the focus. Lastly, perforation on the living rabbit bladder wall was demonstrated as a preliminary in vivo experiment.

Mochizuki, Takashi; Kihara, Taizo; Ogawa, Kouji; Tanabe, Ryoko; Yosizawa, Shin; Umemura, Shin-ichiro; Kakimoto, Takashi; Yamashita, Hiromasa; Chiba, Toshio

2012-10-01

39

Characterization of tissue scaffolds using optics and ultrasound  

NASA Astrophysics Data System (ADS)

Tissue scaffolds are an integral part of the tissue engineering process, assisting in the culturing of cells in three dimensions. It is important to understand both the properties of the scaffold and the growth of cells within the scaffold. This paper describes a system to characterise scaffolds using acoustic techniques alone and the development of an ultrasound modulated optical tomography system to study the growth of cells within the scaffolds. Our interest is in characterising the properties of gel-based and polymer foam-based scaffolds. Results from a purely acoustic system have been used to investigate the properties of foam scaffolds manufactured from synthetic polyesters poly(lactic acid) (PLA) and poly(lactic-co-glycolic acid) (PLGA) via a supercritical fluid process. As these are porous materials, they are particularly challenging acoustically as the pores scatter sound significantly. However, it is demonstrated that acoustic signals are detectable through a 6mm thick scaffold. Although acoustics alone can be used to characterize many properties of the scaffolds, useful information can also be obtained from optical techniques e.g. monitoring the growth of cells within the scaffold via optical absorption or fluorescence techniques. Light scattering is of course a significant problem for relatively thick engineered tissue (~5mm). The acoustic approach has been extended to include laser illumination and detection of the ultrasound modulated optical pulse. Images of optically-absorbing materials embedded in gel-based tissue phantoms will be presented demonstrating that a lateral resolution of 250?m and an axial resolution of ~90?m can be achieved in scattering samples.

Huynh, N. T.; Parker, N. G.; He, D.; Ruan, H.; Hayes-Gill, B. R.; Mather, M. L.; Crowe, J. A.; Rose, F. R. A. J.; Povey, M. J. W.; Morgan, S. P.

2011-02-01

40

Medical ultrasound: imaging of soft tissue strain and elasticity  

PubMed Central

After X-radiography, ultrasound is now the most common of all the medical imaging technologies. For millennia, manual palpation has been used to assist in diagnosis, but it is subjective and restricted to larger and more superficial structures. Following an introduction to the subject of elasticity, the elasticity of biological soft tissues is discussed and published data are presented. The basic physical principles of pulse-echo and Doppler ultrasonic techniques are explained. The history of ultrasonic imaging of soft tissue strain and elasticity is summarized, together with a brief critique of previously published reviews. The relevant techniques—low-frequency vibration, step, freehand and physiological displacement, and radiation force (displacement, impulse, shear wave and acoustic emission)—are described. Tissue-mimicking materials are indispensible for the assessment of these techniques and their characteristics are reported. Emerging clinical applications in breast disease, cardiology, dermatology, gastroenterology, gynaecology, minimally invasive surgery, musculoskeletal studies, radiotherapy, tissue engineering, urology and vascular disease are critically discussed. It is concluded that ultrasonic imaging of soft tissue strain and elasticity is now sufficiently well developed to have clinical utility. The potential for further research is examined and it is anticipated that the technology will become a powerful mainstream investigative tool.

Wells, Peter N. T.; Liang, Hai-Dong

2011-01-01

41

Ultrasound properties of human prostate tissue during heating.  

PubMed

Changes in the ultrasound (US) properties of tissue during heating affect the delivery of US thermal therapy and may provide a basis for US image monitoring of thermal therapy. The US attenuation coefficient and backscatter power of fresh human prostate tissue were measured as the tissue was heated. Samples of human prostate were obtained directly from autopsies and heated rapidly to final temperatures of 45 degrees C, 50 degrees C, 55 degrees C, 60 degrees C and 65 degrees C. A 5.0-MHz transducer was scanned in a raster pattern over the tissue and radiofrequency (RF) data were collected at 36 uncorrelated positions. Both attenuation and backscatter were measured over the frequency range 3.5 to 7.0 MHz at each min of a 30-min heating. Little change was observed in attenuation or backscatter at 55 degrees C or less. The attenuation coefficient and backscatter power increased by factors of 1.25 and 5, respectively, during the 60 degrees C heating. During the 65 degrees C heating, the same properties showed increases by factors of 2.7 and 9. PMID:12467858

Worthington, A E; Trachtenberg, J; Sherar, M D

2002-10-01

42

Correction for soft tissue in cortical bone assessment by ultrasound  

NASA Astrophysics Data System (ADS)

One of the key points in ultrasound measurements on cortical bone is the correction for soft tissue. We designed a new probe based on bi-directional axial transmission which automatically compensates velocity measurements for the soft tissue effect without preliminary evaluation of soft tissue properties. The probe consists in a linear arrangement of transducers with two sources placed on both sides of a unique group of receivers. The velocity of waves propagating parallel to the bone axis is deduced from a combination of the time delays derived from waves propagating in opposite directions at successive receivers separated by a known distance. This technique efficiently corrects for the major source of error on velocity encountered in clinical measurements which is caused by the variation of soft tissue thickness along the probe. The bi-directional technique was validated on test samples for which the residual precision error on velocity measurements was reduced to 0.2%. In vivo measurements yielded a value of 0.5% for the interoperator reproducibility. The clinical range of variation of the velocity measured by bi-directional technique is evaluated using clinical measurements on more than 200 subjects. Bi-directional transmission is a promising technique to minimize the variability of in vivo velocity measurements.

Bossy, E.; Talmant, M.; Laugier, P.; Roux, C.; Kolta, S.; Haguenauer, D.

2004-10-01

43

A Novel Method to Obtain Modulus Image of Soft Tissues Using Ultrasound Water Jet Indentation: A Phantom Study  

Microsoft Academic Search

The alteration of tissue stiffness is generally known to be associated with pathological changes. Ultrasound indentation is one of the methods that can be used to assess the mechanical properties of the soft tissues. It uses a flat-ended ultrasound transducer to directly contact the tissue to sense tissue deformation under an applied load. This paper introduced a novel noncontact ultrasound

Min-Hua Lu; Yong-Ping Zheng; Qing-Hua Huang

2007-01-01

44

Gene delivery system involving Bubble liposomes and ultrasound for the efficient in vivo delivery of genes into mouse tongue tissue.  

PubMed

Oral squamous cell carcinoma is the most common type of head and neck cancer. Recently, efficient, easy, and minimally invasive gene delivery methods are expected to be developed as cancer gene therapies. However, the optimal method for delivering therapeutic genes into oral tissue for cancer treatment has not been elucidated. Therefore, we hypothesized that the tongue is a good target tissue for gene delivery with Bubble liposomes and ultrasound. To assess this, we attempted to deliver a mixture of plasmid DNA encoding a luciferase or enhanced green fluorescent protein, and Bubble liposomes into murine tongue with or without ultrasound exposure. The ultrasound conditions were 1 MHz, 2 W/cm(2), 60s, and duty cycle: 50%. The time-course of gene expression in the tongue was investigated with a luciferase assay and fluorescent microscopy. Luciferase expression was significantly increased in tongue transfected using Bubble liposomes and ultrasound compared with that of the tongue untreated with ultrasound, and this high level of luciferase activity was maintained for 2 weeks. From these results, Bubble liposomes can be used in combination with ultrasound to efficiently deliver plasmid DNA into the tongue in vivo. This technique is a highly promising approach for gene delivery into oral tissue. PMID:22100513

Sugano, Marika; Negishi, Yoichi; Endo-Takahashi, Yoko; Suzuki, Ryo; Maruyama, Kazuo; Yamamoto, Matsuo; Aramaki, Yukihiko

2011-11-11

45

Tissue Motion and Strain in the Human Brain Assessed by Intraoperative Ultrasound in Glioma Patients  

Microsoft Academic Search

The objective of the study was to investigate tissue motion and strain imposed by cardiovascular pulsation in pathologic and normal brain parenchyma, as quantified from in vivo ultrasound data. Ultrasound acquired during surgery of 16 patients with glial tumors was retrospectively processed and analyzed. The tissue velocity was quantified at depths of 1cm, 2cm and 3cm from brain cortex to

Tormod Selbekk; Reidar Brekken; Ole Solheim; Stian Lydersen; Toril A. N. Hernes; Geirmund Unsgaard

2010-01-01

46

Ultrasound phase-contrast transmission imaging of localized thermal variation in a breast tissue model  

Microsoft Academic Search

The present numeric study examines an ultrasound phase contrast method for imaging localized temperature rises in tissue, such as heating experienced in thermal ablation treatments. We tested the method's ability to produce thermal images by simulating the signal from a planar ultrasound source directed through tissue containing skin, fat, and muscle layers. Phase-contrast imaging only requires phase shifts a fraction

Greg Clement; Kullervo Hynynen

2003-01-01

47

Interactive development of a CT-based tissue model for ultrasound simulation.  

PubMed

The objective of this study was to make an interactive method for development of a tissue model, based on anatomical information in computed tomography (CT) images, for use in an ultrasound simulator for training or surgical pre-planning. The method consisted of (1) comparison of true ultrasound B-mode images with corresponding ultrasound-like images, and (2) modification of tissue properties to decrease the difference between these images. Ultrasound-like images that reproduced many, but not all the properties of corresponding true ultrasound images were generated. The tissue model could be used for real-time simulation of ultrasound-like B-mode images on a moderately priced computer. PMID:22424668

Gjerald, Sjur Urdson; Brekken, Reidar; Bø, Lars Eirik; Hergum, Torbjørn; Nagelhus Hernes, Toril A

2012-03-17

48

Effects of ultrasound contrast agents on Doppler tissue velocity estimation.  

PubMed

The combination of Doppler tissue imaging and myocardial contrast echocardiography has the potential to provide information about motion and perfusion of the myocardium in a single examination. The purpose of this study was to establish how the presence of ultrasound contrast agent (UCA) affects measurements of Doppler tissue velocities in vivo and in vitro. We performed echocardiography in 12 patients with ischemic heart disease before and immediately after a slow intravenous infusion of the UCA Optison, using color Doppler tissue imaging to examine the effect of contrast agents in vivo. The myocardial peak systolic velocities and their integrals were analyzed in digitally stored cineloops before and after contrast administration. To distinguish between methodologic and physiologic factors affecting the measurement of tissue velocity in vitro, experiments with a rotating disk and a flow cone phantom were also carried out for the 3 contrast agents: Optison, Sonovue, and Sonazoid. In vivo results show that the values for peak systolic velocity increased by about 10% during contrast infusion, from mean 5.2 +/- 1.8 to 5.7 +/- 2.3 cm/s (P = .02, 95% confidence interval 2%-16%). The increase in myocardial peak systolic velocities was verified in experimental models in which the UCA increased the estimated mean velocity in the order of 5% to 20% for the motion interval of 5 to 7 cm/s, corresponding to the myocardial velocities studied in vivo. The response was similar for all 3 contrast agents and was not affected by moderate variations in concentration of the agent. We have shown that the presence UCA will affect Doppler tissue measurements in vivo and in vitro. The observed bias is presumed to be an effect of harmonic signal contribution from rupturing contrast agent microbubbles and does not indicate biologic or physiologic effects. PMID:16455419

Ressner, Marcus; Brodin, Lars-Ake; Jansson, Tomas; Hoff, Lars; Ask, Per; Janerot-Sjoberg, Birgitta

2006-02-01

49

Spectral tissue strain: a new technique for imaging tissue strain using intravascular ultrasound.  

PubMed

Spectral tissue strain (STS) is a new technique for measuring and imaging tissue strain from a set of images using intravascular ultrasound. The technique is based on the Fourier scaling property and uses the chirp z-transform (CZT) to estimate strain within the vessel walls. Some preliminary results, both in vitro and in vivo, are described. A novel display technique has also been developed for encoding radial strain and displaying the resulting colour map as an overlay on the original image. PMID:7863565

Talhami, H E; Wilson, L S; Neale, M L

1994-01-01

50

Ultrasound accelerates transport of recombinant tissue plasminogen activator into clots  

Microsoft Academic Search

Fibrinolysis is accelerated in vitro in an ultrasound field, and externally applied high frequency ultrasound also accelerates thrombolysis in animal models. Although the mechanism of this effect is not known, ultrasound does not cause mechanical disruption of clots but rather accelerates enzymatic fibrinolysis. To determine if accelerated fibrinolysis could be related to increased transport of enzyme into clot, we have

Charles W. Francis; Ales Blinc; Simone Lee; Christopher Cox

1995-01-01

51

Viscoelastic Property Measurement in Thin Tissue Constructs Using Ultrasound  

PubMed Central

We present a dual-element concave ultrasound transducer system for generating and tracking of localized tissue displacements in thin tissue constructs on rigid substrates. The system is comprised of a highly focused PZT-4 5-MHz acoustic radiation force (ARF) transducer and a confocal 25-MHz polyvinylidene fluoride imaging transducer. This allows for the generation of measurable displacements in tissue samples on rigid substrates with thickness values down to 500 µm. Impulse-like and longer duration sine-modulated ARF pulses are possible with intermittent M-mode data acquisition for displacement tracking. The operations of the ARF and imaging transducers are strictly synchronized using an integrated system for arbitrary waveform generation and data capture with a shared timebase. This allows for virtually jitter-free pulse-echo data well suited for correlation-based speckle tracking. With this technique we could faithfully capture the entire dynamics of the tissue axial deformation at pulse-repetition frequency values up to 10 kHz. Spatio-temporal maps of tissue displacements in response to a variety of modulated ARF beams were produced in tissue-mimicking elastography phantoms on rigid substrates. The frequency response was measured for phantoms with different modulus and thickness values. The frequency response exhibited resonant behavior with the resonance frequency being inversely proportional to the sample thickness. This resonant behavior can be used in obtaining high-contrast imaging using magnitude and phase response to sinusoidally modulated ARF beams. Furthermore, a second order forced harmonic oscillator (FHO) model was shown to capture this resonant behavior. Based on the FHO model, we used the extended Kalman filter (EKF) for tracking the apparent modulus and viscosity of samples subjected to dc and sinusoidally modulated ARF. The results show that the stiffness (apparent modulus) term in the FHO is largely time-invariant and can be estimated robustly using the EKF. On the other hand, the damping (apparent viscosity) is time varying. These findings were confirmed by comparing the magnitude response of the FHO (with parameters obtained using the EKF) with the measured ones for different thin tissue constructs.

Liu, Dalong; Ebbini, Emad S.

2010-01-01

52

Ultrasound Stimulation of Type I Collagen and Type III Collagen Expression of Tendon Cells  

NASA Astrophysics Data System (ADS)

This study was designed to determine the effect of ultrasound on tendon cells intrinsic to rat Achilles tendon plated on collagen-coated dishes. Furthermore, the in vitro effect of ultrasound on type I collagen and type III collage expression of tendon cells was investigated. Cultured tendon cells were treated with ultrasound at a frequency of 1.0 MHz, either pulsed (duty factor: 20%) or continuous mode with the intensity of 1.0 W/cm2 for 5 minutes. The expression of type I collagen and type III collagen of tendon cells was evaluated by immunocytochemistry 24 hours after ultrasound treatment. The results revealed that tendon cells cultured on dishes without collagen coating would lyse and detach from the dish after ultrasound exposure. However, cells cultured on collagen-coated dishes proliferate actively. Immunocytochemical staining revealed that ultrasound treated tendon cells stained more strongly for type I collagen and type III collagen than control cells. In conclusion, a collagen-coated dish is essential to prevent cell lysis and detachment from the dish after ultrasound exposure. Furthermore, either continuous or pulsed ultrasound could stimulate the expression of type I collagen and type III collagen by tendon cells.

Chen, Huang-Chung; Tsai, Wen-Chung; Tang, Chu-Wen; Pang, Jong-Hwei S.

2005-03-01

53

Semi-automated Ultrasound Facial Soft Tissue Depth Registration: Method and Validation  

Microsoft Academic Search

ABSTRACT: A mobile and fast, semi-automatic ultrasound (US) system was developed for facial soft tissue depth registration. The system consists of an A-Scan ultrasound device connected to a portable PC with interfacing and controlling software. For 52 cephalometric landmarks, the system was tested for repeatability and accuracy,by evaluating intra-observer agreement,and comparing,ultrasound and CT-scan results on 12 subjects planned for craniofacial

Sven De Greef; Peter Claes; Wouter Mollemans; Miet Loubele; Dirk Vandermeulen; Paul Suetens; Guy Willems

2005-01-01

54

Targeted damage effects of high intensity focused ultrasound (HIFU) on liver tissues of Guizhou province miniswine  

Microsoft Academic Search

HIFU can pass through tissues and accurately damage target tissues inside organisms. This article reports on the oriented damage effects of HIFU upon miniswine internal and external liver tissues, and suggests a new conception of the ‘biological focal field’. The results revealed that: (1) HIFU can be used to damage accurately liver tissues under the guide of a B-modal ultrasound

Zhi B. Wang; Feng Wu; Zhi L. Wang; Zhe Zhang; Jian Z. Zou; Chuan Liu; Yu G. Liu; Xun Cheng; Yong H. Du; Zheng C. He; Mei L. Gu; Zhi G. Wang; Ruo Feng

1997-01-01

55

Heating in vascular tissue and flow-through tissue phantoms induced by focused ultrasound  

NASA Astrophysics Data System (ADS)

High intensity focused ultrasound (HIFU) can be used to control bleeding, both from individual blood vessels as well as from gross damage to the capillary bed. This process, called acoustic hemostasis, is being studied in the hope that such a method would ultimately provide a lifesaving treatment during the so-called "golden hour", a brief grace period after a severe trauma in which prompt therapy can save the life of an injured person. Thermal effects play a major role in occlusion of small vessels and also appear to contribute to the sealing of punctures in major blood vessels. However, aggressive ultrasound-induced tissue heating can also impact healthy tissue and can lead to deleterious mechanical bioeffects. Moreover, the presence of vascularity can limit one's ability to elevate the temperature of blood vessel walls owing to convective heat transport. In an effort to better understand the heating process in tissues with vascular structure we have developed a numerical simulation that couples models for ultrasound propagation, acoustic streaming, ultrasound heating and blood cooling in Newtonian viscous media. The 3-D simulation allows for the study of complicated biological structures and insonation geometries. We have also undertaken a series of in vitro experiments, in non-uniform flow-through tissue phantoms, designed to provide a ground truth verification of the model predictions. The calculated and measured results were compared over a range of values for insonation pressure, insonation time, and flow rate; we show good agreement between predictions and measurements. We then conducted a series of simulations that address two limiting problems of interest: hemostasis in small and large vessels. We employed realistic human tissue properties and considered more complex geometries. Results show that the heating pattern in and around a blood vessel is different for different vessel sizes, flow rates and for varying beam orientations relative to the flow axis. Complete occlusion and wall-puncture sealing are both possible depending on the exposure conditions. These results concur with prior clinical observations and may prove useful for planning of a more effective procedure in HIFU treatments.

Huang, Jinlan

56

Bedside Ultrasound for the Detection of Soft Tissue Foreign Bodies: A Cadaveric Study  

Microsoft Academic Search

The objective of this study was to evaluate the sensitivity and specificity of bedside ultrasound, as performed by emergency physicians with typical equipment, in detecting small, soft tissue foreign bodies, using a cadaveric model. This was a prospective study, using 6 unembalmed human cadavers and 6 ultrasound-credentialed, emergency medicine residency-trained physicians as sonographers. Incisions were made in 150 total sites

Chad S. Crystal; David A. Masneri; John S. Hellums; David W. Kaylor; Scott E. Young; Michael A. Miller; Marc E. Levsky

2009-01-01

57

Numerical simulation of ultrasound-thermotherapy combining nonlinear wave propagation with broadband soft-tissue absorption  

Microsoft Academic Search

Ultrasound (US) thermotherapy is used to treat tumours, located deep in human tissue, by heat. It features by the application of high intensity focused ultrasound (HIFU), high local temperatures of about 90?C and short treating time of a few seconds. Dosage of the therapy remains a problem. To get it under control, one has to know the heat source, i.e.

S Ginter

2000-01-01

58

Ultrasound Doppler tissue image analysis based on neural network  

NASA Astrophysics Data System (ADS)

A new method for quantitative analysis of ultrasound Doppler tissue images (DTI) has been developed based on a neural network. The method aims to extract numerical data of velocity or acceleration from DTI images and analyze them quantitatively. A three-layered back propagation (BP) neural network is used to accomplish this task. The input of the network is the differences between the red, green and blue components of pixels and the output is the acceleration or velocity values. The network is trained with the color bars in the DTI images. The result of analyzing the movement of the left ventricle anterior free wall (LVAW) from DTA (DTI acceleration mode) image sequences is presented. The result of time-acceleration curve is highly correlated with the electrocardiogram (ECG) curve and gives us a quantitative and graphic description of the ventricle movement in cardiac cycles. It shows the movement characteristics of the left ventricle in cardiac cycles and also shows the excitation differences among the three layers of the myocardium. It is demonstrated that the method has great potential to characterize myocardial movement, which may provide a new way to characterize cardiac activities.

Zhao, Shukui; Li, Deyu; Yin, Lixue; Wang, Tianfu; Zheng, Changqiong; Zheng, Yi

2001-09-01

59

Changes in ultrasound properties of porcine kidney tissue during heating.  

PubMed

Changes in the ultrasound (US) attenuation and backscatter of fresh pig kidney were measured as the tissue was heated. The objective was to use these changes to predict how an US image would change in real-time with a view to its use as a monitoring tool for minimally invasive thermal therapy (MITT). Separate samples of fresh pig kidney were heated from 37 degrees C to temperatures of 45 degrees, 50 degrees, 55 degrees, 60 degrees and 65 degrees with warm water. Measurements were made over the frequency range from 3.5 MHz to 7.0 MHz during 30-min heating experiments. A general increase in attenuation magnitude (dB/cm) and slope (dB/cm-MHz) was observed at temperatures of 55 degrees C or greater. Little change in backscatter power was observed during heating to 45 degrees C. At higher temperatures, the changes in backscatter showed a more complex pattern throughout the experiments, but still showed a trend of increase to a greater value at the end of heating than at the start. This backscatter increase was greater at higher temperatures. The net effect of the changes in US properties suggests that it may be possible to use diagnostic US to monitor, in real-time, MITT in kidney. PMID:11397532

Worthington, A E; Sherar, M D

2001-05-01

60

Blood flow occlusion via ultrasound image-guided high-intensity focused ultrasound and its effect on tissue perfusion.  

PubMed

This study investigated the induction of tissue necrosis by arterial blood flow occlusion using ultrasound image-guided high-intensity focused ultrasound (HIFU). We constructed a prototype HIFU transducer in combination with an imaging probe that provided color Doppler imaging and ultrasound contrast imaging. The HIFU beam was aimed into a branch of the renal artery in vivo. The renal artery branches of eight rabbits were occluded by HIFU at an intensity of 4 kW/cm(2) (from 2 to 10 times of each sonication for 5 s). When the HIFU exposure was successful, complete cessation of blood flow was observed by color Doppler imaging with success rate of 100% (8/8). Furthermore, lack of perfusion was observed in the renal cortex with a contrast-enhanced image. Postmortem histologic evaluation showed a wedge-shaped area of infarction in six of seven cases, corresponding to the lack of the contrast medium in the ultrasound image. These results demonstrated that ultrasound image-guided HIFU can be used to induce arterial occlusion, thus producing infarction and necrosis of the perfused tissue. PMID:17208351

Ichihara, Mitsuyoshi; Sasaki, Kazuaki; Umemura, Shin-ichiro; Kushima, Miki; Okai, Takashi

2007-03-01

61

Is therapeutic ultrasound effective in treating soft tissue lesions?  

Microsoft Academic Search

Of 76 patients with lateral epicondylitis, 38 were randomly allocated to receive ultrasound treatment and 38 placebo. All 76 were given 12 treatments each over four to six weeks. The conditions of 24 patients (63%) treated with ultrasound and 11 (29%) given placebo improved, the difference being significant at the 1% level. Improvement in particular clinical variables (pain score, weight

A Binder; G Hodge; A M Greenwood; B L Hazleman; D P Page Thomas

1985-01-01

62

Multispectral photoacoustic imaging of tissue denaturation induced by high-intensity focused ultrasound treatment  

NASA Astrophysics Data System (ADS)

This paper presents an ex vivo study in imaging high-intensity focused ultrasound induced tissue denaturation with multispectral photoacoustic approach. Beef tissues treated by both water bath and high-intensity focused ultrasound were imaged and evaluated by photoacoustic imaging method, where light in multiple optical wavelengths between 700nm and 900nm is applied. Tissue denaturation after being treated by water bath and high-intensity focused ultrasound has been observed in multispectral photoacoustic images. The denaturation is more striking in relatively shorter optical wavelength photoacoustic images than in relatively longer optical wavelength photoacoustic images. This study suggests that multispectral photoacoustic imaging method is promising in the evaluation of tissue denaturation induced by high- intensity focused ultrasound treatment.

Sun, Yao; Li, King C. P.; O'Neill, Brian

2013-03-01

63

High frequency ultrasound signal statistics from mouse mammary tissue during involution  

Microsoft Academic Search

We investigate the use of signal envelope statistics to monitor the tissue restructuring process during mouse mammary tissue involution. Using an f\\/3 transducer operating at a centre frequency of 20 MHz, ultrasound backscatter data were collected from mouse mammary tissue following removal of the litter. The signal envelope statistics were examined by fitting the Rayleigh and generalized gamma distributions. The

A. S. Tunis; D. Spurrell; D. McAlduff; A. Giles; M. Hariri; R. Khokha; M. D. Sherar; G. J. Czarnota; Michael Kolios

2004-01-01

64

A new approach to analysis of RF ultrasound echo signals for tissue characterization: animal studies  

Microsoft Academic Search

We present the results of an animal tissue characterization study to demonstrate the effectiveness of a novel approach in collecting and analyzing ultrasound echo signals. In this approach, we continuously record RF echo signals backscattered from a tissue sample, while the imaging probe and the tissue are fixed in position. The continuously recorded RF data generates a time series of

Mehdi Moradi; Parvin Mousavi; Philip A. Isotalo; David R. Siemens; Eric E. Sauerbrei; Purang Abolmaesumi

2007-01-01

65

Temperature elevation of biological tissue model exposed by focused ultrasound with acoustic radiation force  

NASA Astrophysics Data System (ADS)

Focused ultrasound with acoustic radiation force (ARF) is beginning to be used for imaging and measuring tissue elasticity. On the other hand, it was suggested that the temperature elevation near bone at focus may be significant within the limits of acoustic output regulation in diagnostic ultrasound devices (Herman; 2002). In this study, with the aim of obtaining the relationships between temperature elevations and parameters of ultrasound exposure with ARF, temperature elevations in two kinds of tissue models with or without bone were numerically evaluated. The results showed that the temperature elevation at focus on the surface of bone may exceed an allowable temperature elevation which WFUMB guideline recommends, even though the acoustic intensity is within the limits of acoustic output regulation in diagnostic ultrasound devices.

Nitta, Naotaka; Kudo, Nobuki; Akiyama, Iwaki

2012-09-01

66

Selective transcutaneous delivery of energy to porcine soft tissues using intense ultrasound (IUS)  

Microsoft Academic Search

Objective: Various energy delivery systems have been utilized to treat superficial rhytids in the aging face. The Intense Ultrasound System (IUS) is a novel modality capable of transcutaneously delivering controlled thermal energy at various depths while sparing the overlying tissues. The purpose of this feasibility study was to evaluate the response of porcine tissues to various IUS energy source conditions.

W. Matthew White; Inder Raj S. Makin; Michael H. Slayton; Peter G. Barthe; Richard Gliklich

2008-01-01

67

The Effect of Soft-tissue Ultrasound on the Management of Cellulitis in the Emergency Department  

Microsoft Academic Search

Objectives: To evaluate the effect of diagnostic soft-tissue ultrasound (US) on management of emergency department (ED) patients with clinical cellulitis. Methods: This was a prospective observational study in an urban ED of adult patients with clinical soft- tissue infection without obvious abscess. The treating physician's pretest opinions regarding the need for further drainage procedures and the probability of subcutaneous fluid

Vivek S. Tayal; Nael Hasan; H. James Norton; Christian A. Tomaszewski

2006-01-01

68

Development and characterization of an innovative synthetic tissue-mimicking material for high intensity focused ultrasound (HIFU) exposures  

Microsoft Academic Search

While many tissue-mimicking phantoms have been developed for ultrasound imaging applications, none is suitable for exploration of the high temperature and pressure regimes involved in High Intensity Focused Ultrasound (HIFU). HIFU dosimetry studies are usually performed on biological tissues, but this approach has two drawbacks: 1) tissues are opaque and development of coagulative lesions cannot be visually observed in real-time,

Cyril Lafon; Peter J. Kaczkowski; Shahram Vaezy; Misty Noble; Oleg A. Sapozhnikov

2001-01-01

69

Ultrasound therapy applicators for controlled thermal modification of tissue  

Microsoft Academic Search

Heat therapy has long been used for treatments in dermatology and sports medicine. The use of laser, RF, microwave, and more recently, ultrasound treatment, for psoriasis, collagen reformation, and skin tightening has gained considerable interest over the past several years. Numerous studies and commercial devices have demonstrated the efficacy of these methods for treatment of skin disorders. Despite these promising

E. Clif Burdette; Carol Lichtenstiger; Laurie Rund; Mallika Keralapura; Chad Gossett; Randy Stahlhut; Paul Neubauer; Bruce Komadina; Emery Williams; Chris Alix; Tor Jensen; Lawrence Schook; Chris J. Diederich

2011-01-01

70

Contrast-enhanced ultrasound assessment of tissue response to high-intensity focused ultrasound  

Microsoft Academic Search

We report the use of contrast-enhanced ultrasonography as an immediate means of assessing the clinical response to high-intensity focused ultrasound (US) or HIFU treatment of liver tumours. HIFU is a noninvasive transcutaneous technique for the ablation of tumours that has been shown to destroy tumour vasculature, as well as to cause coagulative necrosis of tumour cells. As a dynamic indicator

James E Kennedy; Gail R ter Haar; Feng Wu; Fergus V Gleeson; Ian S. D Roberts; Mark R Middleton; David Cranston

2004-01-01

71

Non-invasive estimation of thermal tissue properties by high-intensity focused ultrasound  

NASA Astrophysics Data System (ADS)

Magnetic Resonance guided High-intensity Focused Ultrasound (MR-HIFU) can be used to locally heat tissue while non-invasively monitoring tissue temperature via MR-based thermometry. The goal of this study was to investigate the use of a computational technique based on inverse heat-transfer modeling for the non-invasive measurement of thermal tissue properties from data collected using an MR-HIFU system.

Appanaboyina, Sunil; Partanen, Ari; Haemmerich, Dieter

2013-02-01

72

Effect of Pulsed Low-Power Ultrasound on Growing Tissues  

Microsoft Academic Search

Pulsed ultrasound at 2.25 MHz was delivered by a transducer having an average power output of 1.5 mW to developing rat embryos in utero for 5 min and to larval and pupal stages of Drosophila melanogaster for 2.5 min. These exposures in some instances were lethal, in others growth inhibiting, and in still others, produced no detectable effect. Effects were

Donald J. Pizzarello; Alfred Vivino; Barbara Madden; Alexander Wolsky; Albert F. Keegan; Melvin Becker

1978-01-01

73

A tissue phantom for visualization and measurement of ultrasound-induced cavitation damage  

PubMed Central

Many ultrasound studies involve the use of tissue-mimicking materials to research phenomena in-vitro and predict in-vivo bioeffects. We have developed a tissue phantom to study cavitation-induced damage to tissue. The phantom consists of red blood cells suspended in an agarose hydrogel. The acoustic and mechanical properties of the gel phantom were found to be similar to soft tissue properties. The phantom’s response to cavitation was evaluated using histotripsy. Histotripsy causes breakdown of tissue structures by generation of controlled cavitation using short, focused, high-intensity ultrasound pulses. Histotripsy lesions were generated in the phantom and kidney tissue using a spherically focused 1-MHz transducer generating 15 cycle pulses at a pulse repetition frequency of 100 Hz with a peak negative pressure of 14 MPa. Damage appeared clearly as increased optical transparency of the phantom due to rupture of individual red blood cells. The morphology of lesions generated in the phantom was very similar to that generated in kidney tissue, at both macroscopic and cellular levels. Additionally, lesions in the phantom could be visualized as hypoechoic regions on a B-Mode ultrasound image, similar to histotripsy lesions in tissue. High speed imaging of the optically-transparent phantom was used to show that damage coincides with the presence of cavitation. These results indicate that the phantom can accurately mimic the response of soft tissue to cavitation and provide a useful tool for studying damage induced by acoustic cavitation.

Maxwell, Adam D.; Wang, Tzu-Yin; Yuan, Lingqian; Duryea, Alexander P.; Xu, Zhen; Cain, Charles A.

2010-01-01

74

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

PubMed

In this paper, we introduce a C-scan ultrasound prototype and three imaging modalities for the detection of foreign objects inserted in porcine soft tissue. The object materials include bamboo, plastics, glass and aluminum alloys. The images of foreign objects were acquired using the C-scan ultrasound, a portable B-scan ultrasound, film-based radiography, and computerized radiography. The C-scan ultrasound consists of a plane wave transducer, a compound acoustic lens system, and a newly developed ultrasound sensor array based on the complementary metal-oxide semiconductor coated with piezoelectric material (PE-CMOS). The contrast-to-noise ratio (CNR) of the images were analyzed to quantitatively evaluate the detectability using different imaging modalities. The experimental results indicate that the C-scan prototype has better CNR values in 4 out of 7 objects than other modalities. Specifically, the C-scan prototype provides more detail information of the soft tissues without the speckle artifacts that are commonly seen with conventional B-scan ultrasound, and has the same orientation as the standard radiographs but without ionizing radiation. PMID:20036873

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

2010-01-01

75

Algorithms and Results of Eye Tissues Differentiation Based on RF Ultrasound  

PubMed Central

Algorithms and software were developed for analysis of B-scan ultrasonic signals acquired from commercial diagnostic ultrasound system. The algorithms process raw ultrasonic signals in backscattered spectrum domain, which is obtained using two time-frequency methods: short-time Fourier and Hilbert-Huang transformations. The signals from selected regions of eye tissues are characterized by parameters: B-scan envelope amplitude, approximated spectral slope, approximated spectral intercept, mean instantaneous frequency, mean instantaneous bandwidth, and parameters of Nakagami distribution characterizing Hilbert-Huang transformation output. The backscattered ultrasound signal parameters characterizing intraocular and orbit tissues were processed by decision tree data mining algorithm. The pilot trial proved that applied methods are able to correctly classify signals from corpus vitreum blood, extraocular muscle, and orbit tissues. In 26 cases of ocular tissues classification, one error occurred, when tissues were classified into classes of corpus vitreum blood, extraocular muscle, and orbit tissue. In this pilot classification parameters of spectral intercept and Nakagami parameter for instantaneous frequencies distribution of the 1st intrinsic mode function were found specific for corpus vitreum blood, orbit and extraocular muscle tissues. We conclude that ultrasound data should be further collected in clinical database to establish background for decision support system for ocular tissue noninvasive differentiation.

Jurkonis, R.; Janusauskas, A.; Marozas, V.; Jegelevicius, D.; Daukantas, S.; Patasius, M.; Paunksnis, A.; Lukosevicius, A.

2012-01-01

76

Basic Investigation of Three-Dimensional Ultrasound Tissue Viscoelasticity Microscope  

NASA Astrophysics Data System (ADS)

The mechanical properties, or elasticity and viscosity, of tissues reflect the pathological change of tissues caused by lifestyle-related diseases such as cancer and cardiac disease. Therefore, tissue elasticity imaging has been investigated for several years and a practical system applicable to clinical diagnosis has recently been developed. To diagnose the stage of disease progression and differentiate malignant from benign tumors precisely using parameters that represent tissue elasticity and viscosity, it is required to elucidate the quantitative relationship between these parameters and disease. However, no database for such a relationship has been yet established. With the aim of constructing such a database, we undertook to develop a three-dimensional (3D) tissue viscoelasticity microscope, with which we can quantitatively measure the 3D distribution of parameters of tissue elasticity and viscosity. Results of experiments using a phantom model made of konnyaku and acrylamide confirmed that the system could reveal differences in the elasticity and viscosity of tissues.

Shiina, Tsuyoshi; Yoshida, Masashi; Yamakawa, Makoto; Nitta, Naotaka

2007-07-01

77

Combined chirp coded tissue harmonic and fundamental ultrasound imaging for intravascular ultrasound: 20-60 MHz phantom and ex vivo results.  

PubMed

The application of chirp coded excitation to pulse inversion tissue harmonic imaging can increase signal to noise ratio. On the other hand, the elevation of range side lobe level, caused by leakages of the fundamental signal, has been problematic in mechanical scanners which are still the most prevalent in high frequency intravascular ultrasound imaging. Fundamental chirp coded excitation imaging can achieve range side lobe levels lower than -60dB with Hanning window, but it yields higher side lobes level than pulse inversion chirp coded tissue harmonic imaging (PI-CTHI). Therefore, in this paper a combined pulse inversion chirp coded tissue harmonic and fundamental imaging mode (CPI-CTHI) is proposed to retain the advantages of both chirp coded harmonic and fundamental imaging modes by demonstrating 20-60MHz phantom and ex vivo results. A simulation study shows that the range side lobe level of CPI-CTHI is 16dB lower than PI-CTHI, assuming that the transducer translates incident positions by 50?m when two beamlines of pulse inversion pair are acquired. CPI-CTHI is implemented for a proto-typed intravascular ultrasound scanner capable of combined data acquisition in real-time. A wire phantom study shows that CPI-CTHI has a 12dB lower range side lobe level and a 7dB higher echo signal to noise ratio than PI-CTHI, while the lateral resolution and side lobe level are 50?m finer and -3dB less than fundamental chirp coded excitation imaging respectively. Ex vivo scanning of a rabbit trachea demonstrates that CPI-CTHI is capable of visualizing blood vessels as small as 200?m in diameter with 6dB better tissue contrast than either PI-CTHI or fundamental chirp coded excitation imaging. These results clearly indicate that CPI-CTHI may enhance tissue contrast with less range side lobe level than PI-CTHI. PMID:22871273

Park, Jinhyoung; Li, Xiang; Zhou, Qifa; Shung, K Kirk

2012-07-21

78

Left Ventricular Myocardial Impairment in Subclinical Hypothyroidism Assessed by a New Ultrasound Tool: Pulsed Tissue Doppler  

Microsoft Academic Search

Pulsed tissue Doppler (TD) is a new ultrasound tool that al- lows quantification of myocardial regional wall motion. To investigate the cardiac effects of subclinical hypothyroidism (SH), the present study assessed left ventricular (LV) myocar- dial regional function in SH by pulsed TD. Twenty women with SH and 20 healthy women underwent standard Doppler echocardiograms and pulsed TD, placing a

GIOVANNI VITALE; MAURIZIO GALDERISI; GELSY ARIANNA LUPOLI; ALDO CELENTANO; ILARIA PIETROPAOLO; NICOLA PARENTI; ORESTE DE DIVITIIS; GIOVANNI LUPOLI

79

In vivo tissue sampling of embryonic resorption sites using ultrasound guided biopsy  

Microsoft Academic Search

In the polytocous European brown hare (Lepus europaeus) more than 23% of all successful implantations undergo embryonic resorption. The objective of the study was to establish a minimally invasive ultrasound guided biopsy technique to collect embryonic resorption tissue in vivo. The sampled material was genetically analysed to determine paternity and the sex of the embryo. Female hares were either mated

K. Schroeder; B. Drews; K. Roellig; B. R. Menzies; F. Goeritz; T. B. Hildebrandt

2011-01-01

80

A Targeting Method Based on Acoustic Backscatter for Treatment Planning in Tissue Ablation Using Focused Ultrasound  

Microsoft Academic Search

High-intensity focused ultrasound (HIFU) is a therapeutic modality that can produce coagulative necrosis in biological tissue, noninvasively. This technique requires the determination of the focus of a HIFU transducer before treatment. We investigated a method to localize the focus based on the change in radio-frequency (RF) signal at HIFU intensity levels below the threshold for tissue damage. 2-D RF data

Shahram Vaezy

2010-01-01

81

Stochastic modeling of tissue microstructure for high-frequency ultrasound imaging simulations  

NASA Astrophysics Data System (ADS)

High-frequency (> 20 MHz) ultrasound images of preclinical tumor models are sensitive to changes in tissue microstructure that accompany tumor progression and treatment responses, but the relationships between tumor microanatomy and high-frequency ultrasound backscattering are incompletely understood. Computational models of tissue microstructure can be employed with ultrasound propagation simulators to investigate these relationships. This paper introduces a three-dimensional microanatomical model in which tissue is treated as a population of stochastically positioned spherical cells embedded in a homogeneous extracellular matrix, where each cell consists of a spherical nucleus surrounded by homogeneous cytoplasm. The model is used to represent the microstructure of both healthy mouse liver and experimental liver metastasis. Normal and cancerous tissue specimens stained with DAPI and H&E are digitized at 20× magnification and analyzed to specify values of the model parameters. Simulated healthy and tumor tissues are initialized based on the ratio of cell to nucleus diameter and the nuclear volume fraction and size distribution estimated by stereological analysis of the normal and cancerous liver specimens, respectively. For each simulated tissue, the spatial organization of cells is controlled by a Gibbs-Markov point process. The parameters of the Gibbs-Markov process are tuned to accurately reproduce the number density and distribution of center-to-center spacing of nuclei in the DAPI-stained slides of the corresponding experimental tissue specimen. The morphological variations that can be produced by changing the model parameters are expected to be sufficient to represent the microstructural changes during tumor progression that are the most significant determinants of high-frequency ultrasound backscattering.

Daoud, Mohammad I.; Lacefield, James C.

2009-02-01

82

Controlled tissue emulsification produced by high intensity focused ultrasound shock waves and millisecond boiling  

PubMed Central

In high intensity focused ultrasound (HIFU) applications, tissue may be thermally necrosed by heating, emulsified by cavitation, or, as was recently discovered, emulsified using repetitive millisecond boiling caused by shock wave heating. Here, this last approach was further investigated. Experiments were performed in transparent gels and ex vivo bovine heart tissue using 1, 2, and 3 MHz focused transducers and different pulsing schemes in which the pressure, duty factor, and pulse duration were varied. A previously developed derating procedure to determine in situ shock amplitudes and the time-to-boil was refined. Treatments were monitored using B-mode ultrasound. Both inertial cavitation and boiling were observed during exposures, but emulsification occurred only when shocks and boiling were present. Emulsified lesions without thermal denaturation were produced with shock amplitudes sufficient to induce boiling in less than 20 ms, duty factors of less than 0.02, and pulse lengths shorter than 30 ms. Higher duty factors or longer pulses produced varying degrees of thermal denaturation combined with mechanical emulsification. Larger lesions were obtained using lower ultrasound frequencies. The results show that shock wave heating and millisecond boiling is an effective and reliable way to emulsify tissue while monitoring the treatment with ultrasound.

Khokhlova, Tatiana D.; Canney, Michael S.; Khokhlova, Vera A.; Sapozhnikov, Oleg A.; Crum, Lawrence A.; Bailey, Michael R.

2011-01-01

83

Localized Ablation of Thyroid Tissue by High-Intensity Focused Ultrasound: an Alternative to Surgery?  

NASA Astrophysics Data System (ADS)

PURPOSE: The aim of this study was to evaluate the feasibility of using a High-intensity focused ultrasound (HIFU) device to obtain a localised destruction of the thyroid with no damage to adjacent tissues. MATERIALS AND METHODS: The ewe model was used because its thyroid gland is easily accessible with ultrasound. The animals were anaesthetised with 10 mg / kg IV injection of Penthothal. The HIFU pulses were generated by a 3-MHz spherical transducer under ultrasound guidance. Macroscopic and microscopic tissue lesions were identified after formalin fixation of the anterior part of the ewe's neck. RESULTS: After determining the optimal instrument settings to obtain localized thyroid ablation, the repeatability of the method was evaluated using a HIFU prototype designed specifically for human use: in 13 ewes (26 treated lobes), an average of 20 (range: 14-27) ultrasound pulses (pulse duration: 3 s) per lobe covering a mean volume of 0.5 cm3 (range: 0.3-0.7 cm3) were delivered. The ewes were sacrificed 2-5 weeks after treatment delivery. No damage to the nerves, trachea, esophagus or muscle was observed. Only 3 ewes suffered superficial skin burns. The desired thyroid lesions were obtained in 25/26 treated lobes, as demonstrated by fibrotic tissues, which replaced necrotic areas. CONCLUSION: These results obtained in the ewe model show that thyroid lesions of defined volume can be induced safely and suggest that the HIFU device is now ready for human trials.

Esnault, Olivier; Franc, Brigitte; Chapelon, Jean-Yves; Lacoste, Francois

2006-05-01

84

Diffraction based acoustic measurements of tissue-mimicking ultrasound phantoms  

NASA Astrophysics Data System (ADS)

Traditional methods of ultrasonic materials characterization are commonly used in industrial and medical settings. These methods generally require a priori knowledge of material thickness or sound propagation speed. New methods of materials characterization have been developed at MU to estimate sound propagation speed and materials thickness simultaneously. This research project details the application of these new methods to tissue-mimicking materials produced at MU. Research completed to support this work includes the production of tissue-mimicking materials, theoretical development of new methods, application of new methods to tissue-mimicking materials, comparison of results from new methods and traditional methods, and estimation of acoustic attenuation using multiple traditional methods. As a result of this research, a series of tissue-mimicking phantoms were produced for the first time at MU. The results of this research also showed that new methods of materials characterization could be applied successfully to tissue-mimicking materials. Likewise, propagation speed estimations obtained from new methods compared very well with results obtained using traditional methods. In most cases the difference between the measurements was less than 5 percent, while in no case did the difference exceed 10 percent. Estimates of acoustic attenuation were also made using two traditional methods. Comparison of attenuation estimates revealed differences that were generally smaller than 20 percent. The results of this research show that new methods of estimating sound propagation speed and material thickness can be applied to tissue-mimicking materials. With further research it is likely that these methods could be applied in medical imaging equipment to improve the quality of patient care.

Schupp, Nicholas D.

85

Noninvasive surgery of prostate tissue by high-intensity focused ultrasound: an updated report  

NASA Astrophysics Data System (ADS)

High Intensity Focused Ultrasound (HIFU) has been clinically used for the treatment of benign prostatic hyperplasia (BPH) and it is experimentally applied for the treatment of localized prostate caner (PC). Recent advances in the transducer material and technology have permitted to combine the ultrasound visualization capability and HIFU on the same ceramic crystal. Also, the transducer efficiency has increased to a level that a smaller size intracavity probe can be made to produce sufficient acoustic power required for the focused ultrasound surgery of the prostate. Using this technology, 4 MHz mechanically scanning transrectal ultrasound probes has been designed. The transrectal probes are used with Sonablate (SB-200, manufactured by Focus Surgery, Inc., Indianapolis, IN) device. The SB-200 produces both transverse and longitudinal images of the prostate. The transverse and longitudinal images are used for selection of tissue volume, treatment planning and monitoring of tissue during the HIFU treatment cycle. The paper reviews the present operation of the device and recent clinical protocol that has improved efficiency, efficacy and safety of the device. The two years follow-up clinical results from the multi-site US Pilot Study (USPS) and The Male Health Centre are compared with the Kitasato-study (Kitasato School of Medicine, Sagamihara, Japan).

Sanghvi, Narendra T.; Syrus, J.; Foster, Richard S.; Bihrle, Richard; Casey, Richard W.; Uchida, Toyoak

2000-05-01

86

Validation of high-frequency ultrasound measurements of tissue layer thickness  

NASA Astrophysics Data System (ADS)

High-frequency ultrasound imaging enables nondestructive measurement of layer thickness in tissue specimens. These measurements are valuable for mechanical testing of soft biomaterials. This paper demonstrates a method for assessing the accuracy of high-resolution ultrasonic thickness estimates. Three-dimensional images of six porcine aortic valve cusps were acquired in vitro using a 40 MHz ultrasound system with 40×80×80 ?m3 spatial resolution. The cusps were then frozen in liquid nitrogen, sectioned into 10-?m slices, and micrographs of one slice from each specimen were acquired at 4× magnification. The two-dimensional micrographs were registered to the three-dimensional ultrasound images using a cross-correlation method. The boundaries of the fibrosa, spongiosa, and ventricularis layers were segmented in both sets of images using an active contour model. The average thicknesses of the tissue layers in the registered images were estimated and the absolute differences of the optical and ultrasonic estimates were computed. The absolute differences were 55.8+/-22.6 ?m (mean +/- standard deviation), 23.5+/-14.3 ?m, and 22.7+/-17.2 ?m for the fibrosa, spongiosa, and ventricularis, respectively. The measurement differences are comparable to the axial resolution of the ultrasound system and are not significant as determined by t-tests (p>0.30 for each layer).

Qiu, Qiang; Dunmore-Buyze, Joy; Boughner, Derek R.; Lacefield, James C.

2005-04-01

87

Ultrasound phase-contrast transmission imaging of localized thermal variation in a breast tissue model  

NASA Astrophysics Data System (ADS)

The present numeric study examines an ultrasound phase contrast method for imaging localized temperature rises in tissue, such as heating experienced in thermal ablation treatments. We tested the method's ability to produce thermal images by simulating the signal from a planar ultrasound source directed through tissue containing skin, fat, and muscle layers. Phase-contrast imaging only requires phase shifts a fraction of a wavelength for detection, thus we tested for the feasibility of imaging at low (submegahertz) frequencies, allowing greater depth penetration and reduced scattering away from the image plane. The tradeoff for lower frequencies was a reduced spatial resolution. It was therefore necessary to determine the lowest possible frequency that could still provide information about the tissue structure and information about the temperature rise in the heated volume. After studying a tomographically reconstructed 4-mm cylindrical heated region in a 100-mm-thick section breast tissue model, thermal effects were detected at frequencies as low as 0.4 MHz, which allowed reconstruction resolution of about 2 mm2 over the image plane. This method may have applications for example in controlling focused ultrasound surgery of breast.

Clement, Greg; Hynynen, Kullervo

2003-04-01

88

Ultrasound  

MedlinePLUS

... couldn't see my baby at my 7 week ultrasound. Why? At the 7th week of pregnancy, your baby is about ½ an ... 1 in 120 pregnancies at 15 to 20 weeks gestation. Most disappear during pregnancy or within several ...

89

Ultrasound-based transient elastography compared to magnetic resonance elastography in soft tissue-mimicking gels.  

PubMed

Ultrasound-based transient elastography (TE) and magnetic resonance elastography (MRE) are increasingly used methods for the clinical evaluation of soft tissue mechanical properties and their alteration under diseased conditions. This study proposes a comparison between magnetic resonance elastography (MRE) and ultrasound-based transient elastography (TE). Both methods were tested on the same soft tissue-mimicking gels in a common frequency range in order to allow for direct quantitative comparison. For the four gels tested, relatively good agreement was found between the shear moduli measured by both methods, with an averaged relative difference of 23%. This study demonstrates that under the assumption of homogeneous media that are significantly more elastic than viscous, quantitative results obtained by both methods are comparable. PMID:19887718

Oudry, Jennifer; Vappou, Jonathan; Choquet, Philippe; Willinger, Rémy; Sandrin, Laurent; Constantinesco, André

2009-11-04

90

Tissue motion and strain in the human brain assessed by intraoperative ultrasound in glioma patients.  

PubMed

The objective of the study was to investigate tissue motion and strain imposed by cardiovascular pulsation in pathologic and normal brain parenchyma, as quantified from in vivo ultrasound data. Ultrasound acquired during surgery of 16 patients with glial tumors was retrospectively processed and analyzed. The tissue velocity was quantified at depths of 1cm, 2cm and 3cm from brain cortex to investigate spatial dependency with depth. Comparison of strain and velocity in tumor and adjacent normal parenchyma was performed by selecting two regions-of-interest in the hyperechoic tumor and two regions in the low-echogenic areas interpreted as mainly normal tissue with some degree of tumor cell infiltration. The absolute maximum tissue velocity is seen to increase with increasing depths in 14 of 16 cases (87.5%). The maximum tissue velocities in the four regions close to the ultrasound visible tumor border are not statistically different (p=0.163 to p=0.975). The strain magnitudes are significantly higher in the regions with expected normal brain parenchyma than in regions with expected glial tumor tissue, both for the two regions being closest to the tumor border (p=0.0004) and for the two regions further away from the tumor border (p=0.0009). We conclude that the velocity of the brain parenchyma imposed by arterial pulsation during a cardiac cycle is generally increasing with increasing depth from cortex. The maximum velocity appears to be similar in regions with expected normal brain and tumor tissue, thus, does not seem to be affected by pathology. Strain magnitude is, however, a suitable parameter for discrimination of glial tumor and normal brain parenchyma. (E-mail: Tormod.Selbekk@sintef.no). PMID:19854562

Selbekk, Tormod; Brekken, Reidar; Solheim, Ole; Lydersen, Stian; Hernes, Toril A N; Unsgaard, Geirmund

2010-01-01

91

Ultrasound Myocardial Tissue Characterization by Integrated Backscatter in Children Treated with Anthracyclines  

Microsoft Academic Search

.   The objective of our study was to evaluate integrated backscatter (IBS) measurement, an ultrasound method of myocardial tissue\\u000a characterization, in children receiving cardiotoxic anthracyclines for malignancy. Myocardial injury is known to diminish\\u000a the normal cyclic variation of IBS (CVIBS) during the cardiac cycle. We used a cross-sectional, case-controlled study of children\\u000a receiving anthracyclines and serial, prospective observation in a

M. B. Goens; S. S. Karr; N. Seibel; G. R. Martin

1999-01-01

92

Cavitation Detection in Ex Vivo Bovine Liver Tissue Exposed to High Intensity Focued Ultrasound (HIFU)  

Microsoft Academic Search

A study of the feasibility of detecting broadband high frequency emissions (6-12 MHz) generated by acoustic cavitation activity during clinical high intensity focused ultrasound (HIFU) exposures are presented. The ability to monitor acoustic emissions, drive power fluctuations and audible (1-20 kHz) emissions is demonstrated in ex vivo tissue, and the utility of active cavitation detection (ACD) is shown. It is

James Mclaughlan; Ian Rivens; Gail Ter Haar

2007-01-01

93

Thermal contribution of compact bone to intervening tissue-like media exposed to planar ultrasound  

NASA Astrophysics Data System (ADS)

The presence of bone in the ultrasound beam path raises concerns, both in diagnostic and therapeutic applications, because significant temperature elevations may be induced at nearby soft tissue-bone interfaces due the facts that ultrasound is (i) highly absorbed in bone and (ii) reflected at soft tissue-bone interfaces in various degrees depending on angle of incidence. Consequently, in ultrasonic thermal therapy, the presence of bone in the ultrasound beam path is considered a major disadvantage and it is usually avoided. However, based on clinical experience and previous theoretical studies, we hypothesized that the presence of bone in superficial unfocused ultrasound hyperthermia can actually be exploited to induce more uniform and enhanced (with respect to the no-bone situation) temperature distributions in superficial target volumes. In particular, we hypothesize that the presence of underlying bone in superficial target volume enhances temperature elevation not only by additional direct power deposition from acoustic reflection, but also from thermal diffusion from the underlying bone. Here we report laboratory results that corroborate previous computational studies and strengthen the above-stated hypothesis. Three different temperature measurement techniques, namely, thermometric (using fibre-optic temperature probes), thermographic (using an infrared camera) and magnetic resonance imaging (using proton resonance frequency shifts), were used in high-power short-exposure, and in low-power extended-exposure, experiments using a 19 mm diameter planar transducer operating at 1.0 and 3.3 MHz (frequencies of clinical relevance). The measurements were performed on three technique-specific phantoms (with and without bone inclusions) and experimental set-ups that resembled possible superficial ultrasound hyperthermia clinical situations. Results from all three techniques were in general agreement and clearly showed that significantly higher heating rates (greater than fourfold) were induced in soft tissue-like phantom materials adjacent (within ~5 mm) to a bovine bone as compared to similar experiments without bone inclusions. For low-power long-exposure experiments, where thermal conduction effects are significant, the thermal impact of bone reached at distances >10 mm from the bone surface (upstream of the bone). Therefore, we hypothesize that underlying bone exposed to planar ultrasound hyperthermia creates a high-temperature thermal boundary at depth that compensates for beam attenuation, thus producing more uniform temperature distribution in the intervening tissue layers. With appropriate technology, this finding may lead to improved thermal doses in superficial treatment sites such as the chest wall and the head/neck.

Moros, Eduardo G.; Novak, Petr; Straube, William L.; Kolluri, Prashant; Yablonskiy, Dmitriy A.; Myerson, Robert J.

2004-03-01

94

Numerical Simulation of Temperature Elevation in Soft Tissue by High Intensity Focused Ultrasound  

NASA Astrophysics Data System (ADS)

In focused ultrasound surgery, high intensity focused ultrasound (HIFU) can be used to destroy pathological tissue deep inside the body without any damage to the surrounding normal tissue. This noninvasive technique has been used to treat malignant tumors of the liver, prostate, kidney, and benign breast tumors via a percutaneous or transrectal approach without the need for general anaesthesia. In the present study, a finite element method was used for the simulation of temperature elevation in soft tissue by HIFU. First, the HIFU field was modeled using the Westervelt equation for the propagation of finite-amplitude sound in a thermoviscous fluid in order to account for the effects of diffraction, absorption, and nonlinearity. Second, the Pennes bioheat transfer equation was used to predict the temperature elevation in soft tissue by HIFU. In order to verify the numerical simulation, the simulated temperature elevation at the focus in a tissue-mimicking phantom was compared with the measurements, using a concave focused transducer with a focal length of 62.6 mm, a radius of 35.0 mm, and a center frequency of 1.1 MHz.

Lee, Kang Il; Sim, Imbo; Kang, Gwan Suk; Choi, Min Joo

95

A tissue mimicking polyacrylamide hydrogel phantom for visualizing thermal lesions generated by high intensity focused ultrasound.  

PubMed

An optically transparent tissue-mimicking (TM) phantom whose acoustic properties are close to those of tissue was constructed for visualizing therapeutic effects by high intensity focused ultrasound (HIFU). The TM phantom was designed to improve a widely used standard bovine serum albumin (BSA) polyacrylamide hydrogel (PAG), which attenuated ultrasound far less than tissue and, unlike tissue, did not scatter ultrasound. A modified recipe has been proposed in the study by adding scattering glass beads with diameters of 40-80 ?m (0.002% w/v) and by raising the concentration of acrylamide (30% v/v). The TM BSA-PAG constructed has an acoustic impedance of 1.67 MRayls, a speed of sound of 1576 m/s, an attenuation coefficient of 0.52 dB/cm at 1 MHz, a backscattering coefficient of 0.242 × 10(-3) 1/sr/cm at 1 MHz and a nonlinear parameter (B/A) of 5.7. These parameters are close to those of liver. The thermal and optical properties are almost the same as the standard BSA-PAG. The characteristic features of the thermal lesions by HIFU were observed to be more accurately visualized in the TM BSA-PAG than in the standard BSA-PAG. In conclusion, the proposed TM BSA-PAG acoustically mimics tissue better than the standard BSA-PAG and is expected to be preferentially used for assuring if a clinical HIFU device produces the thermal lesion as planned. PMID:23312531

Choi, Min Joo; Guntur, Sitaramanjaneya Reddy; Lee, Kang Il; Paeng, Dong Guk; Coleman, Andrew

2013-01-09

96

Ultrasound evidence of altered lumbar connective tissue structure in human subjects with chronic low back pain  

PubMed Central

Background Although the connective tissues forming the fascial planes of the back have been hypothesized to play a role in the pathogenesis of chronic low back pain (LBP), there have been no previous studies quantitatively evaluating connective tissue structure in this condition. The goal of this study was to perform an ultrasound-based comparison of perimuscular connective tissue structure in the lumbar region in a group of human subjects with chronic or recurrent LBP for more than 12 months, compared with a group of subjects without LBP. Methods In each of 107 human subjects (60 with LBP and 47 without LBP), parasagittal ultrasound images were acquired bilaterally centered on a point 2 cm lateral to the midpoint of the L2-3 interspinous ligament. The outcome measures based on these images were subcutaneous and perimuscular connective tissue thickness and echogenicity measured by ultrasound. Results There were no significant differences in age, sex, body mass index (BMI) or activity levels between LBP and No-LBP groups. Perimuscular thickness and echogenicity were not correlated with age but were positively correlated with BMI. The LBP group had ~25% greater perimuscular thickness and echogenicity compared with the No-LBP group (ANCOVA adjusted for BMI, p < 0.01 and p < 0.001 respectively). Conclusion This is the first report of abnormal connective tissue structure in the lumbar region in a group of subjects with chronic or recurrent LBP. This finding was not attributable to differences in age, sex, BMI or activity level between groups. Possible causes include genetic factors, abnormal movement patterns and chronic inflammation.

2009-01-01

97

Tomographic reconstruction of tissue properties and temperature increase for high-intensity focused ultrasound applications.  

PubMed

The acoustic and thermal properties as well as the temperature change within a tissue volume during high-intensity focused ultrasound ablation are critically important for treatment planning and monitoring. Described in this article is a tomographic reconstruction method used to determine the tissue properties and increase in temperature in a 3-D volume. On the basis of the iterative finite-element solution to the bioheat equation coupled with Tikhonov regularization techniques, our reconstruction algorithm solves the inverse problem of bioheat transfer and uses the time-dependent temperature measured on a tissue surface to obtain the acoustic absorption coefficient, thermal diffusivity and temperature increase within the subsurface volume. Numerical simulations were performed to validate the reconstruction algorithm. The method was initially conducted in ex vivo experiments in which time-dependent temperature on a tissue surface was measured using high-resolution, non-invasive infrared thermography. PMID:23849388

Yin, Lu; Gudur, Madhu Sudhan Reddy; Hsiao, Yi-Sing; Kumon, Ronald E; Deng, Cheri X; Jiang, Huabei

2013-07-09

98

Ultrasound-modulated optical tomography of biological tissue by use of contrast of laser speckles  

NASA Astrophysics Data System (ADS)

Ultrasound-modulated optical tomography based on the measurement of laser-speckle contrast was investigated. An ultrasonic beam was focused into a biological-tissue sample to modulate the laser light passing through the ultrasonic column inside the tissue. The contrast of the speckle pattern formed by the transmitted light was found to depend on the ultrasonic modulation and could be used for imaging. Variation in the speckle contrast reflected optical inhomogeneity in the tissue. With this technique, two-dimensional images of biological-tissue samples of as much as 25 mm thick were successfully obtained with a low-power laser. The technique was experimentally compared with speckle-contrast-based, purely optical imaging and with parallel-detection imaging techniques, and the advantages over each were demonstrated.

Li, Jun; Ku, Geng; Wang, Lihong V.

2002-10-01

99

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

NASA Astrophysics Data System (ADS)

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.

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

2009-09-01

100

Trans-urethral ultrasound (TUUS) imaging for visualization and analysis of the prostate and associated tissues  

NASA Astrophysics Data System (ADS)

Accurate assessment of pathological conditions in the prostate is difficult. Screening methods include palpation if the prostate gland, blood chemical testing, and diagnostic imaging. Trans-rectal Ultrasound (TRUS) is commonly used for the assessment of pathological conditions, however, TRUS is severely constrained by the relative distal location of the imaging probe. Trans-urethral Ultrasound (TUUS) may overcome some limitations of TRUS. A TUUS catheter was used to image the prostate, rectum, bladder, ureter, neuro-vascular bundles, arteries, and surrounding tissue. In addition, 360 degrees rotational scans were recorded for reconstruction into 3D volumes. Segmentation was challenging, however, new techniques such as active contour methods show potential. 3D visualizations, including both volume and surface rendering, were provided to clinicians off-line. On-line 3D visualization techniques are currently being developed. Potential applications of TUUS include: prostate cancer diagnosis and staging as well as image guided biopsy and therapy.

Holmes, David R.; Robb, Richard A.

2000-04-01

101

High frequency ultrasound measurements of the attenuation and backscatter from biological tissues  

NASA Astrophysics Data System (ADS)

There are now diagnostic ultrasonic imaging devices that operate at very high frequencies (VHF) of 20 MHz and beyond for clinical applications in ophthalmology, dermatology, and vascular surgery. To be able to better interpret these images and to further the development of these devices, knowledge of ultrasonic attenuation and scattering of biological tissues in this high frequency range is crucial. Though currently VHF ultrasound is applied mostly to the eye and skin tissue, in this thesis, VHF experiments were performed on porcine red blood cell suspensions and bovine myocardium, liver, and kidney because these tissues are easy to obtain, are similar in structure to their human counterparts and have been used in ultrasound experiments by many investigators but in a lower frequency range. Attenuation and backscatter coefficients of porcine blood and bovine tissues were measured, respectively, using substitution methods. Unfocused and focused transducers were employed in the experiments and corresponding results were compared. This dissertation presents the results of measurements of acoustic attenuation and backscatter from various biological materials (bovine myocardium, liver, and kidney, and porcine blood) in a wide frequency range (10 to 90 MHz) and compares them to previous lower frequency results. Based on the methods used to calculate the acoustic parameters, the frequency limits of the measurements are also defined.

Maruvada, Subha

102

Development of a portable 3D ultrasound imaging system for musculoskeletal tissues.  

PubMed

3D ultrasound is a promising imaging modality for clinical diagnosis and treatment monitoring. Its cost is relatively low in comparison with CT and MRI, no intensive training and radiation protection is required for its operation, and its hardware is movable and can potentially be portable. In this study, we developed a portable freehand 3D ultrasound imaging system for the assessment of musculoskeletal body parts. A portable ultrasound scanner was used to obtain real-time B-mode ultrasound images of musculoskeletal tissues and an electromagnetic spatial sensor was fixed on the ultrasound probe to acquire the position and orientation of the images. The images were digitized with a video digitization device and displayed with its orientation and position synchronized in real-time with the data obtained by the spatial sensor. A program was developed for volume reconstruction, visualization, segmentation and measurement using Visual C++ and Visualization toolkits (VTK) software. A 2D Gaussian filter and a Median filter were implemented to improve the quality of the B-scan images collected by the portable ultrasound scanner. An improved distance-weighted grid-mapping algorithm was proposed for volume reconstruction. Temporal calibrations were conducted to correct the delay between the collections of images and spatial data. Spatial calibrations were performed using a cross-wire phantom. The system accuracy was validated by one cylinder and two cuboid phantoms made of silicone. The average errors for distance measurement in three orthogonal directions in comparison with micrometer measurement were 0.06+/-0.39, -0.27+/-0.27, and 0.33+/-0.39 mm, respectively. The average error for volume measurement was -0.18%+/-5.44% for the three phantoms. The system has been successfully used to obtain the volume images of a fetus phantom, the fingers and forearms of human subjects. For a typical volume with 126 x 103 x 109 voxels, the 3D image could be reconstructed from 258 B-scans (640 x 480 pixels) within one minute using a portable PC with Pentium IV 2.4 GHz CPU and 512 MB memories. It is believed that such a portable volume imaging system will have many applications in the assessment of musculoskeletal tissues because of its easy accessibility. PMID:15556650

Huang, Q H; Zheng, Y P; Lu, M H; Chi, Z R

2005-01-01

103

Real-time 3D target tracking in MRI guided focused ultrasound ablations in moving tissues.  

PubMed

Magnetic resonance imaging-guided high intensity focused ultrasound is a promising method for the noninvasive ablation of pathological tissue in abdominal organs such as liver and kidney. Due to the high perfusion rates of these organs, sustained sonications are required to achieve a sufficiently high temperature elevation to induce necrosis. However, the constant displacement of the target due to the respiratory cycle render continuous ablations challenging, since dynamic repositioning of the focal point is required. This study demonstrates subsecond 3D high intensity focused ultrasound-beam steering under magnetic resonance-guidance for the real-time compensation of respiratory motion. The target is observed in 3D space by coupling rapid 2D magnetic resonance-imaging with prospective slice tracking based on pencil-beam navigator echoes. The magnetic resonance-data is processed in real-time by a computationally efficient reconstruction pipeline, which provides the position, the temperature and the thermal dose on-the-fly, and which feeds corrections into the high intensity focused ultrasound-ablator. The effect of the residual update latency is reduced by using a 3D Kalman-predictor for trajectory anticipation. The suggested method is characterized with phantom experiments and verified in vivo on porcine kidney. The results show that for update frequencies of more than 10 Hz and latencies of less then 114 msec, temperature elevations can be achieved, which are comparable to static experiments. PMID:20878763

Ries, Mario; de Senneville, Baudouin Denis; Roujol, Sébastien; Berber, Yasmina; Quesson, Bruno; Moonen, Chrit

2010-09-27

104

Ultrasound  

MedlinePLUS

... technician or doctor moves a device called a transducer over part of your body. The transducer sends out sound waves, which bounce off the tissues inside your body. The transducer also captures the waves that bounce back. The ...

105

Application of the ultrasound hyperthermia model for a multi-layered tissue system  

NASA Astrophysics Data System (ADS)

This work models the thermal effect of several planar transducers targeting the tumour interactively in a ceramics-coupling-skin-muscle-tumour system. The most important inputs of the model include the following: emitted electric output, J/s; mechanical efficiency, %; number of transducers, pieces; surface area of the transducer, m2; area, m2 and temperature, K of the cooling surface, attenuation coefficients, Np/cm MHz; specific heats, J/gK; densities, g/cm3; heat conductivities, J/msK; sound velocities m/s; flow rate of blood in the tissues, ml/gtissue/min; sound path in the tissues and in the blood flowing through the tissues, m. From the inputs, a number of intermediate data are determined, e.g. the geometry of the irradiated bodies that are in the path of ultrasound, acoustic hardness, Pas/m; sound reflection and sound transmission occurring at the interfaces, Np; heat exchanger wall thickness of the irradiated bodies, m; heat dissipation and heat exchanger surface areas, m2; flow rate of blood in the tissues located in the path of ultrasound, ml/tissue mass in g/min; and the sound attenuation of the tissues, Np. The amount of generated heat, K/s decreased by the heat energy transported, J/s to the surrounding tissues by blood and heat conductivity, and the actual temperature, K of the irradiated tissue are the output parameters calculated by the model. The output results are available in the form of functions. The expected temperature of the target area, K can be set to either the denaturation temperature or to the respiratory decomposition temperature (43.5°C) without damaging the surrounding tissues by setting in the following parameters properly: electric output power, W; the number and surface area, m2 of the transducers; the area, m2 and temperature, K of the cooling surfaces. After further development, the model will be suitable for handling more than three tissue layers, increased blood flow rates different angles of incidence, and tumours having different geometric shape.

Lörincz, A.

2004-01-01

106

Harmonic Band Spectrum Analysis of Backscattered Ultrasound from Lesioned and Normal Tissue  

NASA Astrophysics Data System (ADS)

HIFU dose curves (lesion size vs. exposure parameters) exhibit scatter because of local variations in the acoustic properties of tissue. Therefore, clinical applications of HIFU, such as cardiac and cancer ablation, will benefit from the ability to distinguish treated from normal tissue, which can provide the surgeon with lesion monitoring. However, HIFU lesions, especially protein-denaturing lesions (PDLs), may be difficult to visualize with conventional B-mode ultrasound. In this study, spectrum analysis of backscattered radiofrequency (RF) ultrasound was successful in imaging lesions. HIFU lesions were formed at 5 MHz for various intensities and durations in model tissues including degassed chicken breast in vitro, fresh rabbit liver ex vivo, and canine cardiac left ventricle in vivo. The tissues were scanned pre- and post-exposure using confocal array and single-element diagnostic probes incorporated into the HIFU transducer assembly. The diagnostic probes were excited with a monocycle pulse under conditions previously shown to generate a second harmonic comparable in amplitude to the fundamental, and RF echo-signal data were recorded. In an alternate set, the therapy and diagnostic transducers were operated pitch-catch, with the therapy transducer sending out a series of 0.4 ms pulses and the diagnostic transducer in passive receive mode. Spectrum analysis of the RF data was performed separately on first (fundamental) and second harmonic frequency bands. Linear regression fits to spectra computed for sliding regions-of-interest yielded 3 parameters: midband fit (integrated backscatter), y-intercept and slope; grayscale images were produced for each parameter. Differences among the B-mode and parameter images, and between the lesion site and adjacent untreated tissues, were characterized statistically. The results indicate that midband fit images of both the fundamental and harmonic offer improved contrast and lateral resolution compared to conventional images. PDLs and bubbly lesions that are not clearly visible in B-mode images can be imaged with harmonic band spectrum analysis.

Muratore, Robert; Lizzi, Frederic L.; Silverman, Ronald H.

2006-05-01

107

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

PubMed

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 ?m and 40 ?m, 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 error of 3.6% in lesion estimation. This study demonstrated the feasibility of a high-resolution hybrid imaging technique to diagnose atherosclerosis and characterize plaque components in mouse. In the future, it can be easily implemented on commercial ultrasound systems and eventually translated into clinics as a screening tool for atherosclerosis and the assessment of vulnerable plaques. PMID:23218908

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

2012-11-16

108

Treatment of sialorrhoea with ultrasound guided botulinum toxin type A injection in patients with neurological disorders  

Microsoft Academic Search

OBJECTIVESTo investigate the safety and efficacy of ultrasound guided botulinum toxin type A (BTX-A) injections into salivary glands for the treatment of sialorrhoea in patients with neurological disorders.METHODSThe parotid and submandibular glands of 10 patients were injected with BTX-A using ultrasound guidance. Before injection, the baseline rate of salivation was assessed using a visual analogue scale. Postinjection, assessments were repeated

M Porta; M Gamba; G Bertacchi; P Vaj

2001-01-01

109

Optical measurement of adipose tissue thickness and comparison with ultrasound, magnetic resonance imging, and callipers  

NASA Astrophysics Data System (ADS)

Near-infrared spectroscopy is used to quantify the subcutaneous adipose tissue thickness (ATT) over five muscle groups (vastus medialis, vastus lateralis, gastrocnemius, ventral forearm and biceps brachii muscle) of healthy volunteers (n=20). The optical lipid signal (OLS) was obtained from the second derivative of broad band attenuation spectra and the lipid absorption peak (?=930 nm). Ultrasound and MR imaging as well as mechanical calliper readings were taken as reference methods. The data show that the OLS is a good predictor for ATT (<16 mm) with absolute and relative errors of <0.8 mm and <24%, respectively. The optical method compares favourably with calliper reading. The finding of a non-linear relationship of optical signal vs. ultrasound is explained by a theoretical two-layer model based on the diffusion approximation for the transport of photons. The crosstalk between the OLS and tissue hemoglobin concentration changes during an incremental cycling exercise was found to be small, indicating the robustness of OLS. Furthermore, the effect of ATT on spatially-resolved spectroscopy measurements is shown to decrease the calculated muscle hemoglobin concentration and to increase oxygen saturation.

Geraskin, Dmitri; Boeth, Heide; Kohl-Bareis, Matthias

2009-07-01

110

Non-Invasive Breast Tissue Characterization Using Ultrasound Speed and Attenuation  

NASA Astrophysics Data System (ADS)

TechniScan Medical Systems, Inc. is using novel inverse scattering methods to provide a unique method for calculating ultrasound characteristics of speed and attenuation of sound traveling through human tissue. In this paper we describe basic system parameters and results of the first in vivo patient studies. It is concluded that this novel inverse scattering method provides a unique method for noninvasive breast tissue characterization that could assist physicians in assigning probability of cancer to breast abnormalities identified but not resolved with currently available imaging techniques. This application could have a major impact on patient management decisions and has the potential to reduce the number of currently unavoidable breast biopsies that result in a benign outcome

Johnson, S. A.; Abbott, T.; Bell, R.; Berggren, M.; Borup, D.; Robinson, D.; Wiskin, J.; Olsen, S.; Hanover, B.

111

Changes in backscatter of liver tissue due to thermal coagulation induced by focused ultrasound.  

PubMed

Ultrasonic imaging has advantages in its self-consistency in guiding and monitoring ultrasonic treatment such as high-intensity focused ultrasound (HIFU) treatment. Changes in ultrasonic backscatter of tissues due to HIFU treatment have been observed, but their mechanism is still under discussion. In this paper, ultrasonic backscatter of excised and degassed porcine liver tissue was observed before and after HIFU exposure using a diagnostic scanner, and its acoustic impedance was mapped using an ultrasonic microscope. The histology of its pathological specimen was also observed using an optical microscope. The observed decrease in backscatter intensity due to HIFU exposure was consistent with a spatial Fourier analysis of the histology, which also showed changes due to the exposure. The observed increase in acoustic impedance due to the exposure was also consistent with the histological change assuming that the increase was primarily caused by the increase in the concentration of hepatic cells. PMID:23927213

Shishitani, Takashi; Matsuzawa, Ryo; Yoshizawa, Shin; Umemura, Shin-ichiro

2013-08-01

112

Characterization of in vitro healthy and pathological human liver tissue periodicity using backscattered ultrasound signals.  

PubMed

This work studied the periodicity of in vitro healthy and pathologic liver tissue, using backscattered ultrasound (US) signals. It utilized the mean scatterer spacing (MSS) as a parameter of tissue characterization, estimated by three methods: the spectral autocorrelation (SAC), the singular spectrum analysis (SSA) and the quadratic transformation method (SIMON). The liver samples were classified in terms of tissue status using the METAVIR scoring system. Twenty tissue samples were classified in four groups: F0, F1, F3 and F4 (five samples for each). The Kolmogorov-Smirnov test (applied on group pairs) resulted as nonsignificant (p > 0.05) for two pairs only: F1/F3 (for SSA) and F3/F4 (for SAC). A discriminant analysis was applied using as parameters the MSS mean (MSS) and standard deviation (sigmaMSS), the estimates histogram mode (mMSS), and the speed of US (mc(foie)) in the medium, to evaluate the degree of discrimination among healthy and pathologic tissues. The better accuracy (Ac) with SAC (80%) was with parameter group (MSS, sigmaMSS, mc(foie)), achieving a sensitivity (Ss) of 92.3% and a specificity (Sp) of 57.1%. For SSA, the group with all four parameters showed an Ac of 75%, an Ss of 78.6% and an Sp of 66.70%. SIMON obtained the best Ac of all (85%) with group (MSS, mMSS, mc(foie)), an Ss of 100%, but with an Sp of 50%. PMID:16677924

Machado, Christiano Bittencourt; Pereira, Wagner Coelho de Albuquerque; Meziri, Mahmoud; Laugier, Pascal

2006-05-01

113

FUNDAMENTAL AREAS OF PHENOMENOLOGY (INCLUDING APPLICATIONS): Modeling of Nonlinear Propagation in Multi-layer Biological Tissues for Strong Focused Ultrasound  

NASA Astrophysics Data System (ADS)

A theoretical model of the nonlinear propagation in multi-layered tissues for strong focused ultrasound is proposed. In this model, the spheroidal beam equation (SBE) is utilized to describe the nonlinear sound propagation in each layer tissue, and generalized oblique incidence theory is used to deal with the sound transmission between two layer tissues. Computer simulation is performed on a fat-muscle-liver tissue model under the irradiation of a 1 MHz focused transducer with a large aperture angle of 35°. The results demonstrate that the tissue layer would change the amplitude of sound pressure at the focal region and cause the increase of side petals.

Fan, Ting-Bo; Liu, Zhen-Bo; Zhang, Zhe; Zhang, Dong; Gong, Xiu-Fen

2009-08-01

114

Error in estimates of tissue material properties from shear wave dispersion ultrasound vibrometry.  

PubMed

Shear wave velocity measurements are used in elasticity imaging to find the shear elasticity and viscosity of tissue. A technique called shear wave dispersion ultrasound vibrometry (SDUV) has been introduced to use the dispersive nature of shear wave velocity to locally estimate the material properties of tissue. Shear waves are created using a multifrequency ultrasound radiation force, and the propagating shear waves are measured a few millimeters away from the excitation point. The shear wave velocity is measured using a repetitive pulse-echo method and Kalman filtering to find the phase of the harmonic shear wave at 2 different locations. A viscoelastic Voigt model and the shear wave velocity measurements at different frequencies are used to find the shear elasticity (mu(1)) and viscosity (mu(2)) of the tissue. The purpose of this paper is to report the accuracy of the SDUV method over a range of different values of mu(1) and mu(2). A motion detection model of a vibrating scattering medium was used to analyze measurement errors of vibration phase in a scattering medium. To assess the accuracy of the SDUV method, we modeled the effects of phase errors on estimates of shear wave velocity and material properties while varying parameters such as shear stiffness and viscosity, shear wave amplitude, the distance between shear wave measurements (delta r), signal-to-noise ratio (SNR) of the ultrasound pulse-echo method, and the frequency range of the measurements. We performed an experiment in a section of porcine muscle to evaluate variation of the aforementioned parameters on the estimated shear wave velocity and material property measurements and to validate the error prediction model. The model showed that errors in the shear wave velocity and material property estimates were minimized by maximizing shear wave amplitude, pulse-echo SNR, delta r, and the bandwidth used for shear wave measurements. The experimental model showed optimum performance could be obtained for delta r = 3 - 6 mm, SNR =35 dB, with a frequency range of 100 to 600 Hz, and with a shear wave amplitude on the order of a few microns down to 0.5 microm. The model provides a basis to explore different parameters related to implementation of the SDUV method. The experiment confirmed conclusions made by the model, and the results can be used for optimization of SDUV. PMID:19406703

Urban, Matthew W; Chen, Shigao; Greenleaf, James F

2009-04-01

115

In vivo tissue sampling of embryonic resorption sites using ultrasound guided biopsy.  

PubMed

In the polytocous European brown hare (Lepus europaeus) more than 23% of all successful implantations undergo embryonic resorption. The objective of the study was to establish a minimally invasive ultrasound guided biopsy technique to collect embryonic resorption tissue in vivo. The sampled material was genetically analysed to determine paternity and the sex of the embryo. Female hares were either mated or artificially inseminated and pregnancy was confirmed by ultrasound on day six post ovulation. Subsequent embryonic development was ultrasonographically monitored on a regular basis to detect embryos undergoing resorption. Cell material of the resorption site was collected under ultrasonographic control via transabdominal biopsy of the placenta or aspiration of resorption fluid. To avoid breathing movements during the biopsy, the animals were intubated and a short apnoea was evoked by assisted ventilation. The presence of embryonic cells in the biopsy material was confirmed by microsatellite analysis in 11 of the fluid samples (n = 28) and six of the placental samples (n = 8). The lower success rate in the fluid samples was attributed to the abundance of maternal cells which was confirmed by the analysis of fluid sample smears. Male sex of the embryos undergoing resorption was detected by SRY analysis for ten of the fluid samples and for one of the placental samples. The two biopsy techniques did not have any negative impact on the prenatal development of the healthy siblings nor did it influence the future breeding performance of the females that were biopsied. PMID:21601265

Schroeder, K; Drews, B; Roellig, K; Menzies, B R; Goeritz, F; Hildebrandt, T B

2011-05-23

116

Imaging monitored loosening of dense fibrous tissues using high-intensity pulsed ultrasound  

NASA Astrophysics Data System (ADS)

Pulsed high-intensity focused ultrasound (HIFU) is proposed as a new alternative treatment for contracture of dense fibrous tissue. It is hypothesized that the pulsed-HIFU can release the contracted tissues by attenuating tensile stiffness along the fiber axis, and that the stiffness reduction can be quantitatively monitored by change of B-mode images. Fresh porcine tendons and ligaments were adapted to an ex vivo model and insonated with pulsed-HIFU for durations ranging from 5 to 30 min. The pulse length was 91 µs with a repetition frequency of 500 Hz, and the peak rarefactional pressure was 6.36 MPa. The corresponding average intensities were kept around 1606 W cm-2 for ISPPA and 72.3 W cm-2 for ISPTA. B-mode images of the tissues were acquired before and after pulsed-HIFU exposure, and the changes in speckle intensity and organization were analyzed. The tensile stiffness of the HIFU-exposed tissues along the longitudinal axis was examined using a stretching machine. Histology examinations were performed by optical and transmission electron microscopy. Pulsed-HIFU exposure significantly decreased the tensile stiffness of the ligaments and tendons. The intensity and organization of tissue speckles in the exposed region were also decreased. The speckle changes correlated well with the degree of stiffness alteration. Histology examinations revealed that pulsed-HIFU exposure probably damages tissues via a cavitation-mediated mechanism. Our results suggest that pulsed-HIFU with a low duty factor is a promising tool for developing new treatment strategies for orthopedic disorders.

Yeh, Chia-Lun; Li, Pai-Chi; Shih, Wen-Pin; Huang, Pei-Shin; Kuo, Po-Ling

2013-10-01

117

Fetal Ultrasound  

MedlinePLUS

... this type of fetal ultrasound, a wand-like transducer is placed in your vagina to send out ... transabdominal fetal ultrasound is done by moving a transducer — a small plastic device that sends and receives ...

118

Ultrasound for noninvasive control of laser-induced tissue heating and coagulation  

NASA Astrophysics Data System (ADS)

The application of lasers to achieve localized thermal tissue damage is a common technique in minimally invasive surgery. Currently, there is no control during these treatments. In glaucoma therapy the laser energy applied and the beam direction are estimated prior to treatment, according to clinical experience and anatomic norm values. This lack of on-line control may limit success and lead to side effects. Precision and efficiency of treatment could be improved markedly by analysis of spatially resolved, temperature-dependent data obtained by Ultrasound Reflectometry. Thermally induced changes, as well as their localization were detected qualitatively in B-scan. Quantification was achieved by integration of high frequency RF-signals with the following resolution: spatial 50 micrometers , temporal 200 microsecond(s) , temperature 0.5 degree(s). The presented method is suitable for a non-invasive on-line therapy control.

Kleffner, Bernhard; Kriegerowski, Martin; Oltrup, Theo; Bende, Thomas; Jean, Benedikt J.

1996-05-01

119

Development and characterization of a tissue-mimicking material for high-intensity focused ultrasound.  

PubMed

A tissue-mimicking material (TMM) for the acoustic and thermal characterization of high-intensity focused ultrasound (HIFU) devices has been developed. The material is a high-temperature hydrogel matrix (gellan gum) combined with different sizes of aluminum oxide particles and other chemicals. The ultrasonic properties (attenuation coefficient, speed of sound, acoustical impedance, and the thermal conductivity and diffusivity) were characterized as a function of temperature from 20 to 70°C. The backscatter coefficient and nonlinearity parameter B/A were measured at room temperature. Importantly, the attenuation coefficient has essentially linear frequency dependence, as is the case for most mammalian tissues at 37°C. The mean value is 0.64f(0.95) dB·cm(-1) at 20°C, based on measurements from 2 to 8 MHz. Most of the other relevant physical parameters are also close to the reported values, although backscatter signals are low compared with typical human soft tissues. Repeatable and consistent temperature elevations of 40°C were produced under 20-s HIFU exposures in the TMM. This TMM is appropriate for developing standardized dosimetry techniques, validating numerical models, and determining the safety and efficacy of HIFU devices. PMID:21768024

King, Randy L; Liu, Yunbo; Maruvada, Subha; Herman, Bruce A; Wear, Keith A; Harris, Gerald R

2011-07-01

120

Ultrasound characterization of red blood cell aggregation with intervening attenuating tissue-mimicking phantoms  

PubMed Central

The analysis of the ultrasonic frequency-dependent backscatter coefficient of aggregating red blood cells reveals information about blood structural properties. The difficulty in applying this technique in vivo is due to the frequency-dependent attenuation caused by intervening tissue layers that distorts the spectral content of signals backscattered by blood. An optimization method is proposed to simultaneously estimate tissue attenuation and blood structure properties, and was termed the structure factor size and attenuation estimator (SFSAE). An ultrasound scanner equipped with a wide-band 25 MHz probe was used to insonify porcine blood sheared in both Couette and tubular flow devices. Since skin is one of the most attenuating tissue layers during in vivo scanning, four skin-mimicking phantoms with different attenuation coefficients were introduced between the transducer and the blood flow. The SFSAE gave estimates with relative errors below 25% for attenuations between 0.115 and 0.411 dB?MHz and kR<2.08 (k being the wave number and R the aggregate radius). The SFSAE can be useful to examine in vivo and in situ abnormal blood conditions suspected to promote pathophysiological cardiovascular consequences.

Franceschini, Emilie; Yu, Francois T.H.; Destrempes, Francois; Cloutier, Guy

2010-01-01

121

No effect of bipolar interferential electrotherapy and pulsed ultrasound for soft tissue shoulder disorders: a randomised controlled trial  

Microsoft Academic Search

OBJECTIVETo assess the efficacy of bipolar interferential electrotherapy (ET) and pulsed ultrasound (US) as adjuvants to exercise therapy for soft tissue shoulder disorders (SD).METHODSRandomised placebo controlled trial with a two by two factorial design plus an additional control group in 17 primary care physiotherapy practices in the south of the Netherlands. Patients with shoulder pain and\\/or restricted shoulder mobility, because

Geert J M G van der Heijden; Pieter Leffers; Pieter J M C Wolters; José J D Verheijden; Henk van Mameren; Jo P Houben; Lex M Bouter; Paul G Knipschild

1999-01-01

122

Non-invasive assessment of negative pressure wound therapy using high frequency diagnostic ultrasound: oedema reduction and new tissue accumulation.  

PubMed

Tissue oedema plays an important role in the pathology of chronic and traumatic wounds. Negative pressure wound therapy (NPWT) is thought to contribute to active oedema reduction, yet few studies have showed this effect. In this study, high frequency diagnostic ultrasound at 20 MHz with an axial resolution of 60 µm was used to assess the effect of NPWT at - 80 mmHg on pressure ulcers and the surrounding tissue. Wounds were monitored in four patients over a 3-month period during which changes in oedema and wound bed thickness (granulation tissue) were measured non-invasively. The results showed a rapid reduction of periwound tissue oedema in all patients with levels falling by a mean of 43% after 4 days of therapy. A 20% increase in the thickness of the wound bed was observed after 7 days due to new granulation tissue formation. Ultrasound scans through the in situ gauze NPWT filler also revealed the existence of macrodeformation in the tissue produced by the negative pressure. These preliminary studies suggest that non-invasive assessment using high frequency diagnostic ultrasound could be a valuable tool in clinical studies of NPWT. PMID:22672782

Young, Stephen R; Hampton, Sylvie; Martin, Robin

2012-06-04

123

Therapy planning and monitoring of tissue ablation by high intensity focused ultrasound (HIFU) using imaging and simulation.  

PubMed

High intensity focused ultrasound (HIFU) 'cooks' or ablates the target tissue at the focus of the ultrasound beam by thermal and cavitation effects. The HIFU is emerging as a non-invasive method for tumor ablation. The HIFU application for tissue ablation requires tools for dosimetry therapy planning, and real-time feedback of the intended and actual target tissues. Pretreatment planning is an important step for a successful HIFU therapy outcome. Typically, the therapy planning approach involves the use of pretreatment imaging data, defining the target and surrounding tissues by manual or semiautomatic segmentation, development of a 3-D anatomy model of the region of interest from segmentation or registration with a reference dataset, simulation of the HIFU beam and thermal dosimetry around the target tissue, display and 3-D visualization of imaging and simulation data, and review of the treatment plan options. Recent developments in therapy planning using imaging are targeted for specific applications such as prostate cancer using 3-D ultrasound images and uterine fibroids using MRI. However, significant developments have been accomplished in image guidance and feedback during the delivery of HIFU treatments. This talk reviews recent work towards therapy planning and presents approaches for developing strategies for HIFU therapy. It describes general and target-specific techniques and software tools for HIFU treatment planning using pretherapy imaging, and monitoring and controlling the HIFU delivery and tissue lesion using 1D, 2D and 3D ultrasound imaging. This aids development of optimized, high-precision HIFU applications for a controlled ablation of the target tumor. It also potentially reduces the overall treatment duration and exposure to non-target tissues. PMID:19163707

Amin, Viren; Wu, Liangshou; Long, Tao; Roberts, Ron; McClure, Scott; Ryken, Timothy

2008-01-01

124

Early detection of breast cancer: benefits and risks of supplemental breast ultrasound in asymptomatic women with mammographically dense breast tissue. A systematic review  

PubMed Central

Background Mammographic screening alone will miss a certain fraction of malignancies, as evidenced by retrospective reviews of mammograms following a subsequent screening. Mammographic breast density is a marker for increased breast cancer risk and is associated with a higher risk of interval breast cancer, i.e. cancer detected between screening tests. The purpose of this review is to estimate risks and benefits of supplemental breast ultrasound in women with negative mammographic screening with dense breast tissue. Methods A systematic search and review of studies involving mammography and breast ultrasound for screening of breast cancer was conducted. The search was performed for the period 1/2000-8/2008 within the data source of PubMed, DARE, and Cochrane databases. Inclusion and exclusion criteria were determined prospectively, and the Oxford evidence classification system for diagnostic studies was used for evidence level. The parameters biopsy rate, positive predictive value (PPV) for biopsy, cancer yield for breast ultrasound alone, and carcinoma detection rate by breast density were extracted or constructed. Results The systematic search identified no randomized controlled trials or systematic reviews, six cohort studies of intermediate level of evidence (3b) were found. Only two of the studies included adequate follow-up of subjects with negative or benign findings. Supplemental breast ultrasound after negative mammographic screening permitted diagnosis of primarily invasive carcinomas in 0.32% of women in breast density type categories 2-4 of the American College of Radiology (ACR); mean tumor size for those identified was 9.9 mm, 90% with negative lymph node status. Most detected cancers occurred in mammographically dense breast ACR types 3 and 4. Biopsy rates were in the range 2.3%-4.7%, with PPV of 8.4-13.7% for those biopsied due to positive ultrasound, or about one third of the PPV of biopsies due to mammography. Limitations: The study populations included wide age ranges, and the application to women age 50-69 years as proposed for mammographic screening could result in less striking benefit. Further validation studies should employ a uniform assessment system such as BI-RADS and report not only PPV, but also negative predictive value, sensitivity and specificity. Conclusion Supplemental breast ultrasound in the population of women with mammographically dense breast tissue (ACR 3 and 4) permits detection of small, otherwise occult, breast cancers. Potential adverse impacts for women in this intermediate risk group are associated with an increased biopsy rate.

2009-01-01

125

Tissue ablation in benign prostatic hyperplasia with high-intensity focused ultrasound.  

PubMed

The safety and effectiveness of tissue ablation by coagulative necrosis with high-intensity focused ultrasound (HIFU) applied through a rectal probe to 36 patients with symptomatic benign prostatic hyperplasia (BPH) was investigated in a phase II clinical trial. Overall, HIFU treatment was well tolerated, the mean hospital stay being 1.1 days. Negative side effects were transient urinary retention in 32/36 patients, hematuria in 2 patients and hematospermia resolving after 3-4 weeks (n = 15). After 3 months the maximum flow rate/s (Qmax) increased from 9.0 +/- 3.9 to 14.4 +/- 7.0 ml/s, the median flow rate/s (QM90) from 4.9 +/- 2.4 to 7.6 +/- 4.17 ml/s; the postvoid residual volume decreased from 128 +/- 88 to 57 +/- 35 ml and the AUA symptom score from 25.5 +/- 5 to 13.2 +/- 4.4. In conclusion, it was shown that tissue ablation in patients with symptomatic BPH using HIFU is safe and dramatically reduces both obstructive and irritative symptoms and leads to a significant increase in uroflow and a decrease in postvoid residual volume. PMID:7685695

Madersbacher, S; Kratzik, C; Szabo, N; Susani, M; Vingers, L; Marberger, M

1993-01-01

126

Spectral hole burning for ultrasound-modulated optical tomography of thick tissue.  

PubMed

We apply spectral hole burning (SHB)-aided detection in ultrasound-modulated optical tomography (UOT) to image optical heterogeneities in thick tissue-mimicking phantom samples and chicken breast tissue. The efficiency of SHB is improved by using a Tm(3+):YAG crystal of higher doping concentration (2.0-atomic%) and a double-pass pumping configuration, in which the pump beam is transmitted through the crystal twice to burn a deeper spectral hole with the available optical intensity. With the improved SHB-UOT system, we image absorbing, scattering, and phase objects that are embedded in the middle plane of a 30-mm-thick phantom sample. The imaging resolution was 0.5 mm in the lateral direction, as defined by the focal width of the ultrasonic transducer, and 1.5 mm in the axial direction, as determined by the ultrasonic burst length. We also image two absorbing objects embedded in a 32-mm-thick chicken breast sample. The results suggest that the improved SHB-UOT system is one step closer to the practical optical imaging application in biological and clinical studies. PMID:21198192

Xu, Xiao; Kothapalli, Sri-Rajasekhar; Liu, Honglin; Wang, Lihong V

127

Real-time 2D Imaging of Thermal and Mechanical Tissue Response to Focused Ultrasound  

NASA Astrophysics Data System (ADS)

An integrated system capable of performing high frame-rate two-dimensional (2D) temperature imaging in realtime is has been developed. The system consists of a SonixRP ultrasound scanner and a custom built data processing unit connected with Gigabit Ethernet (GbE). The SonixRP scanner which serves as the frontend of the integrated system allows us to have flexibilities of controlling the beam sequence and accessing the radio frequency (RF) data in realtime through its research interface. The RF data is then streamlined to the backend of the system through GbE, where the data is processed using a 2D temperature estimation algorithm running in a general purpose graphics processing unit (GPU). Using this system, we have developed a 2D high frame-rate imaging mode, M2D, for imaging the mechanical and thermal tissue response to subtherapeutic HIFU beams. In this paper, we present results from imaging subtherapetic HIFU beams in vitro porcine heart before and after lesion formation. The results demonstrate the feasibility of tissue parameter changes due to HIFU-induced lesions.

Liu, Dalong; Ebbini, Emad S.

2010-03-01

128

Comparative study of temperature measurements in ex vivo swine muscle and a tissue-mimicking material during high intensity focused ultrasound exposures.  

PubMed

Tissue-mimicking materials (TMMs) can provide a convenient, stable, and reproducible means for testing high intensity focused ultrasound (HIFU) devices. When TMMs containing thermal sensors are used to measure ultrasound-induced temperature rise, it is important that measurement results reasonably represent those that occur in biological tissue. Therefore the aim of this paper is to compare the thermal behavior of the TMM under HIFU exposure to that of ex vivo tissue. This was accomplished using both a previously developed TMM and fresh ex vivo swine muscle that were instrumented with bare 50 µm thin wire thermocouples. HIFU at 825 kHz was focused at the thermocouple junction. 30 s exposures of increasing peak negative pressure (1 to 5 MPa) were applied and the temperature profile during and after sonication was recorded. B-mode imaging was used to monitor bubble activity during sonication. If bubble formation was noted during the sonication, the sonication was repeated at the same pressure levels two more times at 20 min intervals. Temperature traces obtained at various pressure levels demonstrated similar types of heating profiles in both the tissue and TMM, the exact nature of which depended on whether bubbles formed during the HIFU exposure. The onset of bubble activity occurred at lower ultrasonic pressures in the TMM, but the basic temperature rise features due to HIFU exposure were essentially the same for both materials. PMID:22127191

Maruvada, S; Liu, Y; Pritchard, W F; Herman, B A; Harris, G R

2011-11-29

129

Full 2D displacement vector and strain tensor estimation for superficial tissue using beam-steered ultrasound imaging.  

PubMed

Ultrasound strain imaging is used to measure local tissue deformations. Usually, only strains along the ultrasound beam are estimated, because those estimates are most precise, due to the availability of phase information. For estimating strain in other directions we propose to steer the ultrasound beam at an angle, which allows estimating different projections of the 2D strain tensor, while phase information remains available. This study investigates beam steering at maximally three different angles to determine the full 2D strain tensor. The method was tested on simulated and experimental data of an inclusion phantom and a vessel phantom. The combination of data from a non-steered acquisition and acquisitions at a large positive and an equally large but negative steering angle enabled the most precise estimation of the strain components. The method outperforms conventional methods that do not use beam steering. PMID:20479516

Hansen, H H G; Lopata, R G P; Idzenga, T; de Korte, C L

2010-05-17

130

Ultrasound -Assisted Gene Transfer to Adipose Tissue-Derived Stem/Progenitor Cells (ASCs)  

NASA Astrophysics Data System (ADS)

In recent years, multilineage adipose tissue-derived stem cells (ASCs) have become increasingly attractive as a promising source for cell transplantation and regenerative medicine. Particular interest has been expressed in the potential to make tissue stem cells, such as ASCs and marrow stromal cells (MSCs), differentiate by gene transfection. Gene transfection using highly efficient viral vectors such as adeno- and sendai viruses have been developed for this purpose. Sonoporation, or ultrasound (US)-assisted gene transfer, is an alternative gene manipulation technique which employs the creation of a jet stream by ultrasonic microbubble cavitation. Sonoporation using non-viral vectors is expected to be a much safer, although less efficient, tool for prospective clinical gene therapy. In this report, we assessed the efficacy of the sonoporation technique for gene transfer to ASCs. We isolated and cultured adipocyets from mouse adipose tissue. ASCs that have the potential to differentiate with transformation into adipocytes or osteoblasts were obtained. Using the US-assisted system, plasmid DNA containing beta-galactosidase (beta-Gal) and green fluorescent protein (GFP) genes were transferred to the ASCs. For this purpose, a Sonopore 4000 (NEPAGENE Co.) and a Sonazoid (Daiichi Sankyo Co.) instrument were used in combination. ASCs were subjected to US (3.1 MHz, 50% duty cycle, burst rate 2.0 Hz, intensity 1.2 W/cm2, exposure time 30 sec). We observed that the gene was more efficiently transferred with increased concentrations of plasmid DNA (5-150 ?g/mL). However, further optimization of the US parameters is required, as the gene transfer efficiency was still relatively low. In conclusion, we herein demonstrate that a gene can be transferred to ASCs using our US-assisted system. In regenerative medicine, this system might resolve the current issues surrounding the use of viral vectors for gene transfer.

Miyamoto, Yoshitaka; Ueno, Hitomi; Hokari, Rei; Yuan, Wenji; Kuno, Shuichi; Kakimoto, Takashi; Enosawa, Shin; Negishi, Yoichi; Yoshinaka, Kiyoshi; Matsumoto, Yoichiro; Chiba, Toshio; Hayashi, Shuji

2011-09-01

131

Experiences Using a Special Purpose Robot for Focal Ultrasound Based Tissue Ablation  

NASA Astrophysics Data System (ADS)

This paper describes implementation, empirical set-up and ex vivo trial results of a non-invasive robotic surgery system, called FUSBOT-BS, to treat tumours/cancers by the use of High Intensity Focused Ultrasound (HIFU). The desired surgical effects of ultrasonic irradiation are decided by a pre-planned delivered dosage and the temporal aspects of wave propagation. The temperature rise in the target site depends upon the exposure conditions. A multiple transducer approach is adopted in this research. Surgical planning and deployment of the probes in a given location and specified trajectory is accomplished using robotic techniques. The test results for ablation were conducted in biological phantoms and in various animal tissues, in vitro, such as fat, muscle, and kidney from lamb, beef and pork. The representative results obtained in these empirical studies are presented, which help to understand dependence of crucial HIFU parameters to decide the treatment planning and surgical protocols. The robotic system achieved an end-point accuracy of +/-0.5mm. It is possible to precisely position target lesions and ablate remote target sites of varying shapes and sizes with flexible protocols.

Chauhan, S.; Li, J. R.; Mishral, R.; Lim, W. K.; Hacker, A.; Michel, M. S.; Alken, P.; Köhrmann, K. U.

2005-03-01

132

Ultrasound myocardial tissue characterization by integrated backscatter in children treated with anthracyclines.  

PubMed

The objective of our study was to evaluate integrated backscatter (IBS) measurement, an ultrasound method of myocardial tissue characterization, in children receiving cardiotoxic anthracyclines for malignancy. Myocardial injury is known to diminish the normal cyclic variation of IBS (CVIBS) during the cardiac cycle. We used a cross-sectional, case-controlled study of children receiving anthracyclines and serial, prospective observation in a subgroup of children. The study took place in a university-affiliated, tertiary referral center for pediatric cardiology and oncology. Children undergoing routine echocardiograms before, during, and after anthracycline treatment participated in this study. Children evaluated in the cardiology clinic for innocent murmurs participated as controls. There was no intervention. CVIBS was measured using specialized echocardiographic software which quantitates the intensity of backscattered echoes returning from myocardial cells within a user-defined region of interest. Standard echocardiographic measures of left ventricular function were also made. The results indicated that abnormal CVIBS was prevalent during anthracycline treatment (17%) and at late follow-up (20%). In serial studies, CVIBS decreased in all children after anthracycline treatment. Anthracycline dose and time since last dose did not predict which children would have abnormalities of left ventricular function or of CVIBS. This report provides preliminary evidence that CVIBS may be a useful supplement to the noninvasive, echocardiographic assessment of the heart during anthracycline treatment in children. PMID:10368451

Goens, M B; Karr, S S; Seibel, N; Martin, G R

133

Ultrasound dynamic micro-elastography applied to the viscoelastic characterization of soft tissues and arterial walls.  

PubMed

Quantitative noninvasive methods that provide in vivo assessment of mechanical characterization of living tissues, organs and artery walls are of interest because information on their viscoelastic properties in the presence of disease can affect diagnosis and treatment options. This article proposes the dynamic micro-elastography (DME) method to characterize viscoelasticity of small homogeneous soft tissues, as well as the adaptation of the method for vascular applications [vascular dynamic micro-elastography (VDME)]. The technique is based on the generation of relatively high-frequency (240-1100 Hz) monochromatic or transient plane shear waves within the medium and the tracking of these waves from radio-frequency (RF) echoes acquired at 25 MHz with an ultrasound biomicroscope (Vevo 770, Visualsonics). By employing a dedicated shear wave gated strategy during signal acquisition, postprocessed RF sequences could achieve a very high frame rate (16,000 images per s). The proposed technique successfully reconstructed shear wave displacement maps at very high axial (60 mum) and lateral (250 mum) spatial resolutions for motions as low as a few mum. An inverse problem formulated as a least-square minimization, involving analytical simulations (for homogenous and vascular geometries) and experimental measurements were performed to retrieve storage (G') and loss (G'') moduli as a function of the shearing frequency. Viscoelasticity measurements of agar-gelatin materials and of a small rat liver were proven feasible. Results on a very thin wall (3 mm thickness) mimicking artery enabled to validate the feasibility and the reliability of the vascular inverse problem formulation. Subsequently, the G' and G'' of a porcine aorta showed that both parameters are strongly dependent on frequency, suggesting that the vascular wall is mechanically governed by complex viscoelastic laws. PMID:20800176

Schmitt, Cédric; Hadj Henni, Anis; Cloutier, Guy

2010-09-01

134

Delivery of Colloidal Particles and Red Blood Cells to Tissue Through Microvessel Ruptures Created by Targeted Microbubble Destruction With Ultrasound  

Microsoft Academic Search

Background—We have previously shown that the application of ultrasound to thin-shelled microbubbles flowing through small microvessels (,7 mm in diameter) produces vessel wall ruptures in vivo. Because many intravascular drug- and gene-delivery vehicles are limited by the endothelial barrier, we hypothesized that this phenomenon could be used to deliver drug-bearing vehicles to tissue. Methods and Results—An exteriorized rat spinotrapezius muscle

Richard J. Price; Danny M. Skyba; Sanjiv Kaul; Thomas C. Skalak

2010-01-01

135

A model for the propagation and scattering of ultrasound in tissue  

Microsoft Academic Search

An inhomogeneous wave equation is derived describing propagation and scattering of ultrasound in an inhomogeneous medium. The scattering term is a function of density and propagation velocity perturbations. The integral solution to the wave equation is combined with a general description of the field from typical transducers used in clinical ultrasound to yield a model for the received pulse-echo pressure

1991-01-01

136

Noninvasive surgery of prostate tissue by high-intensity focused ultrasound: an updated report  

Microsoft Academic Search

High Intensity Focused Ultrasound (HIFU) has been clinically used for the treatment of benign prostatic hyperplasia (BPH) and it is experimentally applied for the treatment of localized prostate caner (PC). Recent advances in the transducer material and technology have permitted to combine the ultrasound visualization capability and HIFU on the same ceramic crystal. Also, the transducer efficiency has increased to

Narendra T. Sanghvi; J. Syrus; Richard S. Foster; Richard Bihrle; Richard W. Casey; Toyoak Uchida

2000-01-01

137

Noninvasive surgery of prostate tissue by high intensity focused ultrasound: an updated report  

Microsoft Academic Search

Objective: To establish clinical efficacy and safety of High Intensity Focused Ultrasound (HIFU) for the treatment of benign prostatic hyperplasia (BPH) in a multiple site clinical study. Methods: Seven clinical sites were set up for the studies, five in the USA, one in Canada and one in Japan respectively. Sixty two patients were enrolled in these three studies. Transrectal ultrasound

N. T Sanghvi; R. S Foster; R Bihrle; R Casey; T Uchida; M. H Phillips; J Syrus; A. V Zaitsev; K. W Marich; F. J Fry

1999-01-01

138

Microstructural change of potato tissues frozen by ultrasound-assisted immersion freezing  

Microsoft Academic Search

Power ultrasound has proved to be very useful in controlling crystallisation processes since sonication can enhance both the nucleation rate and crystal growth rate by producing fresh and\\/or more nucleation sites. Therefore, in this study, power ultrasound was applied to assist the freezing process. The results showed that the freezing rate of potato sample was improved with the application of

Da-Wen Sun; Bing Li

2003-01-01

139

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

PubMed Central

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.

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

2012-01-01

140

Magnetic resonance guided focused ultrasound surgery of uterine fibroids—The tissue effects of GnRH agonist pre-treatment  

Microsoft Academic Search

ObjectiveThe purpose of this study was to determine the ablative effect of magnetic resonance guided focused ultrasound (MRgFUS) on fibroid tissue following the administration of gonadotrophin releasing hormone (GnRH) agonist.

O. C. Smart; J. T. Hindley; L. Regana; W. M. W. Gedroyc

2006-01-01

141

Partial shrinkage of venous tissues near valves using High Intensity Focused Ultrasound  

NASA Astrophysics Data System (ADS)

The cross-section of a vein can be reduced by exposing the collagen of the vein wall to high temperature (85° C) for a few seconds. Partial shrinkage of the vein is appropriate for correcting deformations of valvular tissues that can cause the abnormal blood reflux which is the main cause of varicose veins and Superficial Venous Insufficiency. Due to its suitability for inducing localized heating, High Intensity Focused Ultrasound (HIFU) is a good method for correcting valvular tissue. In the present study, the feasibility of using HIFU for inducing partial shrinkage of the saphenous vein wall is demonstrated. The position and size of valvular deformations are well suited to being heated and, consequently, reduced with HIFU. The resulting shrinkage of deformations should restore normal function of the valve. An experimental protocol was used in which several in vitro segments of human saphenous vein were exposed with a monochromatic signal produced by a real-time imaging HIFU probe. The probe has a focal length of 45 mm, a diameter of 52.5 mm and operates at 3 MHz. Ultrasonic imaging, obtained with an 8-MHz 128-element linear array placed at the centre of the HIFU probe, was used to target the vein. The segment was inserted in a porcine muscle sample, and both were placed into a PVC cylinder. Individual sonications of the vein wall were performed for acoustic power values ranging between 8.75 and 35 W at a constant sonication duration of 5 s. Different durations ranging between 3 and 7 s at constant power were also tested. Finally, a long duration of 18 s was tested while the focal point was displaced along the vein wall at a speed of 0.5 mm/s. Results showed that shrinkage of the vein wall was observed using echographic and macroscopic analysis. In particular, the vein diameter was reduced by 15% for a sonication-duration of 18 s with continuous displacement of the focal point. Results showed that HIFU is suitable for partial shrinkage of the saphenous vein and suggest that correction of dysfunctional valvular tissue is feasible.

Pichardo, Samuel; Curiel, Laura; Milleret, René; Pichot, Olivier; Lacoste, François; Chapelon, Jean-Yves

2005-03-01

142

[Pharmacokinetics of radiotracers in the ocular tissues exposed to infrasound and ultrasound phonophoreses].  

PubMed

The paper compares the efficiency of infrasound and ultrasound phonophoreses. The efficiency was evaluated on the basis of the rate of radiotracers within the eye after infrasound or ultrasound exposure of the eyeball. The exposure was made after preliminary putting the radiotracer-impregnated application into the bulbar conjunctiva of an animal. Radioactivity was recorded on a Siemens gamma camera in its lifetime. The time course of changes in the radioactivities measured 10, 30, and 60 minutes after termination of exposures strongly suggests its stable increase in the eye exposed to infrasound. At the same time 10 minutes after ultrasound exposure, the increased concentration of a radiotracer in the eye was less than that after infrasound exposure and then it progressively decreased. Thus, having a significant phoretic activity, infrasound, as ultrasound, creates more favorable conditions for long drug storage in the eye. PMID:16886741

143

A Tissue-Mimicking Ultrasound Test Object Using Droplet Vaporization to Create Point Targets  

PubMed Central

Ultrasound test objects containing reference point targets could be useful for evaluating ultrasound systems and phase aberration correction methods. Polyacrylamide gels containing albumin-stabilized droplets (3.6 µm mean diameter) of dodecafluoropentane (DDFP) are being developed for this purpose. Perturbation by ultrasound causes spontaneous vaporization of the superheated droplets to form gas bubbles, a process termed acoustic droplet vaporization (ADV). The resulting bubbles (20 to 160 µm diameter) are small compared with acoustic wavelengths in diagnostic ultrasound and are theoretically suitable for use as point targets (phase errors <20° for typical f-numbers). Bubbles distributed throughout the material are convenient for determining the point spread function in an imaging plane or volume. Cooling the gel causes condensation of the DDFP droplets, which may be useful for storage. Studying ADV in such viscoelastic media could provide insight into potential bioeffects from rapid bubble formation.

Carneal, Catherine M.; Kripfgans, Oliver D.; Krucker, Jochen; Carson, Paul L.; Fowlkes, J. Brian

2012-01-01

144

Visualization of multimodal polymer-shelled contrast agents using ultrasound contrast sequences: an experimental study in a tissue mimicking flow phantom  

PubMed Central

Background A multimodal polymer-shelled contrast agent (CA) with target specific potential was recently developed and tested for its acoustic properties in a single element transducer setup. Since the developed polymeric CA has different chemical composition than the commercially available CAs, there is an interest to study its acoustic response when using clinical ultrasound systems. The aim of this study was therefore to investigate the acoustic response by studying the visualization capability and shadowing effect of three polymer-shelled CAs when using optimized sequences for contrast imaging. Methods The acoustic response of three types of the multimodal CA was evaluated in a tissue mimicking flow phantom setup by measuring contrast to tissue ratio (CTR) and acoustic shadowing using five image sequences optimized for contrast imaging. The measurements were performed over a mechanical index (MI) range of 0.2-1.2 at three CA concentrations (106, 105, 104 microbubbles/ml). Results The CTR-values were found to vary with the applied contrast sequence, MI and CA. The highest CTR-values were obtained when a contrast sequence optimized for higher MI imaging was used. At a CA concentration of 106 microbubbles/ml, acoustic shadowing was observed for all contrast sequences and CAs. Conclusions The CAs showed the potential to enhance ultrasound images generated by available contrast sequences. A CA concentration of 106 MBs/ml implies a non-linear relation between MB concentration and image intensity.

2013-01-01

145

Influence of ablated tissue on the formation of high-intensity focused ultrasound lesions  

Microsoft Academic Search

In order to ablate tumours using high-intensity focused ultrasound (HIFU) it is necessary to irradiate the tumour with a confluent array of single ultrasound exposures. We have identified a phenomenon that we term lesion-to-lesion interaction, which occurs when the spatial separation of individual exposures is such that an existing lesion appears to affect the formation of a subsequent lesion. This

Lili Chen; Gail ter Haar; Christopher R. Hill

1997-01-01

146

Monitoring tissue inflammation and responses to drug treatments in early stages of mice bone fracture using 50 MHz ultrasound.  

PubMed

Bone fracture induces moderate inflammatory responses that are regulated by cyclooxygenase-2 (COX-2) or 5-lipoxygenase (5-LO) for initiating tissue repair and bone formation. Only a handful of non-invasive techniques focus on monitoring acute inflammation of injured bone currently exists. In the current study, we monitored in vivo inflammation levels during the initial 2 weeks of the inflammatory stage after mouse bone fracture utilizing 50 MHz ultrasound. The acquired ultrasonic images were correlated well with histological examinations. After the bone fracture in the tibia, dynamic changes in the soft tissue at the medial-posterior compartment near the fracture site were monitored by ultrasound on the days of 0, 2, 4, 7, and 14. The corresponding echogenicity increased on the 2nd, 4th, and 7th day, and subsequently declined to basal levels after the 14th day. An increase of cell death was identified by the positive staining of deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) assay and was consistent with ultrasound measurements. The increases of both COX-2 and Leukotriene B4 receptor 1 (BLT1, 5-LO-relative receptor), which are regulators for tissue inflammation, in the immunohistochemistry staining revealed their involvement in bone fracture injury. Monitoring the inflammatory response to various non-steroidal anti-inflammatory drugs (NSAIDs) treatments was investigated by treating injured mice with a daily oral intake of aspirin (Asp), indomethacin (IND), and a selective COX-2 inhibitor (SC-236). The Asp treatment significantly reduced fracture-increased echogenicity (hyperechogenicity, p<0.05) in ultrasound images as well as inhibited cell death, and expression of COX-2 and BLT1. In contrast, treatment with IND or SC-236 did not reduce the hyperechogenicity, as confirmed by cell death (TUNEL) and expression levels of COX-2 or BLT1. Taken together, the current study reports the feasibility of a non-invasive ultrasound method capable of monitoring post-fracture tissue inflammation that positively correlates with histological findings. Results of this study also suggest that this approach may be further applied to elucidate the underlying mechanisms of inflammatory processes and to develop therapeutic strategies for facilitating fracture healing. PMID:23871514

Chen, Yen-Chu; Lin, Yi-Hsun; Wang, Shyh-Hau; Lin, Shih-Ping; Shung, K Kirk; Wu, Chia-Ching

2013-07-11

147

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

PubMed

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 experiments showed a reproducible pattern of the HMI displacement changes with a temperature at a slope equal to 0.8+/-0.11 and -0.79+/-0.14 microm degrees C(-1), prior to and after lesion formation in seven bovine liver samples, respectively. This technique was thus capable of following the protein-denatured lesion formation based on the variation of the HMI displacements. This method could, therefore, be applied for real-time monitoring of temperature-related stiffness changes of tissues during FUS, HIFU or other thermal therapies. PMID:18367802

Maleke, C; Konofagou, E E

2008-03-07

148

Ultrasound and Therapy  

NASA Astrophysics Data System (ADS)

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

Lafon, Cyril

149

The effects of magnetic resonance imaging-guided high-intensity focused ultrasound ablation on human cadaver breast tissue.  

PubMed

Magnetic Resonance Imaging-guided High-Intensity Focused Ultrasound (MR-HIFU) is a promising technique for non-invasive breast tumor ablation. The purpose of this study was to investigate the effects of HIFU ablation and thermal exposure on ex vivo human breast tissue. HIFU ablations were performed in three unembalmed cadaveric breast specimens using a clinical MR-HIFU system. Sonications were performed in fibroglandular and adipose tissue. During HIFU ablation, time-resolved anatomical MR images were acquired to monitor macroscopic tissue changes. Furthermore, the breast tissue temperature was measured using a thermocouple to investigate heating and cooling under HIFU exposure. After HIFU ablation, breast tissue samples were excised and prepared for histopathological analysis. In addition, thermal exposure experiments were performed to distinguish between different levels of thermal damage using immunohistochemical staining. Irreversible macroscopic deformations up to 3.7mm were observed upon HIFU ablation both in fibroglandular and in adipose tissue. No relationship was found between the sonication power or the maximum tissue temperature and the size of the deformations. Temperature measurements after HIFU ablation showed a slow decline in breast tissue temperature. Histopathological analysis of sonicated regions demonstrated ablated tissue and morphologically complete cell death. After thermal exposure, samples exposed to three different temperatures could readily be distinguished. In conclusion, the irreversible macroscopic tissue deformations in ex vivo human breast tissue observed during HIFU ablation suggest that it might be relevant to monitor tissue deformations during MR-HIFU treatments. Furthermore, the slow decrease in breast tissue temperature after HIFU ablation increases the risk of heat accumulation between successive sonications. Since cell death was inflicted after already 5minutes at 75°C, MR-HIFU may find a place in non-invasive treatment of breast tumors. PMID:23583321

Merckel, Laura G; Deckers, Roel; Baron, Paul; Bleys, Ronald L A W; van Diest, Paul J; Moonen, Chrit T W; Mali, Willem P Th M; van den Bosch, Maurice A A J; Bartels, Lambertus W

2013-04-09

150

Real-Time Tissue Change Monitoring on the Sonablate® 500 during High Intensity Focused Ultrasound (HIFU) Treatment of Prostate Cancer  

NASA Astrophysics Data System (ADS)

Sonablate® 500 (SB-500) HIFU devices have been successfully used to treat prostate cancer non-invasively. In addition, Visually Directed HIFU with the SB-500 has demonstrated higher efficacy. Visually Directed HIFU works by displaying hyperechoic changes on the B-mode ultrasound images. However, small changes in the grey-scale images are not detectable by Visually Directed HIFU. To detect all tissue changes reliably, the SB-500 was enhanced with quantitative, real-time Tissue Change Monitoring (TCM) software. TCM uses pulse-echo ultrasound backscattered RF signals in 2D to estimate changes in the tissue properties caused by HIFU. The RF signal energy difference is calculated in selected frequency bands (pre and post HIFU) for each treatment site. The results are overlaid on the real-time ultrasound image in green, yellow and orange to represent low, medium and high degree of change in backscattered energy levels. The color mapping scheme was derived on measured temperature and backscattered RF signals from in vitro chicken tissue experiments. The TCM software was installed and tested in a clinical device to obtain human RF data. Post HIFU contrast enhanced MRI scans verified necrotic regions of the prostate. The color mapping success rate at higher HIFU power levels was 94% in the initial clinical test. Based on these results, TCM software has been released for wider usage. The clinical studies with TCM in Japan and The Bahamas have provided the following PSA (ng/ml) results. Japan (n = 97), PSA pre-treatment/post-treatment minimum 0.7/0.0, maximum 76.0/4.73, median 6.89/0.07, standard deviation 11.19/0.62. The Bahamas (n = 59), minimum 0.4/0.0, maximum 13.0/1.4, median 4.7/0.1, standard deviation 2.8/0.3.

Chen, Wo-Hsing; Sanghvi, Narendra T.; Carlson, Roy; Uchida, Toyoaki

2011-09-01

151

The effect of 40 kHz ultrasound on tissue plasminogen activator-induced clot lysis in three in vitro models  

NASA Astrophysics Data System (ADS)

In previous work from the same laboratory, high-frequency ultrasound (US) (3 MHz) was shown to promote in vitro fibrinolysis through enhanced supply of plasminogen to the clot surface. The application of high-frequency US is limited in vivo due to tissue heating. Low-frequency US, however, has less tissue heating and improved penetration. Internal plasma clot lysis and external lysis with compacted and non-compacted plasma clots were used to determine the magnitude of the effect of low-frequency US (40 kHz; 0.5 W/cm2) on tissue plasminogen activator-induced lysis and to elucidate the mechanisms behind the effect. Ultrasound enhanced lysis in all three models, with the largest effects (4-fold) in the external lysis model with compacted plasminogen-poor clots. The acceleration effect of ultrasound in this model decreased with increasing t-PA-and decreasing plasminogen concentrations. Ultrasound had a much smaller effect in this model when compacted plasminogen-rich clots were used. In the external lysis, non-compacted clot model, ultrasound resulted in consistently higher lysis rates. The acceleration effect of lysis, increased slightly (1.3 to 1.8-fold) with increasing t-PA-and decreasing plasminogen concentrations. Plasminogen supply to the clot surface was again shown to be an important contributor to ultrasound-enhanced lysis. [M. Pieters, R. T. Hekkenberg, M. Barrett-Bergshoeff, and D. C. Rijken. Ultrasound in Med & Biol 30, 1545-1552 (2004).

Pieters, Marlien; Hekkenberg, Rob T.; Barrett-Bergshoeff, Marrie; Rijken, Dingeman C.

2005-04-01

152

Quantitative Imaging of Young's Modulus of Soft Tissues from Ultrasound Water Jet Indentation: A Finite Element Study  

PubMed Central

Indentation testing is a widely used approach to evaluate mechanical characteristics of soft tissues quantitatively. Young's modulus of soft tissue can be calculated from the force-deformation data with known tissue thickness and Poisson's ratio using Hayes' equation. Our group previously developed a noncontact indentation system using a water jet as a soft indenter as well as the coupling medium for the propagation of high-frequency ultrasound. The novel system has shown its ability to detect the early degeneration of articular cartilage. However, there is still lack of a quantitative method to extract the intrinsic mechanical properties of soft tissue from water jet indentation. The purpose of this study is to investigate the relationship between the loading-unloading curves and the mechanical properties of soft tissues to provide an imaging technique of tissue mechanical properties. A 3D finite element model of water jet indentation was developed with consideration of finite deformation effect. An improved Hayes' equation has been derived by introducing a new scaling factor which is dependent on Poisson's ratios v, aspect ratio a/h (the radius of the indenter/the thickness of the test tissue), and deformation ratio d/h. With this model, the Young's modulus of soft tissue can be quantitatively evaluated and imaged with the error no more than 2%.

Lu, Min-Hua; Mao, Rui; Lu, Yin; Liu, Zheng; Wang, Tian-Fu; Chen, Si-Ping

2012-01-01

153

Ultrasound Transducer and System for Real-Time Simultaneous Therapy and Diagnosis for Noninvasive Surgery of Prostate Tissue  

PubMed Central

For noninvasive treatment of prostate tissue using high intensity focused ultrasound (HIFU), this paper proposes a design of an integrated multi-functional confocal phased array (IMCPA) and a strategy to perform both imaging and therapy simultaneously with this array. IMCPA is composed of triple-row phased arrays: a 6 MHz array in the center row for imaging and two 4 MHz arrays in the outer rows for therapy. Different types of piezoelectric materials and stack configurations may be employed to maximize their respective functionalities, i.e., therapy and imaging. Fabrication complexity of IMCPA may be reduced by assembling already constructed arrays. In IMCPA, reflected therapeutic signals may corrupt the quality of imaging signals received by the center row array. This problem can be overcome by implementing a coded excitation approach and/or a notch filter when B-mode images are formed during therapy. The 13-bit Barker code, which is a binary code with unique autocorrelation properties, is preferred for implementing coded excitation, although other codes may also be used. From both Field II simulation and experimental results, whether these remedial approaches would make it feasible to simultaneously carry out imaging and therapy by IMCPA was verifeid. The results showed that the 13-bit Barker code with 3 cycles per bit provided acceptable performances. The measured ?6 dB and ?20 dB range mainlobe widths were 0.52 mm and 0.91 mm, respectively, and a range sidelobe level was measured to be ?48 dB regardless of whether a notch filter was used. The 13-bit Barker code with 2 cycles per bit yielded ?6dB and ?20dB range mainlobe widths of 0.39 mm and 0.67 mm. Its range sidelobe level was found to be ?40 dB after notch filtering. These results indicate the feasibility of the proposed transducer design and system for real-time imaging during therapy.

Jeong, Jong Seob; Chang, Jin Ho; Shung, K. Kirk

2009-01-01

154

In-vivo mechanical property assessment of a biodegradable polyurethane tissue construct on rat abdominal repair model using ultrasound elasticity imaging  

Microsoft Academic Search

Non-invasively monitoring the mechanical property change of the engineered tissue constructs in vivo may help evaluate and feedback tissue scaffold design. In this paper, ultrasound elasticity imaging (UEI) was applied to detect mechanical property changes of the implanted polyurethane tissue constructs on a rat abdominal defect. Bi-axial mechanical measurements on the excised tissue\\/scaffold constructs were performed for comparison with the

S. Tripathy; K. Takanari; R. Hashizume; Y. Hong; N. J. Amoroso; K. L. Fujimoto; M. S. Sacks; W. R. Wagner; K. Kim

2010-01-01

155

Real-time interlaced ultrasound and photoacoustic system for in vivo ovarian tissue imaging  

NASA Astrophysics Data System (ADS)

In this paper, we report an ultrafast co-registered ultrasound and photoacoustic imaging system based on FPGA parallel processing. The system features 128-channel parallel acquisition and digitization, along with FPGA-based reconfigurable processing for real-time co-registered imaging of up to 15 frames per second that is only limited by the laser pulse repetition frequency of 15 Hz. We demonstrated the imaging capability of the system by live imaging of a mouse tumor model in vivo, and imaging of human ovaries ex vivo. A compact transvaginal probe that includes the PAT illumination using a fiber-optic assembly was used for this purpose. The system has the potential ability to assist a clinician to perform transvaginal ultrasound scanning and to localize the ovarian mass, while simultaneously mapping the light absorption of the ultrasound detected mass to reveal its vasculature using the co-registered PAT.

Alqasemi, Umar; Li, Hai; Yuan, Guangqian; Kumavor, Patrick; Zanganeh, Saeid; Zhu, Quing

2013-03-01

156

Comparison of ultrasound attenuation and backscatter estimates in layered tissue-mimicking phantoms among three clinical scanners.  

PubMed

Backscatter and attenuation coefficient estimates are needed in many quantitative ultrasound strategies. In clinical applications, these parameters may not be easily obtained because of variations in scattering by tissues overlying a region of interest (ROI). The goal of this study is to assess the accuracy of backscatter and attenuation estimates for regions distal to nonuniform layers of tissue-mimicking materials. In addition, this work compares results of these estimates for "layered" phantoms scanned using different clinical ultrasound machines. Two tissue-mimicking phantoms were constructed, each exhibiting depth-dependent variations in attenuation or backscatter. The phantoms were scanned with three ultrasound imaging systems, acquiring radio frequency echo data for offline analysis. The attenuation coefficient and the backscatter coefficient (BSC) for sections of the phantoms were estimated using the reference phantom method. Properties of each layer were also measured with laboratory techniques on test samples manufactured during the construction of the phantom. Estimates of the attenuation coefficient versus frequency slope, ?(0), using backscatter data from the different systems agreed to within 0.24 dB/cm-MHz. Bias in the ?(0) estimates varied with the location of the ROI. BSC estimates for phantom sections whose locations ranged from 0 to 7 cm from the transducer agreed among the different systems and with theoretical predictions, with a mean bias error of 1.01 dB over the used bandwidths. This study demonstrates that attenuation and BSCs can be accurately estimated in layered inhomogeneous media using pulse-echo data from clinical imaging systems. PMID:23160474

Nam, Kibo; Rosado-Mendez, Ivan M; Wirtzfeld, Lauren A; Ghoshal, Goutam; Pawlicki, Alexander D; Madsen, Ernest L; Lavarello, Roberto J; Oelze, Michael L; Zagzebski, James A; O'Brien, William D; Hall, Timothy J

2012-10-01

157

Shock-induced heating and millisecond boiling in gels and tissue due to high intensity focused ultrasound  

PubMed Central

Nonlinear propagation causes high intensity ultrasound waves to distort and generate higher harmonics, which are more readily absorbed and converted to heat than the fundamental frequency. Although such nonlinear effects have previously been investigated and found not to significantly alter high intensity focused ultrasound (HIFU) treatments, two results reported here change this paradigm. One is that at clinically relevant intensity levels, HIFU waves not only become distorted but form shock waves in tissue. The other is that the generated shock waves heat the tissue to boiling in much less time than predicted for undistorted or weakly distorted waves. In this study, a 2-MHz HIFU source operating at peak intensities up to 25,000 W/cm2 was used to heat transparent tissue-mimicking phantoms and ex vivo bovine liver samples. Initiation of boiling was detected using high-speed photography, a 20-MHz passive cavitation detector, and fluctuation of the drive voltage at the HIFU source. The time to boil obtained experimentally was used to quantify heating rates and was compared to calculations using weak shock theory and the shock amplitudes obtained from nonlinear modeling and from measurements with a fiber optic hydrophone. As observed experimentally and predicted by calculations, shocked focal waveforms produced boiling in as little as 3 ms and the time to initiate boiling was sensitive to small changes in HIFU output. Nonlinear heating due to shock waves is therefore important to HIFU and clinicians should be aware of the potential for very rapid boiling since it alters treatments.

Canney, Michael S.; Khokhlova, Vera A.; Bessonova, Olga V.; Bailey, Michael R.; Crum, Lawrence A.

2009-01-01

158

The activation of tissue factor by high intensity focused ultrasound-a pathway to acoustic-biochemical hemostasis  

NASA Astrophysics Data System (ADS)

High intensity focused ultrasound (HIFU) is believed to have great potential for inducing hemostasis in severely bleeding trauma victims. The addition of HIFU-activated biomolecular substances to the blood during treatment could significantly reduce the time required to achieve hemostasis, but such substances must remain inactive everywhere except at the site of injury. The integral-membrane protein, tissue factor (TF), is by far the most potent known trigger for the blood clotting cascade. We propose to employ liposomes with the extracellular domain of TF facing the lumen (``encrypted TF'') to allow the TF molecules to be introduced into the blood stream without causing systemic activation of coagulation. HIFU sonication at the site of injury will be used to break up the liposomes and thereby expose TF to the plasma, thus combining the hemostatic potential of HIFU along with an increase in the rate of clot formation triggered by TF. In our initial studies we have produced a range of concentrations of liposomes containing encrypted TF in a buffer solution and exposed them to ultrasound at a number of different intensity levels and duty cycles. Clotting assays were performed to determine the level of the desired effect of the ultrasound. The results suggest that HIFU can be effective in exposing active TF from the encrypted liposomes to accelerate blood clotting at the site of exposure.

Yang, Xinmai; Barber, Frank E.; Morrissey, James H.; Church, Charles C.

2006-05-01

159

Nondestructive Evaluation of Tissue Engineered Articular Cartilage Using Time-Resolved Fluorescence Spectroscopy and Ultrasound Backscatter Microscopy  

PubMed Central

The goal of this study is to evaluate the ability of a bimodal technique integrating time-resolved fluorescence spectroscopy (TRFS) and ultrasound backscatter microscopy (UBM) for nondestructive detection of changes in the biochemical, structural, and mechanical properties of self-assembled engineered articular cartilage constructs. The cartilage constructs were treated with three chemical agents (collagenase, chondroitinase-ABC, and ribose) to induce changes in biochemical content (collagen and glycosaminoglycan [GAG]) of matured constructs (4 weeks); and to subsequently alter the mechanical properties of the construct. The biochemical changes were evaluated using TRFS. The microstructure and the thickness of the engineered cartilage samples were characterized by UBM. The optical and ultrasound results were validated against those acquired via conventional techniques including collagen and GAG quantification and measurement of construct stiffness. Current results demonstrated that a set of optical parameters (e.g., average fluorescence lifetime and decay constants) showed significant correlation (p<0.05) with biochemical and mechanical data. The high-resolution ultrasound images provided complementary cross-section information of the cartilage samples morphology. Therefore, the technique was capable of nondestructively evaluating the composition of extracellular matrix and the microstructure of engineered tissue, demonstrating great potential as an alternative to traditional destructive assays.

Responte, Donald; Xie, Hongtao; Liu, Jing; Fatakdawala, Hussain; Hu, Jerry; Athanasiou, Kyriacos A.

2012-01-01

160

Histotripsy in focused ultrasound surgery: Mechanical ablation of tissue using controlled acoustic cavitation  

NASA Astrophysics Data System (ADS)

This research has investigated non-invasive tissue ablation techniques in ultrasonic surgery that are mediated primarily by the mechanical effects of controlled acoustic cavitation, thereby de-emphasizing the role of thermal coagulation during treatment of diseased tissues. This approach is referred to as "histotripsy," in which soft tissues are broken apart by mechanical agitation, in analogy to established lithotripsy procedures whereby renal stones are similarly comminuted. During histotripsy, cavitation microbubbles are formed endogenously in the treatment volume due to the intense rarefactional pressures (> 20 MPa) incurred. The actions of these microbubbles can impart severe yet highly localized mechanical damage to surrounding cellular architecture. The primary goal of this research was to investigate acoustic methods to control these powerful cavitation effects in order to produce therapeutic soft tissue lesions with minimal thermal invasiveness to surrounding collateral structures. Toward this end, an acoustic pulsing scheme was developed to actively sustain cavitation activity through the use of short-duration (e.g., 15 mus), high-intensity (e.g., 40 kW/cm2 ISPPA) pulses delivered at low repetition frequencies (e.g., 0.17 kHz). This approach maintained the microbubble population during treatment without producing significant temperature elevations (e.g., DeltaT = 5°C). Cavitation-mediated damage morphology in porcine myocardium and renal parenchyma consisted of well-circumscribed, 0.5-1 cm3 voids containing homogenized tissue slurry. Standard histological staining revealed extremely fine pulverization that often bisected single cells. This type of damage morphology offers particular advantages over thermal ablation in applications where diseased or impeding tissue must be physically removed, not merely treated and left in situ. In general, the ability to sustain effective cavitation during histotripsy was strongly influenced by acoustic pulse conditions, as measured by four specific metrics: (i) the prevalence of homogenate within the lesion; (ii) the Young's modulus following treatment; (iii) the degree of spatio-temporal variability in acoustic backscatter; (iv) the duration of light scattering from bubble surfaces inside the lesion, measured using fiber-optic techniques. Consistent trends were observed in the behavior of all four metrics as acoustic input conditions were adjusted, lending supportive evidence that the histotripsy process can be controlled through application of rationally-based pulsing strategies designed to manage resident microbubble activity.

Parsons, Jessica Erin

161

[How to make sure a balloon-type gastrostomy replacement was made right by ultrasound].  

PubMed

With the spread of gastric fistula, there have been increased reports of catheter aberrant and fistula damage during the time of catheter exchange procedures. Therefore, it has been recommended that a diagnostic imaging or endoscopic gastrostomy should be employed to make sure a catheter exchange was properly done. However, it is difficult to enforce an inspection using an X-ray or endoscopy in the home care environment. Here we examined the usefulness and problems associated with ultrasound catheter-validation for home care environment. Of 33 patients who received gastrostomy, we focused on 6 patients who had gastrostomy exchanged at home. Four out of 6 patients with a balloon-type gastrostomy exchanged clearly confirmed a good result by ultra sound. However, a patient with bumper-type was unclear. The reason being unclear was due to the material and shape of the appearance by the echo. Left costal arch operations approach is to scan the probe along the left side of the abdomen below the costal arch, so that a replaced gastrostomy catheter could be confirmed by following the low echoic area of the spleen, stomach vault and into the stomach cavity. It is considered that ultrasound examination of the exchanged balloon-type gastrostomy was useful under a consideration of patient's health conditions. PMID:22189316

Imai, Kazutaka; Hisajima, Kazuhiro; Suzuki, Jun; Soga, Yukihiro; Yasukawa, Keigo

2011-12-01

162

A Study of Bubble Activity Generated in Ex Vivo Tissue by High Intensity Focused Ultrasound  

Microsoft Academic Search

Cancer treatment by extracorporeal high-intensity focused ultrasound (HIFU) is constrained by the time required to ablate clinically relevant tumour volumes. Although cavitation may be used to optimize HIFU treatments, its role during lesion formation is ambiguous. Clear differentiation is required between acoustic cavitation (noninertial and inertial) effects and bubble formation arising from two thermally-driven effects (the vapourization of liquid into

James McLaughlan; Ian Rivens; Timothy Leighton; Gail ter Haar

2010-01-01

163

Ultrasound and hypersound generation of new-type solitons and bisolitons in crystals  

NASA Astrophysics Data System (ADS)

It has been shown that the principally new-type solitons and bisolitons are generated during the pulse impact of ultrasound and hypersound on crystal monatomic materials in addition to the known solitons. New-type bisolitons analogous to the bisolitons previously found by an analytical approach have been discovered with the use of the molecular dynamics method. It has been shown that the dispersion curve of these bisolitons is close to the dispersion curve of the conventional solitons. A subsonic compression soliton, the dispersion curve of which crosses the phonon dispersion curve, has been found along with the known supersonic compression soliton. The characteristics of the new-type solitons and bisolitons in uranium and plutonium crystal lattices are presented.

Dubovsky, O. A.; Orlov, A. V.

2012-12-01

164

Effect of ethanol injection on cavitation and heating of tissues exposed to high-intensity focused ultrasound.  

PubMed

Cavitation activity and temperature rise have been investigated in a tissue-mimicking material and excised bovine liver treated with ethanol and insonated with a 0.825 MHz focused acoustic transducer. The acoustic power was varied from 1.3 to 26.8 W to find the threshold leading to the onset of inertial cavitation. Cavitation events were quantified by three independent techniques: B-mode ultrasound imaging, needle hydrophone measurements and passive cavitation detection. Temperature in or near the focal zone was measured by thermocouples embedded in the samples. The results of this study indicate that the treatment of tissue phantoms and bovine liver samples with ethanol reduces their threshold power for inertial cavitation. This in turn leads to a sudden rise in temperature in ethanol-treated samples at a lower acoustic power than that in untreated ones. The analysis of passive cavitation detection data shows that once the threshold acoustic power is reached, inertial cavitation becomes a major contributor to acoustic scattering in ethanol-treated phantoms and bovine liver samples as compared to control. This study opens up the possibility of improved tumor ablation therapy via a combination of percutaneous ethanol injection and high-intensity focused ultrasound. PMID:22290554

Chen, C; Liu, Y; Maruvada, S; Myers, M; Khismatullin, D

2012-01-31

165

A new type of very low-power modulated laser: soft-tissue changes induced in osteoarthritic patients revealed by sonography.  

PubMed

Patients with symptomatic osteoarthritis of the cervical spine were studied by ultrasound examination. The region of interest was the soft connective tissue layer above the right and the left superior trapezium that revealed a significant difference in thickness between the left and right side. The aching side was treated with a new type of very low-power, modulated laser for 3 min. Immediately after application, the sonographic examination revealed a significant symmetrization of the subcutaneous tissue. PMID:11146897

Baratto, L; Capra, R; Farinelli, M; Monteforte, P; Morasso, P; Rovetta, G

2000-01-01

166

HCV-RNA detection in ultrasound-guided fine needle biopsies of liver nodules and surrounding tissue.  

PubMed

HCV-RNA was examined in serum and liver tissue obtained from 8 hepatitis B surface antigen (HBsAg) negative patients with liver nodules ranging in size from 2 to 11 cm. Histological examination of ultrasound-guided fine needle biopsies revealed the presence of hepatocellular carcinoma (HCC) in six patients (5 of whom were anti-HCV positive), cholangiocarcinoma in 1 patient (anti-HCV positive) and dysplastic regenerative nodule in 1 patient (anti-HCV negative). The HCCs were surrounded by cirrhosis (3 cases), chronic active hepatitis (CAH) (n = 2) and post hepatitic fibrosis (n = 1), the cholangiocarcinoma by CAH and the regenerative nodule by cirrhotic liver. Total and replicative intermediate HCV-RNA was analyzed by reverse-transcription-nested PCR of the 5'-untranslated region. The five patients with HCC had HCV-RNA in serum, in tumorous and surrounding liver tissues. The viral nucleic acid was also detected in the cirrhotic tissue surrounding the cholangiocarcinoma but not in the tumor. Two out of 5 HCC patients had replicative intermediate RNA (negative strand) in tumorous tissue, 4 in nontumorous tissue and 3 in serum. These results demonstrate that fine needle biopsy can provide sufficient material for both histological examination and HCV-RNA determination and suggest the existence of continuous viral replication during the carcinogenic process. PMID:7989430

Marin, M G; Cariani, E; Salmi, A; Rangoni, G; Chiodera, P; Pizzocolo, G; Albertini, A

1994-07-01

167

Experiences Using a Special Purpose Robot for Focal Ultrasound Based Tissue Ablation  

Microsoft Academic Search

This paper describes implementation, empirical set-up and ex vivo trial results of a non-invasive robotic surgery system, called FUSBOT-BS, to treat tumours\\/cancers by the use of High Intensity Focused Ultrasound (HIFU). The desired surgical effects of ultrasonic irradiation are decided by a pre-planned delivered dosage and the temporal aspects of wave propagation. The temperature rise in the target site depends

S. Chauhan; J. R. Li; R. Mishral; W. K. Lim; A. Hacker; M. S. Michel; P. Alken; K. U. Köhrmann

2005-01-01

168

Assessment of Shear Modulus of Tissue Using Ultrasound Radiation Force Acting on a Spherical Acoustic Inhomogeneity  

PubMed Central

An ultrasound-based method to locally assess the shear modulus of a medium is reported. The proposed approach is based on the application of an impulse acoustic radiation force to an inhomogeneity in the medium and subsequent monitoring of the spatio-temporal response. In our experimental studies, a short pulse produced by a 1.5-MHz highly focused ultrasound transducer was used to initiate the motion of a rigid sphere embedded into an elastic medium. Another 25 MHz focused ultrasound transducer operating in pulse-echo mode was used to track the displacement of the sphere. The experiments were performed in gel phantoms with varying shear modulus to demonstrate the relationship between the displacement of the sphere and shear modulus of the surrounding medium. Because the magnitude of acoustic force applied to sphere depends on the acoustic material properties and, therefore, cannot be used to assess the absolute value of shear modulus, the temporal behavior of the displacement of the sphere was analyzed. The results of this study indicate that there is a strong correlation between the shear modulus of a medium and spatio-temporal characteristics of the motion of the rigid sphere embedded in this medium.

Karpiouk, Andrei B.; Aglyamov, Salavat R.; Ilinskii, Yury A.; Zabolotskaya, Eugenia A.; Emelianov, Stanislav Y.

2011-01-01

169

High-frequency ultrasound for monitoring changes in liver tissue during preservation  

NASA Astrophysics Data System (ADS)

Currently the only method to assess liver preservation injury is based on liver appearance and donor medical history. Previous work has shown that high-frequency ultrasound could detect ischemic cell death due to changes in cell morphology. In this study, we use high-frequency ultrasound integrated backscatter to assess liver damage in experimental models of liver ischemia. Ultimately, our goal is to predict organ suitability for transplantation using high-frequency imaging and spectral analysis techniques. To examine the effects of liver ischemia at different temperatures, livers from Wistar rats were surgically excised, immersed in phosphate buffer saline and stored at 4 and 20 °C for 24 h. To mimic organ preservation, livers were excised, flushed with University of Wisconsin (UW) solution and stored at 4 °C for 24 h. Preservation injury was simulated by either not flushing livers with UW solution or, before scanning, allowing livers to reach room temperature. Ultrasound images and corresponding radiofrequency data were collected over the ischemic period. No significant increase in integrated backscatter (~2.5 dBr) was measured for the livers prepared using standard preservation conditions. For all other ischemia models, the integrated backscatter increased by 4-9 dBr demonstrating kinetics dependent on storage conditions. The results provide a possible framework for using high-frequency imaging to non-invasively assess liver preservation injury.

Vlad, Roxana M.; Czarnota, Gregory J.; Giles, Anoja; Sherar, Michael D.; Hunt, John W.; Kolios, Michael C.

2005-01-01

170

Interaction of vortices with ultrasound and the acoustic Faraday effect in type-II superconductors  

SciTech Connect

We study the interaction of sound waves with vortices in type-II superconductors, taking into account pinning and electrodynamic forces between vortices and crystal displacements. We propose ultrasound techniques as a method for obtaining information about vortex dynamics. This is particularly appropiate at low temperatures where transport measurements are ineffective. The changes in sound velocity and attenuation due to vortices, can provide information on the elastic constants of the vortex system and on vortex dissipation, respectively. At low temperatures the Magnus force acting on vortices leads to the {ital acoustic} {ital Faraday} {ital effect}: there is a rotation of the polarization plane of tranverse sound waves propagating along the magnetic field. This effect is linear in the Magnus force and magnetic field in crystals with equivalent {ital a} and {ital b} axes for a field parallel to the {ital c} axis. We discuss how this effect can be measured by means of either pulse-echo techniques or standing sound waves. Also, we show that an ac electromagnetic field acting on the vortex system can generate ultrasound. We calculate the amplitude of the generated sound waves in the linear regime and compare with recent experiments. {copyright} {ital 1996 The American Physical Society.}

Dominguez, D.; Bulaevskii, L. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Ivlev, B. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)]|[Universidad Autonoma de San Luis Potosi, Instituto de Fisica, Alvaro Obregon 64, 78000 San Luis Potosi, San Luis Potosi (Mexico); Maley, M.; Bishop, A.R. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

1996-03-01

171

Combined spectroscopic imaging and chemometric approach for automatically partitioning tissue types in human prostate tissue biopsies  

NASA Astrophysics Data System (ADS)

We have applied Fourier transform infrared (FTIR) spectroscopic imaging, coupling a mercury cadmium telluride (MCT) focal plane array detector (FPA) and a Michelson step scan interferometer, to the investigation of various states of malignant human prostate tissue. The MCT FPA used consists of 64x64 pixels, each 61 micrometers 2, and has a spectral range of 2-10.5 microns. Each imaging data set was collected at 16-1 resolution, resulting in 512 image planes and a total of 4096 interferograms. In this article we describe a method for separating different tissue types contained within FTIR spectroscopic imaging data sets of human prostate tissue biopsies. We present images, generated by the Fuzzy C-Means clustering algorithm, which demonstrate the successful partitioning of distinct tissue type domains. Additionally, analysis of differences in the centroid spectra corresponding to different tissue types provides an insight into their biochemical composition. Lastly, we demonstrate the ability to partition tissue type regions in a different data set using centroid spectra calculated from the original data set. This has implications for the use of the Fuzzy C-Means algorithm as an automated technique for the separation and examination of tissue domains in biopsy samples.

Haka, Abigail S.; Kidder, Linda H.; Lewis, E. Neil

2001-07-01

172

Shearwave dispersion ultrasound vibrometry (SDUV) for measuring tissue elasticity and viscosity  

Microsoft Academic Search

Characterization of tissue elasticity (stiffness) and viscosity has important medical applications because these properties are closely related to pathological changes. Quantitative measurement is more suitable than qualitative measurement (i.e., mapping with a relative scale) of tissue viscoelasticity for diagnosis of diffuse diseases where abnormality is not confined to a local region and there is no normal background tissue to provide

Shigao Chen; M. Urban; C. Pislaru; R. Kinnick; Yi Zheng; Aiping Yao; J. Greenleaf

2009-01-01

173

Optimization of contrast-to-tissue ratio by adaptation of transmitted ternary signal in ultrasound pulse inversion imaging.  

PubMed

Ultrasound contrast imaging has provided more accurate medical diagnoses thanks to the development of innovating modalities like the pulse inversion imaging. However, this latter modality that improves the contrast-to-tissue ratio (CTR) is not optimal, since the frequency is manually chosen jointly with the probe. However, an optimal choice of this command is possible, but it requires precise information about the transducer and the medium which can be experimentally difficult to obtain, even inaccessible. It turns out that the optimization can become more complex by taking into account the kind of generators, since the generators of electrical signals in a conventional ultrasound scanner can be unipolar, bipolar, or tripolar. Our aim was to seek the ternary command which maximized the CTR. By combining a genetic algorithm and a closed loop, the system automatically proposed the optimal ternary command. In simulation, the gain compared with the usual ternary signal could reach about 3.9 dB. Another interesting finding was that, in contrast to what is generally accepted, the optimal command was not a fixed-frequency signal but had harmonic components. PMID:23573167

Ménigot, Sébastien; Girault, Jean-Marc

2013-03-20

174

Optimization of Contrast-to-Tissue Ratio by Adaptation of Transmitted Ternary Signal in Ultrasound Pulse Inversion Imaging  

PubMed Central

Ultrasound contrast imaging has provided more accurate medical diagnoses thanks to the development of innovating modalities like the pulse inversion imaging. However, this latter modality that improves the contrast-to-tissue ratio (CTR) is not optimal, since the frequency is manually chosen jointly with the probe. However, an optimal choice of this command is possible, but it requires precise information about the transducer and the medium which can be experimentally difficult to obtain, even inaccessible. It turns out that the optimization can become more complex by taking into account the kind of generators, since the generators of electrical signals in a conventional ultrasound scanner can be unipolar, bipolar, or tripolar. Our aim was to seek the ternary command which maximized the CTR. By combining a genetic algorithm and a closed loop, the system automatically proposed the optimal ternary command. In simulation, the gain compared with the usual ternary signal could reach about 3.9?dB. Another interesting finding was that, in contrast to what is generally accepted, the optimal command was not a fixed-frequency signal but had harmonic components.

Girault, Jean-Marc

2013-01-01

175

Registration of ultrasound images  

Microsoft Academic Search

In many surgical procedures, ultrasound is used for real- time visualization in order to minimize invasion of healthy tissue. Unfortunately, the exact location of soft tissues and the composition of tissues of interest may be difficult to determine using ultrasound. In interactive image guided surgery (IIGS), the display of present surgical position on preoperative tomographic imags enhances the surgeons locational

Ryan A. Beasley; James D. Stefansic; Alan J. Herline; Louis Guttierez; Robert L. Galloway

1999-01-01

176

Non-invasive determination of tissue thermal parameters from high intensity focused ultrasound treatment monitored by volumetric MRI thermometry.  

PubMed

A method is proposed for estimating the perfusion rate, thermal diffusivity, and the absorption coefficient that influence the local temperature during high intensity focused ultrasound (HIFU) thermotherapy procedures. For this purpose, HIFU heating experiments (N = 100) were performed ex vivo on perfused porcine kidney (N = 5) under different flow conditions. The resulting spatio-temporal temperature variations were measured non-invasively by rapid volumetric MR-temperature imaging. The bio-heat transfer (BHT) model was adapted to describe the spatio-temporal evolution of tissue temperature in the cortex. Absorption and perfusion coefficients were determined by fitting the integrated thermal load (spatial integration of the thermal maps) curves in time with an analytical solution of the BHT equation proposed for single point HIFU heating. Thermal diffusivity was determined independently by analyzing the spatial spread of the temperature in time during the cooling period. Absorption coefficient and thermal diffusivity were found to be independent of flow, with mean and average values of 11.0 +/- 1.85 mm(3) x K x J(-1) and 0.172 +/- 0.003 mm(2) x s(-1), respectively. A linear dependence of the calculated perfusion rate with flow was observed with a slope of 9.20 +/- 0.75 mm(-3). The perfusion was found to act as a scaling term with respect to temperature but with no effect on the spatial spread of temperature which only depends on the thermal diffusivity. All results were in excellent agreement with the BHT model, indicating that this model is suitable to predict the evolution of temperature in perfused organs. This quantitative approach allows for determination of tissue thermal parameters with excellent precision (within 10%) and may thus help in quantifying the influence of perfusion during MR guided high intensity focused ultrasound (MRgHIFU). PMID:19562728

Dragonu, Iulius; de Oliveira, Philippe Lourenço; Laurent, Christophe; Mougenot, Charles; Grenier, Nicolas; Moonen, Chrit T W; Quesson, Bruno

2009-10-01

177

Impact of vascular remodeling on the coronary plaque compositions: An investigation with in vivo tissue characterization using integrated backscatter-intravascular ultrasound  

Microsoft Academic Search

Recent studies have indicated that positive remodeling is strongly associated with development of acute coronary syndrome (ACS). The aim of this study was to compare plaque composition of vascular remodeling patterns by an established in vivo tissue characterization method using integrated backscatter (IB)-intravascular ultrasound (IVUS). The study population consisted of 41 consecutive patients who received IVUS prior to percutaneous coronary

Hiroki Takeuchi; Yoshihiro Morino; Takashi Matsukage; Naoki Masuda; Yota Kawamura; Satoshi Kasai; Tadashi Hashida; Daisuke Fujibayashi; Teruhisa Tanabe; Yuji Ikari

2009-01-01

178

CAROTID ULTRASOUND, BLOOD LIPIDS AND WAIST DETERMINATION CAN PREDICT A FUTURE CORONARY REVASCULARISATION IN THE TYPE 2 DIABETIC COHORT  

Microsoft Academic Search

A b s t r a c t: The aim of the study was to identify incremental values of carotid ultrasound measurements (carotid plaques and stenosis) on the prediction of future coronary revascularization among type 2 diabetic patients. The second objective was to determine the predictive value of the assessment of blood lipids, BMI, abdominal obesity and the ankle-brachial index

Georgievska-Ismail Lj

179

The usefulness of quantitative ultrasound at the hand phalanges in the detection of the different types of nontraumatic fractures  

Microsoft Academic Search

The aim of this retrospective study was to determine whether quantitative ultrasound (QUS) at the hand phalanges has the ability to discriminate between individuals without and with different types of nontraumatic fractures. All women (n = 2466) (age range 38–88 years) not affected by metabolic diseases or under treatment with drugs known to interfere with bone metabolism were divided into

Bogna Drozdzowska; Wojciech Pluskiewicz; Francesca de Terlizzi

2003-01-01

180

The ability of quantitative ultrasound at the calcaneus to identify postmenopausal women with different types of nontraumatic fractures  

Microsoft Academic Search

The aim of the cross-sectional study was to determine if ultrasound (US) measurements of the calcaneus have the ability to predict the risk for fractures and to discriminate between postmenopausal women with and without different types of nontraumatic fractures. All women (n = 1129, age range 40 to 87 years) were divided into group 1, created by 656 women with

Bogna Drozdzowska; Wojciech Pluskiewicz

2002-01-01

181

Harmonic Band Spectrum Analysis of Backscattered Ultrasound from Lesioned and Normal Tissue  

Microsoft Academic Search

HIFU dose curves (lesion size vs. exposure parameters) exhibit scatter because of local variations in the acoustic properties of tissue. Therefore, clinical applications of HIFU, such as cardiac and cancer ablation, will benefit from the ability to distinguish treated from normal tissue, which can provide the surgeon with lesion monitoring. However, HIFU lesions, especially protein-denaturing lesions (PDLs), may be difficult

Robert Muratore; Frederic L. Lizzi; Ronald H. Silverman

2006-01-01

182

Ultrasound Dynamic Micro-Elastography Applied to the Viscoelastic Characterization of Soft Tissues and Arterial Walls  

Microsoft Academic Search

Quantitative noninvasive methods that provide in vivo assessment of mechanical characterization of living tissues, organs and artery walls are of interest because information on their viscoelastic properties in the presence of disease can affect diagnosis and treatment options. This article proposes the dynamic micro-elastography (DME) method to characterize viscoelasticity of small homogeneous soft tissues, as well as the adaptation of

Cédric Schmitt; Anis Hadj Henni; Guy Cloutier

2010-01-01

183

Feasibility and effect of ultrasound microbubble-mediated wild-type p53 gene transfection of HeLa cells  

PubMed Central

Gene therapy holds great promise for the treatment of diseases. The key problem of gene therapy is the choice of an effective vector. Ultrasound-mediated microbubble technique (UMMT) has already shown promising applications in numerous types of tumors apart from cervical carcinoma. In the present study, according to the results of an MTT assay, we initially chose an ultrasound intensity of 0.5 W/cm2, an ultrasound exposure time of 30 sec and a microbubble concentration of 10% as the optimum experimental condition for wtp53 plasmid transfection into HeLa cells. To further investigate the transfection efficiency of ultrasound combined with microbubbles, RT-PCR analysis was used to examine the mRNA level of p53. The transfection efficiency in the plasmid plus microbubbles and ultrasound group was significantly higher than that of the other groups. Following transfection of the wtp53 gene, flow cytometric analysis showed that the cell cycle of HeLa cells was arrested in the G1 phase. The results of the present study suggest that UMMT, a new gene delivery system, increases the transfection efficiency of the wtp53 gene. Moreover, the growth of HeLa cells was arrested by introducing wtp53. This study may afford a new trend for the gene therapy of cervical carcinoma.

CHEN, WEN-JUAN; XIONG, ZHENG-AI; TANG, YAN; DONG, PEI-TING; LI, PAN; WANG, ZHI-GANG

2012-01-01

184

Angiotensin II type 1 receptor expression in human breast tissues.  

PubMed Central

We demonstrate the expression of angiotensin II type 1 (AT1) receptors in normal and diseased human breast tissues. Using monoclonal antibody 6313/G2, directed against a specific sequence in the extracellular domain of the AT1 receptor, immunocytochemical analysis revealed positive immunoreactivity in membrane and cytoplasm of specific cell types. Immunoblotting of solubilized proteins separated by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) from benign and malignant tumours identified a single immunoreactive species with a molecular mass of approximately 60 kDa, consistent with that of the mature glycosylated receptor. In studies of [125I]angiotensin II binding using breast membrane preparations, concentrations of specific angiotensin II binding sites were found to range from 1.8 to 100 fmol mg(-1) protein, with a K(d) of approximately 60 nM. Most of the specifically bound [125I]angiotensin II was displaced by losartan, a specific angiotensin II type 1 receptor antagonist, while less was displaced by the AT2 receptor type antagonist, CGP42112A, thus confirming the prevalence of AT1 receptors in this tissue type. These data suggest that the renin-angiotensin system may be involved in normal and abnormal breast tissue function. Images Figure 1 Figure 4

Inwang, E. R.; Puddefoot, J. R.; Brown, C. L.; Goode, A. W.; Marsigliante, S.; Ho, M. M.; Payne, J. G.; Vinson, G. P.

1997-01-01

185

Study of Tissue Phantoms, Tissues, and Contrast Agent with the Biophotoacoustic Radar and Comparison to Ultrasound Imaging for Deep Subsurface Imaging  

NASA Astrophysics Data System (ADS)

In this study, the imaging capability of our wide-spectrum frequency-domain photoacoustic (FD-PA) imaging alias "photoacoustic radar" methodology for imaging of soft tissues is explored. A practical application of the mathematical correlation processing method with relatively long (1 ms) frequency-modulated optical excitation is demonstrated for reconstruction of the spatial location of the PA sources. Image comparison with ultrasound (US) modality was investigated to see the complementarity between the two techniques. The obtained results with a phased array probe on tissue phantoms and their comparison to US images demonstrated that the FD-PA technique has strong potential for deep subsurface imaging with excellent contrast and high signal-to-noise ratio. FD-PA images of blood vessels in a human wrist and an in vivo subcutaneous tumor in a rat model are presented. As in other imaging modalities, the employment of contrast agents is desirable to improve the capability of medical diagnostics. Therefore, this study also evaluated and characterized the use of Food and Drug Administration (FDA)-approved superparamagnetic iron oxide nanoparticles (SPION) as PA contrast agents.

Alwi, R.; Telenkov, S.; Mandelis, A.; Gu, F.

2012-11-01

186

Endoscopic-ultrasound-guided tissue sampling facilitates the detection of local recurrence and extra pelvic metastasis in pelvic urologic malignancy.  

PubMed

Pelvic lymph node dissection is the gold standard for assessing nodal disease in prostate or bladder cancer and is superior to CT, MRI and PET staging. Endoscopic ultrasound (EUS) provides an alternative, less invasive method of cytohistologic material acquisition, but its performance in pelvic urologic malignancy is unknown. Therefore, our aim was to evaluate the diagnostic accuracy of EUS guided tissue sampling for these malignancies when compared to a composite cytohistologic and surgical gold standard. A median of 3 FNA passes were performed (n = 19 patients) revealing a sensitivity, specificity, PPV and NPV of 94.4% (72-99), 100% (2-100), 100% (80-100) and 50% (1-98) respectively. The perirectal space was the most frequently sampled location irrespective of the primary urological cancer origin. Final diagnosis established by EUS tissue sampling included bladder cancer (n = 1), bladder cancer local recurrence (n = 8), bladder cancer extra pelvic metastases (n = 1), prostate cancer (n = 2), prostate cancer local recurrence (n = 4), prostate cancer extra pelvic metastases (n = 1), testicular cancer extra pelvic metastases (n = 1) and a benign seminal vesicle (n = 1). EUS guided sampling of the gut wall, lymph nodes, or perirectal space yields suitable diagnostic material to establish the presence of primary, local recurrence or extra pelvic metastases of pelvic urologic malignancy. PMID:22778538

Gleeson, Ferga C; Clain, Jonathan E; Karnes, R Jeffrey; Rajan, Elizabeth; Topazian, Mark D; Wang, Kenneth K; Levy, Michael J

2012-06-19

187

Characterization of tissue-simulating phantom materials for ultrasound-guided needle procedures  

NASA Astrophysics Data System (ADS)

Needle biopsies are standard protocols that are commonly performed under ultrasound (US) guidance or computed tomography (CT)1. Vascular access such as central line insertions, and many spinal needle therapies also rely on US guidance. Phantoms for these procedures are crucial as both training tools for clinicians and research tools for developing new guidance systems. Realistic imaging properties and material longevity are critical qualities for needle guidance phantoms. However, current commercially available phantoms for use with US guidance have many limitations, the most detrimental of which include harsh needle tracks obfuscating US images and a membrane comparable to human skin that does not allow seepage of inner media. To overcome these difficulties, we tested a variety of readily available media and membranes to evaluate optimal materials to fit our current needs. It was concluded that liquid hand soap was the best medium, as it instantly left no needle tracks, had an acceptable depth of US penetration and portrayed realistic imaging conditions, while because of its low leakage, low cost, acceptable durability and transparency, the optimal membrane was 10 gauge vinyl.

Buchanan, Susan; Moore, John; Lammers, Deanna; Baxter, John; Peters, Terry

2012-02-01

188

Partial shrinkage of venous tissues near valves using High Intensity Focused Ultrasound  

Microsoft Academic Search

The cross-section of a vein can be reduced by exposing the collagen of the vein wall to high temperature (85° C) for a few seconds. Partial shrinkage of the vein is appropriate for correcting deformations of valvular tissues that can cause the abnormal blood reflux which is the main cause of varicose veins and Superficial Venous Insufficiency. Due to its

Samuel Pichardo; Laura Curiel; René Milleret; Olivier Pichot; François Lacoste; Jean-Yves Chapelon

2005-01-01

189

Localisation of caveolin in mammary tissue depends on cell type.  

PubMed

Caveolins, components of caveolae, are expressed in mammary tissue. In order to determine whether caveolins are present in different mammary cell types and whether their localisation depends on the physiological stage or species, cav-1 and cav-2 were characterised by immunoblotting in mammary tissues from the mouse, ewe and rabbit and localised, by immunofluorescence and electron microscopy, in mammary tissues from the mouse and ewe. At all the physiological stages studied, cav-1 and cav-2 were present in endothelial and myoepithelial cells in which flask-shaped caveolae were abundant. However, labelling of cav-1 and cav-2 associated with small vesiculo-tubular structures (including those close to lipid droplets) was low in epithelial cells. To study the possible association of cav-1 with lipid droplets, lactating ewe mammary fragments were treated in vitro with brefeldin A. This treatment did not modify the association of cav-1-labelled structures with lipid droplets. Finally, HC11 and MCF-10A mammary cell lines were treated with oleic acid. The total quantity of cav-1 was little affected by the treatment, although the lipid droplet labelling of cav-1 was amplified in MCF-10A cells. Thus, the synthesis and localisation of caveolins are mostly dependent upon the cell types of mammary tissue and upon their state of differentiation. PMID:17468894

Hue-Beauvais, Catherine; Péchoux, Christine; Bouguyon, Edwige; Chat, Sophie; Truchet, Sandrine; Pauloin, Alain; Le Gouar, Yann; Ollivier-Bousquet, Michèle

2007-02-14

190

No effect of bipolar interferential electrotherapy and pulsed ultrasound for soft tissue shoulder disorders: a randomised controlled trial  

PubMed Central

OBJECTIVE—To assess the efficacy of bipolar interferential electrotherapy (ET) and pulsed ultrasound (US) as adjuvants to exercise therapy for soft tissue shoulder disorders (SD).?METHODS—Randomised placebo controlled trial with a two by two factorial design plus an additional control group in 17 primary care physiotherapy practices in the south of the Netherlands. Patients with shoulder pain and/or restricted shoulder mobility, because of a soft tissue impairment without underlying specific or generalised condition, were enrolled if they had not recovered after six sessions of exercise therapy in two weeks. They were randomised to receive (1) active ET plus active US; (2) active ET plus dummy US; (3) dummy ET plus active US; (4) dummy ET plus dummy US; or (5) no adjuvants. Additionally, they received a maximum of 12 sessions of exercise therapy in six weeks. Measurements at baseline, 6 weeks and 3, 6, 9, and 12 months later were blinded for treatment. Outcome measures: recovery, functional status, chief complaint, pain, clinical status, and range of motion.?RESULTS—After written informed consent 180 patients were randomised: both the active treatments were given to 73 patients, both the dummy treatments to 72 patients, and 35 patients received no adjuvants. Prognosis of groups appeared similar at baseline. Blinding was successfully maintained. At six weeks seven patients (20%) without adjuvants reported very large improvement (including complete recovery), 17 (23%) and 16 (22%) with active and dummy ET, and 19 (26%) and 14 (19%) with active and dummy US. These proportions increased to about 40% at three months, but remained virtually stable thereafter. Up to 12 months follow up the 95% CI for differences between groups for all outcomes include zero.?CONCLUSION—Neither ET nor US prove to be effective as adjuvants to exercise therapy for soft tissue SD.??

van der Heijden, G. J M G; Leffers, P.; Wolters, P.; Verheijden, J.; van Mameren, H.; Houben, J.; Bouter, L.; Knipschild, P.

1999-01-01

191

Assessment of the effects of ultrasound-mediated glucose on permeability of normal, benign, and cancerous human lung tissues with the Fourier-domain optical coherence tomography  

NASA Astrophysics Data System (ADS)

The objective of this study was to evaluate the effects of ultrasound-mediated analyte diffusion on permeability of normal, benign, and cancerous human lung tissue in vitro and to find more effective sonophoretic (SP) delivery in combination with the optical clearing agents (OCAs) method to distinguish normal and diseased lung tissues. The permeability coefficients of SP in combination with OCAs diffusion in lung tissue were measured with Fourier-domain optical coherence tomography (FD-OCT). 30% glucose and SP with a frequency of 1 MHz and an intensity of 0.80 W/cm2 over a 3 cm probe was simultaneously applied for 15 min. Experimental results show that the mean permeability coefficients of 30% glucose/SP were found to be (2.01±0.21)×10-5 cm/s from normal lung (NL) tissue, (2.75±0.28)×10-5 cm/s from lung benign granulomatosis (LBG) tissue, (4.53±0.49)×10-5 cm/s from lung adenocarcinoma tumor (LAT) tissue, and (5.81±0.62)×10-5 cm/s from lung squamous cell carcinoma (LSCC) tissue, respectively. The permeability coefficients of 30% glucose/SP increase approximately 36.8%, 125.4%, and 189.1% for the LBG, LAT, and LSCC tissue compared with that for the NL tissue, respectively. There were statistically significant differences in permeability coefficients of 30% glucose/SP between LBG and NL tissue (p<0.05), between LAT and NL tissue (p<0.05), and between LSCC and NL tissue (p<0.05). The results suggest that the OCT functional imaging technique to combine an ultrasound-OCAs combination method could become a powerful tool in early diagnosis and monitoring of changed microstructure of pathologic human lung tissue.

Wei, Huajiang; Wu, Guoyong; Guo, Zhouyi; Yang, Hongqin; He, Yonghong; Xie, Shusen; Guo, Xiao

2012-11-01

192

Assessment of the effects of ultrasound-mediated glucose on permeability of normal, benign, and cancerous human lung tissues with the Fourier-domain optical coherence tomography.  

PubMed

The objective of this study was to evaluate the effects of ultrasound-mediated analyte diffusion on permeability of normal, benign, and cancerous human lung tissue in vitro and to find more effective sonophoretic (SP) delivery in combination with the optical clearing agents (OCAs) method to distinguish normal and diseased lung tissues. The permeability coefficients of SP in combination with OCAs diffusion in lung tissue were measured with Fourier-domain optical coherence tomography (FD-OCT). 30% glucose and SP with a frequency of 1 MHz and an intensity of 0.80??W/cm2 over a 3 cm probe was simultaneously applied for 15 min. Experimental results show that the mean permeability coefficients of 30% glucose/SP were found to be (2.01±0.21)×10(-5)??cm/s from normal lung (NL) tissue, (2.75±0.28)×10(-5)??cm/s from lung benign granulomatosis (LBG) tissue, (4.53±0.49)×10(-5)??cm/s from lung adenocarcinoma tumor (LAT) tissue, and (5.81±0.62)×10(-5)??cm/s from lung squamous cell carcinoma (LSCC) tissue, respectively. The permeability coefficients of 30% glucose/SP increase approximately 36.8%, 125.4%, and 189.1% for the LBG, LAT, and LSCC tissue compared with that for the NL tissue, respectively. There were statistically significant differences in permeability coefficients of 30% glucose/SP between LBG and NL tissue (p<0.05), between LAT and NL tissue (p<0.05), and between LSCC and NL tissue (p<0.05). The results suggest that the OCT functional imaging technique to combine an ultrasound-OCAs combination method could become a powerful tool in early diagnosis and monitoring of changed microstructure of pathologic human lung tissue. PMID:23117801

Wei, Huajiang; Wu, Guoyong; Guo, Zhouyi; Yang, Hongqin; He, Yonghong; Xie, Shusen; Guo, Xiao

2012-11-01

193

Epicardial adipose tissue thickness in type 1 diabetic patients.  

PubMed

Insulin resistance is getting important in the course of type 1 diabetes mellitus. Visceral fat depot is associated with insulin resistance and assessment of epicardial fat thickness is a way of measuring visceral fat. The aim of the study was to measure epicardial adipose tissue (EAT) thickness and to determine its relationship with waist-hip-ratio (WHR) and estimated glucose disposal rate (eGDR) in adult type 1 diabetic patients. Thirty-six type 1 diabetic patients (aged 31±8 years; Female/Male: 22/14) and 43 age, gender and BMI matched healthy controls were included. Fasting blood glucose (FBG), hemoglobin A1c, and lipid profiles were measured. Waist-hip-ratio (WHR) was calculated. Daily insulin dose/kg of patients were recorded and eGDR of all subjects was calculated. Epicardial adipose tissue (EAT) thickness was evaluated by echocardiography. EAT thickness of the type 1 diabetic patients was significantly higher than controls (3.30±1.06 vs. 2.30±0.34 mm, P<0.0001). EAT thickness was correlated with age (P=0.05; r=0.35), WHR (P=0.003; r=0.67), daily insulin dose/kg (r=0.45, P=0.005), and eGDR (r=-0.55, P=0.0004). Multivariate analysis revealed WHR and eGDR to be related to EAT among age, WHR, daily insulin dose/kg, eGDR, FBG, and hemoglobin A1c (r2 of the model=0.64). Epicardial adipose tissue thickness is increased in type 1 diabetic patients compared to controls and is related to WHR and eGDR in this group of patients. This measurement may point to the presence of insulin resistance in type 1 diabetic patients. PMID:21553302

Yaz?c?, Dilek; Özben, Beste; Yavuz, Dilek; Deyneli, O?uzhan; Ayd?n, Hasan; Tarcin, Özlem; Akal?n, Sema

2011-05-08

194

Quantitative ultrasound bone measurements in pre-pubertal children with type 1 diabetes.  

PubMed

This case-control study aimed to assess bone status in children with type 1 diabetes mellitus (T1DM). Fifty-seven pre-pubertal patients (37 boys, aged 7.9 ± 2.5 years, T1DM duration 3.1 ± 1.6 years) and 171 age-matched healthy controls (111 boys) were studied. Quantitative ultrasound (QUS) was used to measure amplitude dependent speed of sound (Ad-SoS) at hand phalanges (expressed as standard deviation score [SDS]). Anthropometric and disease-related data (including mean HbA(1c) from whole T1DM duration [T], last year [Y], examination day [D]) were collected. Mean Ad-SoS SDS in patients -0.13 ± 1.32 (95% confidence interval [CI] -0.48, 0.22) was similar to that of controls. Subgroups discriminated according to HbA(1c) D, Y and T (cut-off 7.0%) did not differ regarding analyzed parameters. In patients, Ad-SoS SDS was comparable for both genders. Multivariable stepwise regression analysis showed significant negative influence of diabetes duration on Ad-SoS SDS. QUS findings in pre-pubertal children with T1DM do not differ from those in healthy children. Disease duration seems to affect negatively Ad-SoS SDS. However, independent prospective studies are needed to elucidate the true associations. PMID:22542259

Chobot, Agata P; Haffke, Anna; Polanska, Joanna; Halaba, Zenon P; Deja, Grazyna; Jarosz-Chobot, Przemyslawa; Pluskiewicz, Wojciech

2012-04-27

195

Type III collagen metabolism in soft tissue sarcomas.  

PubMed Central

Sera of 85 patients with benign soft tissue lesions or sarcomas of soft tissues were investigated for a collagen metabolite, the aminoterminal propeptide of type III procollagen (PIIINP). Patients were divided into three groups: benign soft tissue lesions (n = 39), localised (n = 29) and metastatic (n = 18) soft tissue sarcomas (STS). Values of PIIINP above the reference range were found in 15%, 28% and 50% of the respective groups. The difference in the concentration of PIIINP was statistically significant between the benign lesions and the localised sarcomas; P = 0.05, and between the benign lesions and the metastatic sarcomas; P less than 0.001. In localised sarcomas there was a correlation between PIIINP and bone-involvement (r = 0.61, P = 0.002) and in metastatic disease between PIIINP and liver metastases (r = 0.77, P less than 0.001). In localised sarcomas the overall survival for patients with a value of PIIINP above the reference range was significantly poorer (P = 0.03) than for patients with values within the reference range, even after stratification for the histological malignancy grade of the tumours (P = 0.04).

Wiklund, T. A.; Elomaa, I.; Blomqvist, C. P.; Risteli, L.; Risteli, J.

1992-01-01

196

Characterizing tissue microstructure using an ultrasound system-independent spatial autocorrelation function  

NASA Astrophysics Data System (ADS)

The research described in this dissertation is related to characterization of tissue microstructure using a system- independent spatial autocorrelation function (SAF). The function was determined using a reference phantom method, which employed a well-defined ``point- scatterer'' reference phantom to account for instrumental factors. The SAF's were estimated for several tissue-mimicking (TM) phantoms and fresh dog livers. Both phantom tests and in vitro dog liver measurements showed that the reference phantom method is relatively simple and fairly accurate, providing the bandwidth of the measurement system is sufficient for the size of the scatterer being involved in the scattering process. Implementation of this method in clinical scanner requires that distortions from patient's body wall be properly accounted for. The SAF's were estimated for two phantoms with body-wall-like distortions. The experimental results demonstrated that body wall distortions have little effect if echo data are acquired from a large scattering volume. One interesting application of the SAF is to form a ``scatterer size image''. The scatterer size image may help providing diagnostic tools for those diseases in which the tissue microstructure is different from the normal. Another method, the BSC method, utilizes information contained in the frequency dependence of the backscatter coefficient to estimate the scatterer size. The SAF technique produced accurate scatterer size images of homogeneous TM phantoms and the BSC method was capable of generating accurate size images for heterogeneous phantoms. In the scatterer size image of dog kidneys, the contrast-to-noise-ratio (CNR) between renal cortex and medulla was improved dramatically compared to the gray- scale image. The effect of nonlinear propagation was investigated by using a custom-designed phantom with overlaying TM fat layer. The results showed that the correlation length decreased when the transmitting power increased. The measurement results support the assumption that nonlinear propagation generates harmonic energies and causes underestimation of scatterer diameters. Nonlinear propagation can be further enhanced by those materials with high B/A value-a parameter which characterizes the degree of nonlinearity. Nine versions of TM fat and non-fat materials were measured for their B/A values using a new measurement technique, the ``simplified finite amplitude insertion substitution'' (SFAIS) method.

Dong, Fang

1999-09-01

197

Type I collagen synthesis and degradation in peritendinous tissue after exercise determined by microdialysis in humans  

PubMed Central

Physical activity is known to increase type I collagen synthesis measured as the concentration of biomarkers in plasma. By the use of microdialysis catheters with a very high molecular mass cut-off value (3000 kDa) we aimed to determine local type I collagen synthesis and degradation in the peritendinous region by measuring interstitial concentrations of a collagen propeptide (PICP; 100 kDa) and a collagen degradation product (ICTP; 9 kDa) as well as an inflammatory mediator (PGE2). Seven trained human runners were studied before and after (2 and 72 h) 3 h of running (36 km). Two microdialysis catheters were placed in the peritendinous space ventral to the Achilles' tendon under ultrasound guidance and perfused with a Ringer-acetate solution containing 3H-labelled human type IV collagen and [15-3H(N)]PGE2 for in vivo recovery determination. Relative recovery was 37–59% (range of the s.e.m. values) for both radioactively labelled substances. PICP concentration decreased in both interstitial peritendinous tissue and arterial blood immediately after exercise, but rose 3-fold from basal 72 h after exercise in the peritendinous tissue (55 ± 10 ?g l?1, mean ± s.e.m. (rest) to 165 ± 40 ?g l?1 (72 h), P < 0·05) and by 25% in circulating blood (160 ± 10 ?g l?1 (rest) to 200 ± 12 ?g l?1 (72 h), P < 0·05). ICTP concentration did not change in blood, but decreased transiently in tendon-related tissue during early recovery after exercise only. PGE2 concentration increased in blood during running, and returned to baseline in the recovery period, whereas interstitial PGE2 concentration was elevated in the early recovery phase. The findings of the present study indicate that acute exercise induces increased formation of type I collagen in peritendinous tissue as determined with microdialysis and using dialysate fibre with a very high molecular mass cut-off. This suggests an adaptation to acute physical loading also in non-bone-related collagen in humans.

Langberg, Henning; Skovgaard, Dorthe; Petersen, Lars J; Bulow, Jens; Kjaer, Michael

1999-01-01

198

Comparison of continuous vs. pulsed focused ultrasound in treated muscle tissue as evaluated by magnetic resonance imaging, histological analysis, and microarray analysis  

Microsoft Academic Search

The purpose of this study was to investigate the effect of different application modes of high intensity focused ultrasound\\u000a (HIFU) to muscle tissue. HIFU was applied to muscle tissue of the flank in C3H\\/Km mice. Two dose regimes were investigated,\\u000a a continuous HIFU and a short-pulsed HIFU mode. Three hours after HIFU treatment pre- and post-contrast T1-weighted, T2-weighted\\u000a images and

Walter Hundt; Esther L. Yuh; Silke Steinbach; Mark D. Bednarski; Samira Guccione

2008-01-01

199

Automatic Control of Focal Trajectory and Intensity of Ultrasound Phased Arrays in Minimum-Time Delivery of Thermal Dose with Imposed Normal Tissue Constraints  

NASA Astrophysics Data System (ADS)

A prototype treatment control system that automatically selects location and intensity of the ultrasound focal zone to deliver the prescribed thermal dose to the target in minimum time without violating explicitly-imposed normal tissue safety constraints is developed. The results of its initial evaluation in a computer-simulated treatment of a realistic three-dimensional breast cancer patient, reported in this paper, illustrate salient features of the developed prototype, which are necessary to minimize the treatment duration while simultaneously satisfying the normal tissue safety constraints.

Niu, Ran; Blankespoor, Adam; Moellmer, Jeff; Roemer, Robert; Skliar, Mikhail

2007-05-01

200

In Vivo Characterization of Pancreatic and Lymph Node Tissue using Endoscopic Ultrasound Spectrum Analysis: Validation Study  

PubMed Central

Background Quantitative spectral analysis of the radio-frequency (RF) signals that underlie grayscale EUS images can be used to provide additional, objective information about tissue state. Objective Our purpose was to validate RF spectral analysis as a method to distinguish between (1) benign and malignant lymph nodes and (2) normal pancreas (NP), chronic pancreatitis (CP) and pancreatic cancer (PC). Design & Setting A prospective validation study of eligible patients was conducted to compare with pilot study RF data. Patients Forty-three patients underwent EUS of the esophagus, stomach, pancreas, and surrounding intra-abdominal and mediastinal lymph nodes (19 from previous pilot study and 24 additional patients). Main Outcome Measurements Midband fit, slope, intercept, and correlation coefficient from a linear regression of the calibrated RF power spectra were determined. Results Discriminant analysis of mean pilot-study parameters was then performed to classify validation-study parameters. For benign vs. malignant lymph nodes, midband-fit and intercept (both with t-test p < 0.058) provided classification with 67% accuracy and area under ROC curve (AUC) of 0.86. For diseased vs. NP, midband-fit and correlation coefficient (both with ANOVA p < 0.001) provided 93% accuracy and AUC of 0.98. For PC vs. CP, the same parameters provided 77% accuracy and AUC of 0.89. Results improved further when classification was performed with all data. Limitations Moderate sample size and spatial averaging inherent to the technique. Conclusions This study confirms that mean spectral parameters provide a non-invasive method to quantitatively discriminate benign and malignant lymph nodes as well as normal and diseased pancreas.

Kumon, Ronald E.; Pollack, Michael J.; Faulx, Ashley L.; Olowe, Kayode; Farooq, Farees T.; Chen, Victor K.; Zhou, Yun; Wong, Richard C. K.; Isenberg, Gerard A.; Sivak, Michael V.; Chak, Amitabh; Deng, Cheri X.

2009-01-01

201

Insulin action in adipose tissue in type 1 diabetes  

PubMed Central

Background: Insulin action has been reported to be normal in type 1 diabetic patients. However, some studies have reported an insulin resistance state in these patients. The aim of this study was to investigate insulin resistance in a group of type 1 diabetic patients. We studied the insulin action in adipose tissue and analyzed the effects of duration of disease, body mass index (BMI), and glycosylated hemoglobin on insulin action at the receptor and postreceptor levels in adipocytes. Methods: Nine female type 1 diabetic patients with different durations of disease and eight nondiabetic female patients of comparable age and BMI were studied. 125I-insulin binding and U-[14C]-D-glucose transport was measured in a sample of subcutaneous gluteus adipose tissue obtained by open surgical biopsy from each subject. Results: The duration of disease was negatively correlated with both 125I-insulin binding capacity (r = ?0.70, P < 0.05) and basal and maximum insulin-stimulated glucose transport (r = ?0.87, P < 0.01, and r = ?0.88, P < 0.01, respectively). Maximum specific 125I-insulin binding to the receptors in adipocytes was higher in the group of patients with a shorter duration of disease (P < 0.01). Basal and maximum insulin-stimulated glucose transport was significantly higher in the group with less than 5 years of disease (P < 0.01). No correlation was found between BMI and insulin action. Conclusion: Female type 1 diabetic patients have normal insulin action. There is a high glucose uptake in the early phase of the disease, although a longer duration of disease appears to be a contributing factor to a decrease in insulin action in these patients, and involving both receptor and postreceptor mechanisms.

Arrieta-Blanco, Francisco; Botella-Carretero, Jose Ignacio; Iglesias, Pedro; Balsa, Jose Antonio; Zamarron, Isabel; De la Puerta, Cristina; Arrieta, Juan Jose; Ramos, Francisco; Vazquez, Clotilde; Rovira, Adela

2011-01-01

202

Chirp-encoded excitation for dual-frequency ultrasound tissue harmonic imaging.  

PubMed

Dual-frequency (DF) transmit waveforms comprise signals at two different frequencies. With a DF transmit waveform operating at both fundamental frequency (f(0)) and second-harmonic frequency (2f(0)), tissue harmonic imaging can be simultaneously performed using not only the conventional 2f(0) second-harmonic signal but also using the f(0 )frequency-difference harmonic signal. Nonetheless, when chirp excitation is incorporated into the DF transmit waveform for harmonic SNR improvement, a particular waveform design is required to maintain the bandwidth of the f(0) harmonic signal. In this study, two different DF chirp waveforms are proposed to produce equal harmonic bandwidth at both the f(0) and 2f(0) frequencies to achieve speckle reduction by harmonic spectral compounding and to increase harmonic SNR for enhanced penetration and sensitivity. The UU13 waveform comprises an up-sweeping f(0) chirp and an up-sweeping 2f(0) chirp with triple bandwidth, whereas the UD11 waveform includes an up-sweeping f(0) chirp and a down-sweeping 2f(0) chirp with equal bandwidth. Experimental results indicate that the UU13 tends to suffer from a high range side lobe level resulting from 3f(0) interference. Consequently, the 2f(0) harmonic envelopes of the UD11 and the UU13 waveforms have compression qualities of 87% and 77%, respectively, when the signal bandwidth is 30%. When the bandwidth increases to 50%, the compression quality of the 2f(0) harmonic envelope degrades to 78% and 54%, respectively, for the UD11 and the UU13 waveforms. The compression quality value of the f0 harmonic envelope remains similar between the two DF transmit waveforms for all signal bandwidths. B-mode harmonic images also show that the UD11 is less contaminated by range side lobe artifacts than is the UU13. Compared with a short pulse with equal bandwidth, the UD11 waveform not only preserves the same spatial resolution after compression but also improves the image SNR by about 10 dB. Moreover, the image contrast-to-noise ratio (CNR), defined as the ratio of the mean to the standard deviation of image intensity in the speckle region, can be increased from 1.0 to about 1.2 when DF spectral compounding is performed. Therefore, it is concluded that the UD11 waveform is a potential solution for chirp-encoded DF harmonic imaging. PMID:23192805

Shen, Che-Chou; Lin, Chin-Hsiang

2012-11-01

203

Type 1 hypersensitivity reactions in reconstructed tissues using syngeneic cell types.  

PubMed Central

1. Type 1 hypersensitivity reactions in response to antigen challenge have been measured as short circuit current (SCC) responses in reconstructed tissues consisting of syngeneic cell types. 2. In all instances reconstructed tissues consisted of an epithelial monolayer grown on collagen-coated Millipore filters and a pad of peritoneal cells. Monolayers were formed of either HCA-7 or HCA-7-Col 1 cells derived from a human adenocarcinoma. Peritoneal cells were derived from rats or guinea-pigs sensitized to either ovalbumin or beta-lactoglobulin. 3. The SCC responses of the monolayers were dependent upon the 'concentration' of peritoneal cells in the reconstructed tissue. The threshold concentration was 0.4 X 10(6) cells when rat peritoneal cells are combined with an epithelial monolayer of 0.2 cm2. 4. The SCC responses in response to antigen challenge were selectively inhibited by the H1-receptor antagonist, mepyramine. Similarly the effects of exogenously applied histamine were antagonised by mepyramine. 5. The responses to antigen challenge were not inhibited by tetrodotoxin in reconstructed tissues. This result is in contrast to that with isolated intestinal epithelia from sensitized animals where tetrodotoxin inhibits the SCC responses to external field stimulation and to challenge with antigens. The consequences of these results for understanding the mechanisms of epithelial Type 1 hypersensitivity reactions are discussed. Suggestions are made to illustrate how the methods developed here may be employed to ask questions about the nature of mediators released and the types of cell responsible in human disease conditions.

Baird, A. W.; Cuthbert, A. W.; MacVinish, L. J.

1987-01-01

204

Intravascular ultrasound  

MedlinePLUS

IVUS; Ultrasound - coronary artery; Endovascular ultrasound; Intravascular echocardiography ... A tiny ultrasound wand is attached to the top of a tiny tube called a catheter. This ultrasound catheter is inserted ...

205

Duplex ultrasound  

MedlinePLUS

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

206

Post-processing of polymer foam tissue scaffolds with high power ultrasound: A route to increased pore interconnectivity, pore size and fluid transport.  

PubMed

The aim of this work is to demonstrate that the structural and fluidic properties of polymer foam tissue scaffolds, post-fabrication but prior to the introduction of cells, can be engineered via exposure to high power ultrasound. Our analysis is supported by measurements of fluid uptake during insonification and imaging of the scaffold microstructure via X-ray computed tomography, scanning electron microscopy and acoustic microscopy. The ultrasonic treatment is performed with a frequency of 30kHz, average intensities up to 80,000 Wm(-2) and exposure times up to 20h. The treatment is found to increase the mean pore size by over 10%. More striking is the improvement in fluid uptake: for scaffolds with only 40% water uptake via standard immersion techniques, we can routinely achieve full saturation of the scaffold over approximately one hour of exposure. These desirable modifications occur with negligible loss of scaffold integrity and mass, and are optimized when the ultrasound treatment is coupled to a pre-wetting stage with ethanol. Our findings suggest that high power ultrasound is highly targeted towards flow obstructions in the scaffold architecture, thereby providing an efficient means to promote pore interconnectivity and fluid transport in thick foam tissue scaffolds. PMID:24094193

Watson, N J; Johal, R K; Glover, Z; Reinwald, Y; White, L J; Ghaemmaghami, A M; Morgan, S P; Rose, F R A J; Povey, M J W; Parker, N G

2013-08-07

207

Tissue-type plasminogen activator gene targets thrombolysis in atriums.  

PubMed

Our previous investigations showed that retroviral gene transfer of tissue-type plasminogen activator (tPA) effectively targeted thrombolysis in vitro and in the model of inferior caval veins of rabbits. This study is to identify the target thrombolysis of retroviral vector recombinant pLEGFP-N1-tPA transferred into the tissue around the Dacron patch (the same materials making of the ring of mechanical valve) in left atriums of rabbits. 70 Dacron patches were transplanted into the left atriums of 70 New Zealand white rabbits. The rabbits were randomly divided into three groups according to the different handling methods, including local pLEGFP-N1-tPA transferred group (gene therapy group, 30 animals), pLEGFP-N1 transferred group (control group, 20 animals), medium DMEM + 10% neonate calf serum (NCS) injected group (blank control group, 20 animals). Samples of blood, Dacron pieces and left atriums (auricles) wall from half of above in each group were harvested on second day and another half were harvested on 75th day after surgery. The EGFP expression of harvested left atriums (auricles) wall were observed under the confocal. The thrombi on the surface of Dacron patches were detected by stereoscope and electron microscope. The tPA expression in left atriums (auricles) wall and in blood from left atriums were detected by Western blot and their thrombolysis and activities were observed and calculated in plasma plates. ELISA were used to identify the contents of tPA. No thrombus was seen on the surface of Dacron patches that were transplanted in left atriums by tPA locally transferring around them. Activity and content of tPA were high in local tissue of left atrium and in blood of left atrium. It demonstrated effectively thrombolysis by tPA rapidly, efficiently and long expressing. This puts the foundation of mechanical valve replacement model for tPA gene valve, next. PMID:20924774

Gong, Yongsheng; Wang, Fajiu; Li, Xia; Gao, Zhixin; Zhang, Kailun; Fan, Chen; Liu, Xingen

2010-11-01

208

Usefulness of tissue transglutaminase type 2 antibodies in early pregnancy.  

PubMed

Celiac disease (CD), an autoimmune disease triggered by dietary gluten, is a multi-systemic disorder that primarily results in mucosal damage of the small intestine. Reproductive disorders and pregnancy complications have been associated with CD. Conflicting results have been published concerning CD and the risk of impaired fetal growth with reduced birthweight. The aim of our multicentric, perspective, case-control study was to determine the prevalence of undiagnosed CD in mothers of small for gestational age (SGA) newborns in two regions of Italy. The study included 480 mothers: group A consisted of 284 SGA newborns' mothers and group B consisted of 196 appropriate for gestational age (AGA) newborns' mothers. Tissue transglutaminase type 2 antibodies (TG2) IgA and IgG were measured in blood samples. We diagnosed two new cases of CD in asymptomatic mothers. It may be appropriate to include the TG2 to the panel of prenatal blood test. PMID:22537115

Baldassarre, Maria Elisabetta; Laneve, Annamaria; Fontana, Antonietta; Manca, Fabio; Salvia, Gennaro; Barcaglioni, Patrizia; Cella, Adolfo; Giannuzzo, Silvia; Esposito, Luigi; Capursi, Teresa; Mastrorilli, Carla; Padovano, Alexander; Laforgia, Nicola

2012-04-26

209

Quantitative Ultrasound in Cancer Imaging  

PubMed Central

Ultrasound is a relatively inexpensive, portable, and versatile imaging modality that has a broad range of clinical uses. It incorporates many imaging modes, such as conventional gray-scale “B-mode” imaging to display echo amplitude in a scanned plane; M-mode imaging to track motion at a given fixed location over time; duplex, color, and power Doppler imaging to display motion in a scanned plane; harmonic imaging to display non-linear responses to incident ultrasound; elastographic imaging to display relative tissue stiffness; and contrast-agent imaging with simple contrast agents to display blood-filled spaces or with targeted agents to display specific agent-binding tissue types. These imaging modes have been well described in the scientific, engineering, and clinical literature. A less well-known ultrasonic imaging technology is based on quantitative ultrasound or (QUS), which analyzes the distribution of power as a function of frequency in the original received echo signals from tissue and exploits the resulting spectral parameters to characterize and distinguish among tissues. This article discusses the attributes of QUS-based methods for imaging cancers and providing improved means of detecting and assessing tumors. The discussion will include applications to imaging primary prostate cancer and metastatic cancer in lymph nodes to illustrate the methods.

Feleppa, Ernest J.; Mamou, Jonathan; Porter, Christopher R.; Machi, Junji

2010-01-01

210

Utility of a simplified ultrasound assessment to assess interstitial pulmonary fibrosis in connective tissue disorders - preliminary results  

PubMed Central

Introduction Interstitial pulmonary fibrosis (IPF) is a frequent manifestation in patients with connective tissue disorders (CTD). Recently the ultrasound (US) criterion validity for its assessment has been proposed; however, the US scoring systems adopted include the study of several lung intercostal spaces (LIS), which could be time-consuming in daily clinical practice. The aim of this study was to investigate the utility of a simplified US B-lines scoring system compared with both the US comprehensive assessment and the high-resolution computed tomography (HRCT) findings of IPF in CTD patients. Methods Thirty-six patients with a diagnosis of CTD were enrolled. Each patient underwent chest HRCT and lung US by an experienced radiologist and rheumatologist, respectively. Both comprehensive and simplified US B-lines assessments were scanned. The comprehensive US assessment was performed at 50 LIS level, whereas the simplified US assessment included bilaterally 14 LIS; for the anterior chest: the second LIS along the para-sternal lines, the fourth LIS along the mid-clavear, anterior axillary and mid-axillary lines; for the posterior chest: the eighth LIS along the paravertebral, sub-scapular and posterior axillary lines. For criterion validity, HRCT was considered the gold standard. Feasibility, inter and intra-observer reliability was also investigated. Results A highly significant correlation between comprehensive and simplified US assessment was found (P = 0.0001). A significant correlation was also found between the simplified US assessment and HRCT findings (P = 0.0006). Kappa values for the inter-observer simplified US assessment were in a range from 0.769 to 0.885, whereas the concordance correlation coefficient values for the intra-observer were from 0.856 to 0.955. There was a relevant difference in time spent on comprehensive (mean 23.3 ± SD 4.5 minutes) with respect to the simplified US assessment (mean 8.6 ± SD 1.4) (P < 0.00001). Conclusions Our results provide a new working hypothesis in favor of the utility of a simplified US B-lines assessment as an adjunct method to assess IPF in patients with CTD.

2011-01-01

211

Major Types of Soft Tissue Sarcomas in Children  

MedlinePLUS

... head and neck Infant–19 Smooth muscle Leiomyosarcoma Trunk 15-19 Fibrous tissue Fibrosarcoma Arms and legs ... 19 Blood vessels Infantile hemangio-pericytoma Arms, legs, trunk, head, and neck Infant–4 Synovial tissue (linings ...

212

Temperature estimation with ultrasound  

NASA Astrophysics Data System (ADS)

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

Daniels, Matthew

213

Brief Communication: Pancreatic-Type Tissue in Livers of Rats Fed Polychlorinated Biphenyls.  

National Technical Information Service (NTIS)

Pancreatic-type tissue in lives of Sherman strain rats is described. This lesion has not been reported previously. The pancreatic-type tissue was observed in livers of rats fed polychlorinated biphenyls (Aroclor 1254) for 6 months. The cells of the tissue...

R. D. Kimbrough

1973-01-01

214

MR acoustic radiation force imaging: In vivo comparison to ultrasound motion tracking  

PubMed Central

MR acoustic radiation force (ARF) imaging was developed for measuring tissue elastic properties using focused ultrasound to deliver a localized tissue motion. In this study, an imaging ultrasound transducer was mounted on the focused ultrasound transducer and ultrasound motion tracking was performed simultaneously to MR ARF imaging to validate the measurement results. In vivo studies on rabbit thigh muscle were performed and results showed a general agreement between the two modalities (slope=0.96 and R2=0.67). The temporal information by the ultrasound measurement indicates that the parameters in MR ARF imaging should be optimized according to the tissue type, acoustic power, and envelope and frequency of the ARF modulation.

Huang, Yuexi; Curiel, Laura; Kukic, Aleksandra; Plewes, Donald B.; Chopra, Rajiv; Hynynen, Kullervo

2009-01-01

215

Robotic 5-dimensional ultrasound  

US Patent & Trademark Office Database

A robotic 5D ultrasound system and method, for use in a computer integrated surgical system, wherein 3D ultrasonic image data is integrated over time with strain (i.e., elasticity) image data. By integrating the ultrasound image data and the strain image data, the present invention is capable of accurately identifying a target tissue in surrounding tissue; segmenting, monitoring and tracking the target tissue during the surgical procedure; and facilitating proper planning and execution of the surgical procedure, even where the surgical environment is noisy and the target tissue is isoechoic.

Boctor; Emad M. (Baltimore, MD); Choti; Michael (Glen Arm, MD); Fichtinger; Gabor (Bethesda, MD); Taylor; Russell (Severna Park, MD); Prince; Jerry L. (Lutherville, MD)

2011-03-08

216

Quantification of petroleum-type hydrocarbons in avian tissue  

USGS Publications Warehouse

Summary: Methods were developed for the analysis of 16 hydrocarbons in avian tissue. Mechanical extraction with pentane was followed by clean-up on Florisil and Silicar. Residues were determined by gas--liquid chromatography and gas-liquid, chromatography-mass spectrometry. The method was applied to the analysis of liver, kidney, fat, and brain tissue of mallard ducks (Anas platyrhynchos) fed a mixture of hydrocarbons. Measurable concentrations of all compounds analyzed were present in all tissues except brain. Highest concentrations were in fat.

Gay, M.L.; Belisle, A.A.; Patton, J.F.

1980-01-01

217

Advances in ultrasound.  

PubMed

Ultrasound (US) has undergone dramatic changes since its inception three decades ago; the original cumbersome B-mode gantry system has evolved into a high resolution real-time imaging system. This review describes both recent advances in ultrasound and contrast media and likely future developments. Technological advances in electronics and computing have revolutionized ultrasound practice with ever expanding applications. Developments in transducer materials and array designs have resulted in greater bandwidths with improvements in spatial and contrast resolution. Developments in digital signal processing have produced innovations in beam forming, image display and archiving. Technological advances have resulted in novel imaging modes which exploit the non-linear behaviour of tissue and microbubble contrast agents. Microbubble contrast agents have dramatically extended the clinical and research applications of ultrasound. Not only can Doppler studies be enhanced but also novel non-linear modes allow vessels down to the level of the microcirculation to be imaged. Functional and quantitative studies allow interrogation of a wide spectrum of tissue beds. The advent of tissue-specific agents promises to improve the sensitivity and specificity of ultrasound in the detection and characterization of focal liver lesions to rival that of computed tomography (CT) and magnetic resonance imaging (MRI). Ultrasound has recently moved into therapeutic applications with high intensity focused ultrasound (HIFU) and microbubble assisted delivery of drugs and genes showing great promise. PMID:11952309

Harvey, Christopher J; Pilcher, James M; Eckersley, Robert J; Blomley, Martin J K; Cosgrove, David O

2002-03-01

218

Tissue distribution of the antigenic variants of canine parvovirus type 2 in dogs  

Microsoft Academic Search

Twelve dogs dead as consequence of natural infection caused by canine parvovirus (CPV) type 2a (n=4), type 2b (n=4) or type 2c (n=4) were investigated for determining the viral DNA loads in different tissue samples. By means of a real-time PCR assay, CPV DNA was detected in all tissues examined, with the highest titres observed in the lymphoid tissue and

Nicola Decaro; Vito Martella; Gabriella Elia; Costantina Desario; Marco Campolo; Eleonora Lorusso; Maria Loredana Colaianni; Alessio Lorusso; Canio Buonavoglia

2007-01-01

219

Intrathyroid salivary gland-type tissue in multinodular goiter  

Microsoft Academic Search

We report a case of intrathyroid salivary gland tissue in a 66-year-old Caucasian female with multinodular goiter. Lobules of well differentiated seromucinous salivary glands were found in close relationship with cartilage and fat, and intimately associated with normal thyroid follicles and solid cell nests (SCN) of the thyroid gland. This is the first report of non-neoplastic intrathyroid salivary gland tissue.

J. Cameselle-Teijeiro; J. Varela-Durán

1994-01-01

220

Automated classification of tissue by type using real-time spectroscopy  

NASA Astrophysics Data System (ADS)

Each tissue type has a unique spectral signature (e.g. liver looks distinct from bowel due to differences in both absorbance and in the way the tissue scatters light). While differentiation between normal tissues and tumors is not trivial, automated discrimination among normal tissue types (e.g. nerve, artery, vein, muscle) is feasible and clinically important, as many medical errors in medicine involve the misidentification of normal tissues. In this study, we have found that spectroscopic differentiation of tissues can be successfully applied to tissue samples (kidney and uterus) and model systems (fruit). Such optical techniques may usher in use of optical tissue diagnosis, leading to automated and portable diagnostic devices which can identify tissues, and guide use of medical instruments, such as during ablation or biopsy.

Benaron, David A.; Cheong, Wai-Fung; Duckworth, Joshua L.; Noles, Kenneth; Nezhat, Camran; Seidman, Daniel; Hintz, Susan R.; Levinson, Carl J.; Murphy, Aileen L.; Price, John W.; Liu, Frank W.; Stevenson, David K.; Kermit, Eben L.

1997-12-01

221

Correspondence Analysis of Genes and Tissue Types and Finding Genetic Links from Microarray Data  

Microsoft Academic Search

In this paper, we propose and use two novel procedures for the analysis of microarray gene expression data. The first is correspondence analysis which visualizes the relationship between genes and tissues as two 2 dimensional graphs, oriented so that distances between genes are preserved, distances between tissues are preserved, and so that genes which primarily distinguish certain types of tissue

Hirohisa Kishino; Peter J. Waddell

2000-01-01

222

Prioritization of compressed data by tissue type using JPEG2000  

NASA Astrophysics Data System (ADS)

One of the goals of telemedicine is to enable remote visualization and browsing of medical volumes. Volume data is usually massive and is compressed so as to effectively utilize available network bandwidth. In our scenario, these compressed datasets are stored on a central data server and are transferred progressively to one or more clients over a network. In this paper, we study schemes that enable progressive delivery for visualization of medical volume data using JPEG2000. We then present a scheme for progressive encoding based on scene content, that enables a progression based on tissues or regions of interest in 3D medical imagery. The resulting compressed file is organized such that the tissues of interest appear in earlier segments of the bitstream. Hence a compliant decoder that chooses to stop transmission of data at a given instant would be able to render the tissue of interest with a better visual quality.

Krishnan, Karthik; Marcellin, Michael W.; Bilgin, Ali; Nadar, Mariappan

2005-04-01

223

Ultrasound-induced enhancement of ACh, AChE and GABA in fetal brain tissue of mouse.  

PubMed

Pregnant mice were exposed to continuous-wave (CW) ultrasound of 875 kHz frequency at 1 W/cm2 for 300 and 400 s, spread over five days, starting from the sixth day of pregnancy. The neurotransmitters, acetylcholine (ACh) and gamma amino butyric acid (GABA), and the associated enzyme acetylcholinesterase (AChE) levels, were estimated in the exposed fetal brains. Enhanced levels, significant at p < 0.001, were observed in the brains excised on day 10, day 15 and day 20 of gestation compared to sham-exposed and cage-control brains. PMID:8356785

Suneetha, N; Kumar, R P

1993-01-01

224

Tendon structure changes after maximal exercise in the Thoroughbred horse: use of ultrasound tissue characterisation to detect in vivo tendon response.  

PubMed

Investigations into the response of the superficial digital flexor tendon (SDFT) of the Thoroughbred horse to mechanical stimuli have been limited to in vitro cell culture studies focused primarily on gene expression of critical matrix proteins. It is uncertain how well in vitro outcomes translate to the tendon of the horse during exercise. The current study examined changes in tendon structure in response to maximal exercise using ultrasound tissue characterisation (UTC) to scan the SDFT prior to and after competitive racing. UTC uses contiguous transverse ultrasound images to assess the dynamics of the echopattern, which has a close relationship with changes in the 3-D ultra-structure of the tendon. Using UTC, it was possible to detect subtle changes in the dynamics of the echopattern, with a reduction in pixels that represent aligned and integer collagen tendon bundles on days 1 and 2 post-race when compared to pre-race (P<0.05). The echopattern of these tendons returned to baseline on day 3. This change in echopattern was not seen in control horses. It was concluded that short-term changes in the SDFT following maximal exercise could be detected using UTC. PMID:22658820

Docking, S I; Daffy, J; van Schie, H T M; Cook, J L

2012-06-01

225

Ultrasound--biophysics mechanisms†  

PubMed Central

Ultrasonic biophysics is the study of mechanisms responsible for how ultrasound and biological materials interact. Ultrasound-induced bioeffect or risk studies focus on issues related to the effects of ultrasound on biological materials. On the other hand, when biological materials affect the ultrasonic wave, this can be viewed as the basis for diagnostic ultrasound. Thus, an understanding of the interaction of ultrasound with tissue provides the scientific basis for image production and risk assessment. Relative to the bioeffect or risk studies, that is, the biophysical mechanisms by which ultrasound affects biological materials, ultrasound-induced bioeffects are generally separated into thermal and nonthermal mechanisms. Ultrasonic dosimetry is concerned with the quantitative determination of ultrasonic energy interaction with biological materials. Whenever ultrasonic energy is propagated into an attenuating material such as tissue, the amplitude of the wave decreases with distance. This attenuation is due to either absorption or scattering. Absorption is a mechanism that represents that portion of ultrasonic wave that is converted into heat, and scattering can be thought of as that portion of the wave, which changes direction. Because the medium can absorb energy to produce heat, a temperature rise may occur as long as the rate of heat production is greater than the rate of heat removal. Current interest with thermally mediated ultrasound-induced bioeffects has focused on the thermal isoeffect concept. The non-thermal mechanism that has received the most attention is acoustically generated cavitation wherein ultrasonic energy by cavitation bubbles is concentrated. Acoustic cavitation, in a broad sense, refers to ultrasonically induced bubble activity occurring in a biological material that contains pre-existing gaseous inclusions. Cavitation-related mechanisms include radiation force, microstreaming, shock waves, free radicals, microjets and strain. It is more challenging to deduce the causes of mechanical effects in tissues that do not contain gas bodies. These ultrasonic biophysics mechanisms will be discussed in the context of diagnostic ultrasound exposure risk concerns.

O'Brien, William D.

2007-01-01

226

Facial soft tissue thickness in skeletal type I Japanese children  

Microsoft Academic Search

Facial reconstruction techniques used in forensic anthropology require knowledge of the facial soft tissue thickness of each race if facial features are to be reconstructed correctly. If this is inaccurate, so also will be the reconstructed face. Knowledge of differences by age and sex are also required. Therefore, when unknown human skeletal remains are found, the forensic anthropologist investigates for

Hajime Utsuno; Toru Kageyama; Toshio Deguchi; Yasunobu Umemura; Mineo Yoshino; Hiroshi Nakamura; Hiroo Miyazawa; Katsuhiro Inoue

2007-01-01

227

Quantitative evaluation of viable tissue perfusion changes with contrast-enhanced greyscale ultrasound in a mouse hepatoma model following treatment with different doses of thalidomide  

PubMed Central

Objective This study aimed to quantify intratumoural viable tissue perfusion with contrast-enhanced greyscale ultrasound to evaluate tumour response to anti-angiogenic treatment. Methods H22 hepatoma-bearing mice were treated with low-dose thalidomide (Group B), high-dose thalidomide (Group C) or 0.5% carboxylmethylcellulose (Group A). Contrast-enhanced greyscale ultrasound was performed after 7 days of treatments to evaluate the percentage of non-enhanced area for each tumour; regions of interest within the enhanced area were analysed offline to determine the area under the curve (AUC), maximum intensity (IMAX), perfusion index (PI), mean transit time (MTT), time to peak (TTP) and quality of fit (QOF). Immunohistochemical analysis was performed for evaluation of microvascular density (MVD). Results The percentage of non-enhanced area was significantly larger in Group C than in Groups A and B (p<0.05); however, there was no significant difference between Groups A and B. Treatment with thalidomide resulted in a significant decrease in AUC, PI and IMAX compared with Group A (p<0.05). Immunohistochemistry showed significant decreases in MVD in Groups B and C compared with Group A (p<0.05); however, there was no significant difference in MVD between Groups B and C. MVD was positively correlated with IMAX (r = 0.419, p = 0.023) and PI (r = 0.455, p = 0.013). Conclusion Quantitatively analysing intratumoural viable tissue perfusion enables early evaluation of tumour response to anti-angiogenic therapy before apparent changes in tumour necrosis.

Zhou, J H; Zheng, W; Cao, L H; Liu, M; Luo, R Z; Han, F; Wu, P H; Li, A H

2011-01-01

228

Topographical control of ocular cell types for tissue engineering.  

PubMed

Visual impairment affects over 285 million people worldwide and has a major impact on an individual's quality of life. Tissue engineering has the potential to increase the quality of life for many of these patients by preventing vision loss or restoring vision using cell-based therapies. However, these strategies will require an understanding of the microenvironmental factors that influence cell behavior. The eye is a well-organized organ whose structural complexity is essential for proper function. Interactions between ocular cells and their highly ordered extracellular matrix are necessary for maintaining key tissue properties including corneal transparency and retinal lamination. Therefore, it is not surprising that culturing these cells in vitro on traditional flat substrates result in irregular morphology. Instead, topographically patterned biomaterials better mimic native extracellular matrix and have been shown to elicit in vivo-like morphology and gene expression which is essential for tissue engineering. Herein we review multiple methods for producing well-controlled topography and discuss optimal biomaterial scaffold design for cells of the cornea, retina, and lens. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013. PMID:23744715

McHugh, Kevin J; Saint-Geniez, Magali; Tao, Sarah L

2013-06-01

229

Use of a continuous external tissue expander in the conversion of a type IIIB fracture to a type IIIA fracture.  

PubMed

Various methods have been used for soft tissue coverage of Gustilo-Anderson type IIIB open fractures. These injuries are often contaminated and, by definition, are associated with extensive periosteal stripping and inadequate soft tissue coverage. These characteristics predispose the patient to infection, delayed union, nonunion, and the likelihood of multiple surgeries to achieve durable soft tissue coverage. Although free tissue transfer and rotational flap coverage are the mainstay of treatment for Gustilo-Anderson type IIIB fractures, these procedures typically require additional modalities, such as local wound care, negative-pressure wound therapy, and skin grafting, to expedite wound coverage. Numerous undesirable aspects of these tissue coverage techniques exist, including the requirement for repeated application, potential anesthesia complications, near-constant surveillance, patient compliance, graft failure, and cost. External tissue expanders offer the surgeon a device that can rapidly facilitate closure of full-thickness soft tissue defects. This technique offers the benefit of a 1-time application that is easy to apply and cost-effective and can significantly improve fracture coverage options with a cosmetically acceptable result. Although this technique has been previously described for fasciotomy and ulcer coverage, to the authors' knowledge, continuous external expansion has never been reported in open fracture wound management, specifically in converting type IIIB to type IIIA open fractures. The authors' early success with this method indicates that it may be a valuable tool in the management of Gustilo-Anderson type IIIB open fractures. PMID:23383680

Formby, Peter; Flint, James; Gordon, Wade T; Fleming, Mark; Andersen, Romney C

2013-02-01

230

Validation of tissue change monitoring (TCM) on the Sonablate® 500 during high intensity focused ultrasound (HIFU) treatment of prostate cancer with real-time thermometry  

NASA Astrophysics Data System (ADS)

The Sonablate® 500 has quantitative, real-time Tissue Change Monitoring (TCM) software that estimates changes in tissue properties due to HIFU treatment of prostate cancer. This study validates the Sonablate 500 TCM system using real-time thermometry. Five patients with histologically confirmed, organ-confined prostate cancer were enrolled. Four patients with focal cancer had hemiablation and one had whole gland ablation. TCM generates energy reading based on spectral analysis on the RF backscattered ultrasound signals; results are used as an estimator of tissue temperature. Needle thermocouples were placed transperineally under TRUS guidance in the prostate to monitor temperatures from focal zone, posterior to the focal zone and on the lateral gland where no HIFU was applied. The HIFU treatments averaged 37, 35 and 19.7 Watts for the treatment for anterior, middle and posterior zones. The measured temperatures (Average, Max, and Min) in the HIFU treatment zones were 84, 114 and 70 degrees C. The temperature estimated by TCM energy readings were 83% 75-100 degrees C and 17% 60-75 degrees C with an average of 91 degrees C. Outside the focal zone, average recorded temperature was 50 degrees C. Average temperature in the lateral lobe where no HIFU was applied was 40.7 degrees C.

Chen, Wo-Hsing; Sanghvi, Narendra T.; Carlson, Roy; Schatzl, Georg; Marberger, Michael

2012-10-01

231

Current time-domain methods for assessing tissue motion by analysis from reflected ultrasound echoes-a review  

Microsoft Academic Search

The Doppler technique has traditionally been the method used to extract motion information from ultrasonic echoes reflected by moving tissues. The Doppler technique has been around for a long time, and has been extensively reviewed and analyzed in the literature. Recently, time-domain methodologies for estimating tissue motion have gained in popularity. Time-domain methods have advantages over Doppler methods in many

I. A. Hein

1993-01-01

232

Intrathyroidal branchial cleft-like cyst with heterotopic salivary gland-type tissue.  

PubMed

A rare case is described of intrathyroidal branchial cleft-like cyst associated with unusual heterotopic tissues including the salivary gland type tissue, fat, and cartilage. This coexistence in the thyroid gland has not been described previously, to our knowledge. The patient was a 7-year-old girl with a growing mass in the left lateral neck. The ultrasonography revealed a cystic lesion in the left thyroid. Histologically, the cyst was lined by squamous or respiratory-type epithelium resting on the fibrous tissue containing lymphoid tissues with follicle formation and solid cell nests (SCNs). This cyst was intimately associated with heterotopic tissues including lobules of well-differentiated seromucinous salivary glands, mature fat tissue, and islands of the cartilage. This association of branchial cleft-like cyst with SCNs and unusual heterotopic tissues in the normal thyroid suggests a possible origin from the SCN as ultimobranchial vestigial structures. PMID:15037945

Park, Ji-Young; Kim, Gou Young; Suh, Yeon-Lim

2004-03-25

233

Section-thickness profiling for brachytherapy ultrasound guidance  

Microsoft Academic Search

Purpose: Ultrasound (US) elevation beamwidth causes a certain type of image artifact around the anechoic areas of the tissue. It is generally assumed that the US image is of zero thickness, which contradicts the fact that the acoustic beam can only be mechanically focused at a depth resulting in a finite, non-uniformed elevation beamwidth. We suspect that elevation beamwidth artifacts

Mohammad Peikari; Thomas K. Chen; Everette C. Burdette; Gabor Fichtinger

2011-01-01

234

Stable isotopes and elasmobranchs: tissue types, methods, applications and assumptions.  

PubMed

Stable-isotope analysis (SIA) can act as a powerful ecological tracer with which to examine diet, trophic position and movement, as well as more complex questions pertaining to community dynamics and feeding strategies or behaviour among aquatic organisms. With major advances in the understanding of the methodological approaches and assumptions of SIA through dedicated experimental work in the broader literature coupled with the inherent difficulty of studying typically large, highly mobile marine predators, SIA is increasingly being used to investigate the ecology of elasmobranchs (sharks, skates and rays). Here, the current state of SIA in elasmobranchs is reviewed, focusing on available tissues for analysis, methodological issues relating to the effects of lipid extraction and urea, the experimental dynamics of isotopic incorporation, diet-tissue discrimination factors, estimating trophic position, diet and mixing models and individual specialization and niche-width analyses. These areas are discussed in terms of assumptions made when applying SIA to the study of elasmobranch ecology and the requirement that investigators standardize analytical approaches. Recommendations are made for future SIA experimental work that would improve understanding of stable-isotope dynamics and advance their application in the study of sharks, skates and rays. PMID:22497393

Hussey, N E; MacNeil, M A; Olin, J A; McMeans, B C; Kinney, M J; Chapman, D D; Fisk, A T

2012-03-19

235

Activation of Adenovirus Type 5 Latent Infections of Tissue Culture  

Microsoft Academic Search

Summary To study the in vitro activation of latent adenovirus type 5 infection and enhancement of virus production, primary human amnion and HEp-2 cell cultures were inoculated with low doses of virus and subsequently treated with steroid hormones, carcinogens, or a pyrogen drug ‘Pyrago’ containing killed cells of bacteria and fungi. Immunofluorescence and CPE revealed that only pyrogen induced conversion

József Ongrádi; Gizella Kulcsár; Pál Dán; István Nász; József Horváth

1980-01-01

236

Prenatal Cardiac Ultrasound Finding in Congenital Disorder of Glycosylation Type 1a  

Microsoft Academic Search

We present the antenatal cardiac findings in an infant in whom a postnatal diagnosis of congenital disorder of glycosylation type Ia (CDG-Ia) was confirmed. The antenatal findings at 34 weeks’ gestation included biventricular cardiac hypertrophy with pericardial effusion, multiple skeletal anomalies and cerebral ventricular dilatation. A severe CDG-Ia multisystem clinical phenotype evolved in the postnatal period, with the infant succumbing

A. Malhotra; A. Pateman; R. Chalmers; D. Coman; S. Menahem

2009-01-01

237

Superresolution Ultrasound.  

National Technical Information Service (NTIS)

A computer program product resides on a computer-readable medium and comprises computer-readable, computer-executable instructions for causing a computer to transmit first indicia for an ultrasound propagation arrangement to propagate ultrasound energy to...

G. T. Clement K. H. Hynynen

2004-01-01

238

Ultrasound - Breast  

MedlinePLUS

... characterize potential abnormalities seen on mammography or breast magnetic resonance imaging (MRI). Ultrasound imaging can help to ... mammography. Many studies have shown that ultrasound and magnetic resonance imaging (MRI) can help supplement mammography by ...

239

In vivo characterization of tissue thermal properties of the kidney during local hyperthermia induced by MR-guided high-intensity focused ultrasound.  

PubMed

The purpose of this study was to evaluate quantitatively in vivo the tissue thermal properties during high-intensity focused ultrasound (HIFU) heating. For this purpose, a total of 52 localized sonications were performed in the kidneys of six pigs with HIFU monitored in real time by volumetric MR thermometry. The kidney perfusion was modified by modulation of the flow in the aorta by insertion of an inflatable angioplasty balloon. The resulting temperature data were analyzed using the bio-heat transfer model in order to validate the model under in vivo conditions and to estimate quantitatively the absorption (?), thermal diffusivity (D) and perfusion (w(b)) of renal tissue. An excellent correspondence was observed between the bio-heat transfer model and the experimental data. The absorption and thermal diffusivity were independent of the flow, with mean values (± standard deviation) of 20.7 ± 5.1 mm(3) K J(-1) and 0.23 ± 0.11 mm(2) s(-1), respectively, whereas the perfusion decreased significantly by 84% (p < 0.01) with arterial flow (mean values of w(b) of 0.06 ± 0.02 and 0.008 ± 0.007 mL(-1) mL s(-1)), as predicted by the model. The quantitative analysis of the volumetric temperature distribution during nondestructive HIFU sonication allows the determination of the thermal parameters, and may therefore improve the quality of the planning of noninvasive therapy with MR-guided HIFU. PMID:21834004

Cornelis, François; Grenier, Nicolas; Moonen, Chrit T; Quesson, Bruno

2010-12-12

240

Adaptive Thermal Therapy using Planar Ultrasound Transducers with Real-time MR Temperature Feedback: Demonstration in Gel Phantoms and Ex-vivo Tissues  

NASA Astrophysics Data System (ADS)

MRI-guided transurethral ultrasound therapy offers a minimally invasive approach for the treatment of localized prostate cancer. The main goal of this study was to evaluate active temperature feedback on a clinical 1.5T MR imager to control conformal thermal therapy. MR thermometry was performed during heating in both thermal gel phantoms and ex-vivo tissue with a single-element transurethral heating applicator. The applicator rotation rate and power were controlled based on MRI-temperature measurements. The influence of a cooling gradient (to simulate cooling of the rectum or urethra) was also investigated in gel phantoms. The 55°C isotherm generated during heating closely matched the targeted prostate shape, with an average distance error of 0.9 mm +/- 0.4 mm in turkey breasts, 1.3 mm +/- 0.5 mm in gel phantoms without rectal cooling and 1.4 mm +/- 0.6 mm in gel phantoms with rectal cooling. Accurate, MRI-guided, active feedback has been successfully demonstrated experimentally and has the capability to adjust for unpredictable and varying tissue properties during the treatment.

Tang, Kee; Choy, Vanessa; Chopra, Rajiv; Bronskill, Michael

2007-05-01

241

Technical Advances in Endoscopic Ultrasound (EUS)-Guided Tissue Acquisition for Pancreatic Cancers: How Can We Get the Best Results with EUS-Guided Fine Needle Aspiration?  

PubMed Central

Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is one of the least invasive and most effective modality in diagnosing pancreatic adenocarcinoma in solid pancreatic lesions, with a higher diagnostic accuracy than cystic tumors. EUS-FNA has been shown to detect tumors less than 3 mm, due to high spatial resolution allowing the detection of very small lesions and vascular invasion, particularly in the pancreatic head and neck, which may not be detected on transverse computed tomography. Furthermore, this minimally invasive procedure is often ideal in the endoscopic procurement of tissue in patients with unresectable tumors. While EUS-FNA has been increasingly used as a diagnostic tool, most studies have collectively looked at all primary pancreatic solid lesions, including lymphomas and pancreatic neuroendocrine neoplasms, whereas very few studies have examined the diagnostic utility of EUS-FNA of pancreatic ductal carcinoma only. As with any novel and advanced endoscopic procedure that may incorporate several practices and approaches, endoscopists have adopted diverse techniques to improve the tissue procurement practice and increase diagnostic accuracy. In this article, we present a review of literature to date and discuss currently practiced EUS-FNA technique, including indications, technical details, equipment, patient selection, and diagnostic accuracy.

Kedia, Prashant; Gaidhane, Monica

2013-01-01

242

Tissue engineering: using collagen type I matrix for bone healing of bone defects.  

PubMed

Among the many tissues in the human body, bone has been considered as a powerful marker for regeneration and its formation serves as a prototype model for tissue engineering based on morphogenesis. Therefore, collagen type I is one of the most useful biomaterials used in tissue engineering as extracellular matrix components capable to promote bone healing. The literature reveals excellent biocompatibility and safety due to its biological characteristics, such as biodegradability and weak antigenicity, making collagen type I the primary resource in medical applications. Thus, it was also used for tissue engineering including skin replacement, bone substitutes, and artificial blood vessels and valves. The authors describe the treatment of an abscessed apical periodontal cyst and show good outcomes of bone healing, using tissue engineering, as collagen type I matrix. PMID:23851732

Oliveira, Marina Reis; Martins, Elisa das Graças; Célio-Mariano, Ronaldo; Sonoda, Celso Koogi; Rangel Garcia, Idelmo; de Melo, Willian Morais

2013-07-01

243

Ultrasound (Sonography)  

NSDL National Science Digital Library

The Radiological Society of North America (RSNA) and the American College of Radiology (ACR) produce this website which provides information on 15 varieties of sonography including hysterosonography, obstetric ultrasound, and thyroid ultrasound. Sections on each variety of ultrasound provide information on common uses of the procedure, equipment, procedure results & interpretation, benefits and risks, and limitations. This is a great resource for instructors of courses related to diagnostic medical sonography and for the aspiring sonographer or ultrasound technician.

2007-04-30

244

Tissue type is a major modifier of the 5-hydroxymethylcytosine content of human genes  

PubMed Central

The discovery of substantial amounts of 5-hydroxymethylcytosine (5hmC), formed by the oxidation of 5-methylcytosine (5mC), in various mouse tissues and human embryonic stem (ES) cells has necessitated a reevaluation of our knowledge of 5mC/5hmC patterns and functions in mammalian cells. Here, we investigate the tissue specificity of both the global levels and locus-specific distribution of 5hmC in several human tissues and cell lines. We find that global 5hmC content of normal human tissues is highly variable, does not correlate with global 5mC content, and decreases rapidly as cells from normal tissue adapt to cell culture. Using tiling microarrays to map 5hmC levels in DNA from normal human tissues, we find that 5hmC patterns are tissue specific; unsupervised hierarchical clustering based solely on 5hmC patterns groups independent biological samples by tissue type. Moreover, in agreement with previous studies, we find 5hmC associated primarily, but not exclusively, with the body of transcribed genes, and that within these genes 5hmC levels are positively correlated with transcription levels. However, using quantitative 5hmC-qPCR, we find that the absolute levels of 5hmC for any given gene are primarily determined by tissue type, gene expression having a secondary influence on 5hmC levels. That is, a gene transcribed at a similar level in several different tissues may have vastly different levels of 5hmC (>20-fold) dependent on tissue type. Our findings highlight tissue type as a major modifier of 5hmC levels in expressed genes and emphasize the importance of using quantitative analyses in the study of 5hmC levels.

Nestor, Colm E.; Ottaviano, Raffaele; Reddington, James; Sproul, Duncan; Reinhardt, Diana; Dunican, Donncha; Katz, Elad; Dixon, J. Michael; Harrison, David J.; Meehan, Richard R.

2012-01-01

245

One-pot three-component Mannich-type reactions using Sulfamic acid catalyst under ultrasound irradiation  

Microsoft Academic Search

Sulfamic acid (NH2SO3H, SA) was used as an efficient, inexpensive, non-toxic and recyclable green catalyst for the ultrasound-assisted one-pot Mannich reaction of aldehydes with ketones and amines. This ultrasound protocol has advantages of high yield, mild condition, no environmental pollution, and simple work-up procedures. Most importantly, ?-aminocarbonyl compounds with ortho-substituted aromatic amines are obtained in acceptable to good yields by

Hongyao Zeng; Hua Li; Huawu Shao

2009-01-01

246

Cranial Ultrasound/Head Ultrasound  

MedlinePLUS

... Doppler (TCD) ultrasound evaluates both the direction and velocity of the blood flow in the major cerebral ... special application of ultrasound, measures the direction and speed of blood cells as they move through vessels. ...

247

The localization of the relaxed form of plasminogen activator inhibitor type 2 in human gingival tissues  

Microsoft Academic Search

The plasminogen activating system is important in extracellular proteolysis. Plasmin degrades tissues and activates proteases. Plasminogen activators (tissue type; t-PA and urokinase type; u-PA) and plasminogen activator inhibitors (PAI-1, PAI-2) are found in high concentrations in gingival crevicular fluid (GCF). Previous findings indicate the significance of PAI-2 in gingival inflammation. When PAI-2 inhibits a plasminogen activator its conformation relaxes and

Pia Lindberg; Mark S. Baker; Bertil Kinnby

2001-01-01

248

The diagnostic efficacy of combining bronchoscopic tissue biopsy and endobronchial ultrasound-guided transbronchial needle aspiration for the diagnosis of malignant lesions in the lung.  

PubMed

Bronchoscopic tissue forceps biopsy (BBX) is a standard procedure for diagnosis of malignancy in the lung. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has proven to be a sensitive alternative to tissue biopsy for the diagnosis and staging of lung tumors. We report our institutional experience with diagnostic yield when combining BBX and EBUS-TBNA in the bronchoscopic evaluation of patients presenting with lung lesion(s). The pathology files at our institution were searched for all patients who underwent combined BBX and EBUS-TBNA procedures between 1/09 and 6/10 for the diagnosis of malignancy. The data points included biopsy site, cytologic, and histopathologic diagnoses and follow-up. We identified 115 patients who underwent BBX combined with EBUS-TBNA. About 107 (93%) of the patients received a definitive pathologic diagnosis; 93 (81%) were malignant. BBX and EBUS-TBNA of the lung lesion only were performed in 21 patients, BBX and EBUS-TBNA of lymph node(s) only in 78 patients with BBX and a combination of EBUS-TBNA of the lung lesion and lymph node(s) in 16 patients. Immunostains were performed for 71 (76%) patients and molecular testing for 11 (12%) patients. Diagnostic yield is increased when bronchoscopic technologies are combined. In a significant number of patients where BBX was negative, EBUS-TBNA provided diagnostic material, increasing diagnostic yield by 18%. In a subset of these patients the EBUS-TBNA assisted in the staging of a primary tumor. By combining these procedures, more tissue was obtained for immunohistochemistry and molecular testing, which facilitated personalized management in a minimally invasive manner. Diagn. Cytopathol. 2013;41:929-935. © 2012 Wiley Periodicals, Inc. PMID:22362678

Schwartz, Lauren Ende; Aisner, Dara L; Baloch, Zubair W; Sterman, Daniel; Vachani, Anil; Gillespie, Colin; Haas, Andrew; Litzky, Leslie A

2012-02-23

249

Ultrasound at 27 kHz increases tissue expression and activity of nitric oxide synthases in acute limb ischemia in rabbits.  

PubMed

Transcutaneous low-frequency ultrasound (US) preserves myocardial and skeletal muscle viability by increasing tissue perfusion through an undefined nitric oxide (NO)-dependent mechanism. We have examined whether US increases tissue expression and activity of the three nitric oxide synthase (NOS) isoforms: endothelial (eNOS), neuronal (nNOS) and inducible (iNOS). The two femoral arteries of four New Zealand rabbits were ligated for a total of 120 min. After 60 min of ligation, transcutaneous low-frequency US (27 kHz, 0.13 W/cm2) was applied for 60 min to one thigh, while the contra-lateral artery served as a control (total ischemia time=120 min). Calcium-dependent (cNOS) and -independent (ciNOS) NOS activity, and concentration of total eNOS, ser-1177 phosphorylated eNOS (P-eNOS), nNOS and iNOS were then determined in the gracilis muscle. Compared with the control, US application significantly increased cNOS activity [3.34+/-0.28 versus 3.87+/-0.10x1000 counts per minute (cpm), respectively, p=0.031] and ciNOS activity (1.99+/-0.09 versus 3.26+/-0.68 cpm, respectively, p<0.001). Western immunoblotting revealed a significant increase in protein content of both iNOS (184.5+/-1.08%; p<0.0001) and P-eNOS (381.5+/-2.47%; p<0.001), with only a small increase in total eNOS and nNOS expression. In conclusion, application of transcutaneous low-frequency US to ischemic muscular tissue significantly increases both cNOS and ciNOS activity by increasing eNOS phosphorylation and iNOS expression, respectively. PMID:17507145

Atar, Shaul; Siegel, Robert J; Akel, Rami; Ye, Yumei; Lin, Yu; Modi, Shreyas A; Sewani, Asif; Tuero, Enrique; Birnbaum, Yochai

2007-05-16

250

Cell-Type-Specific Genome-wide Expression Profiling after Laser Capture Microdissection of Living Tissue  

SciTech Connect

The purpose of this technical feasibility study was to develop and evaluate robust microgenomic tools for investigations of genome-wide expression of very small numbers of cells isolated from whole tissue sections. Tissues contain large numbers of cell-types that play varied roles in organ function and responses to endogenous and exogenous toxicants whether bacterial, viral, chemical or radiation. Expression studies of whole tissue biopsy are severely limited because heterogeneous cell-types result in an averaging of molecular signals masking subtle but important changes in gene expression in any one cell type(s) or group of cells. Accurate gene expression analysis requires the study of specific cell types in their tissue environment but without contamination from surrounding cells. Laser capture microdissection (LCM) is a new technology to isolate morphologically distinct cells from tissue sections. Alternative methods are available for isolating single cells but not yet for their reliable genome-wide expression analyses. The tasks of this feasibility project were to: (1) Develop efficient protocols for laser capture microdissection of cells from tissues identified by antibody label, or morphological stain. (2) Develop reproducible gene-transcript analyses techniques for single cell-types and determine the numbers of cells needed for reliable genome-wide analyses. (3) Validate the technology for epithelial and endothelial cells isolated from the gastrointestinal tract of mice.

Marchetti, F; Manohar, C F

2005-02-09

251

21 CFR 1271.85 - What donor testing is required for different types of cells and tissues?  

Code of Federal Regulations, 2010 CFR

...testing is required for different types of cells and tissues? 1271.85 Section 1271...THE FOOD AND DRUG ADMINISTRATION HUMAN CELLS, TISSUES, AND CELLULAR AND TISSUE-BASED...testing is required for different types of cells and tissues? (a) All donors...

2009-04-01

252

21 CFR 1271.85 - What donor testing is required for different types of cells and tissues?  

Code of Federal Regulations, 2010 CFR

...testing is required for different types of cells and tissues? 1271.85 Section 1271...THE FOOD AND DRUG ADMINISTRATION HUMAN CELLS, TISSUES, AND CELLULAR AND TISSUE-BASED...testing is required for different types of cells and tissues? (a) All donors...

2010-04-01

253

21 CFR 1271.85 - What donor testing is required for different types of cells and tissues?  

Code of Federal Regulations, 2010 CFR

...testing is required for different types of cells and tissues? 1271.85 Section 1271...THE FOOD AND DRUG ADMINISTRATION HUMAN CELLS, TISSUES, AND CELLULAR AND TISSUE-BASED...testing is required for different types of cells and tissues? (a) All donors...

2012-04-01

254

Ultrasound-guided percutaneous delivery of tissue-engineered endothelial cells to the adventitia of stented arteries controls the response to vascular injury in a porcine model  

PubMed Central

Objective High restenosis rates are a limitation of peripheral vascular interventions. Previous studies have shown that surgical implantation of a tissue-engineered endothelium onto the adventitia surface of injured vessels regulates vascular repair. In the present study, we developed a particulate formulation of tissue-engineered endothelium and a method to deliver the formulation perivascular to injured blood vessels using a percutaneous, minimally invasive technique. Methods Stainless steel stents were implanted in 18 balloon-injured femoral arteries of nine domestic swine, followed by ultrasound-guided percutaneous perivascular injection of gelatin particles containing cultured allogeneic porcine aortic endothelial cells (PAE). Controls received injections of empty particles (matrix) or no perivascular injection (sham) after stent deployment. Animals were sacrificed after 90 days. Results Angiographic analysis revealed a significantly greater lumen diameter in the stented segments of arteries treated with PAE/matrix (4.72 ± 0.12 mm) compared with matrix (4.01 ± 0.20 mm) or sham (4.03 ± 0.16 mm) controls (P< .05). Similarly, histologic analysis revealed that PAE/matrix-treated arteries had the greatest lumen area(20.4 ± 0.7 mm2; P< .05) compared with controls (16.1 ± 0.9 mm2 and 17.1 ±1.0 mm2 for sham and matrix controls, respectively) and the smallest intimal area (3.3 ± 0.4 mm2; P < .05) compared with controls (6.2 ±0.5 mm2 and 4.4 ±0.5 mm2 for sham and matrix controls, respectively). Overall, PAE-treated arteries had a 33% to 50% decrease in percent occlusion (P < .05) compared with controls. Histopathological analysis revealed fewer leukocytes present in the intima in the PAE/matrix group compared with control groups, suggesting that the biological effects were in part due to inhibition of the inflammatory phase of the vascular response to injury. Conclusions Minimally invasive, perivascular delivery of PAE/matrix to stented arteries was performed safely using ultrasound-guided percutaneous injections and significantly decreased stenosis. Application at the time of or subsequent to peripheral interventions may decrease clinical restenosis rates.

Nugent, Helen M.; Ng, Yin-Shan; White, Desmond; Groothius, Adam; Kanner, Glenn; Edelman, Elazer R.

2013-01-01

255

Evaluation of ultrasound techniques for brain injury detection  

NASA Astrophysics Data System (ADS)

In this work, we examine the physics underlying wave propagation in the head to evaluate various ultrasonic transducers for use in a brian injury detection device. The results of measurements of the attenuation coefficient and phase velocity for ultrasonic propagation in samples of brain tissue and skull bone from sheep are presented. The material properties are then used to investigate the propagation of ultrasonic pressure fields in the head. The ultrasound fields for three different transducers are calculated for propagation in a simulated brain/skull model. The model is constructed using speed-of-sound and mass density values of the two tissue types. The impact of the attenuation on the ultrasound fields is then examined. Finally, the relevant points drawn from these discussions are summarized. We hope to minimize the confounding effects of the skull by using sub-MHz ultrasound while maintaining the necessary temporal and spatial resolution to successfully detect injury in the brain.

Mobley, Joel; Kasili, Paul M.; Norton, Stephen J.; Vo-Dinh, Tuan

1998-05-01

256

Conformal thermal therapy using planar ultrasound transducers and adaptive closed-loop MR temperature control: demonstration in gel phantoms and ex vivo tissues  

NASA Astrophysics Data System (ADS)

MRI-guided transurethral ultrasound therapy offers a minimally invasive approach for the treatment of localized prostate cancer. Integrating a multi-element planar transducer with active MR temperature feedback can enable three-dimensional conformal thermal therapy of a target region within the prostate gland while sparing surrounding normal tissues. Continuous measurement of the temperature distribution in tissue enables dynamic compensation for unknown changes in blood flow and tissue properties during treatment. The main goal of this study was to evaluate the feasibility of using active temperature feedback on a clinical 1.5 T MR imager for conformal thermal therapy. MR thermometry was performed during heating in both gel phantoms and excised tissue with a transurethral heating applicator, and the rotation rate and power were varied based on the thermal measurements. The capability to produce a region of thermal damage that matched a target boundary was evaluated. The influence of a cooling gradient (to simulate cooling of the rectum or urethra) on the desired pattern of thermal damage was also investigated in gel phantoms. Results showed high correlation between the desired target boundary and the 55 °C isotherm generated during heating with an average distance error of 0.9 mm ± 0.4 mm (n = 6) in turkey breasts, 1.4 mm ± 0.6 mm (n = 4) in gel phantoms without rectal cooling and 1.4 mm ± 0.6 mm (n = 3) in gel phantoms with rectal cooling. The results were obtained using a temporal update rate of 5 s, a spatial resolution of 3 × 3 × 10 mm for the control point, and a temperature uncertainty of approximately 1 °C. The performance of the control algorithm under these conditions was comparable to that of simulations conducted previously by our group. Overall, the feasibility of generating targeted regions of thermal damage with a transurethral heating applicator and active MR temperature feedback has been demonstrated experimentally. This method of treatment appears capable of accounting for unpredictable and varying tissue properties during the treatment.

Tang, K.; Choy, V.; Chopra, R.; Bronskill, M. J.

2007-05-01

257

Benign breast lesions: Ultrasound  

PubMed Central

Benign breast diseases constitute a heterogeneous group of lesions arising in the mammary epithelium or in other mammary tissues, and they may also be linked to vascular, inflammatory or traumatic pathologies. Most lesions found in women consulting a physician are benign. Ultrasound (US) diagnostic criteria indicating a benign lesion are described as well as US findings in the most frequent benign breast lesions.

Masciadri, N.; Ferranti, C.

2011-01-01

258

Comparative study of the topical application of Aloe vera gel, therapeutic ultrasound and phonophoresis on the tissue repair in collagenase-induced rat tendinitis.  

PubMed

The aim of our study was to compare topical use of Aloe vera gel, pulsed mode ultrasound (US) and Aloe vera phonophoresis on rat paw with collagenase-induced tendinitis. Edema size, tensile tendon strength, tendon elasticity, number of inflammatory cells and tissue histology were studied at 7 and 14 days after tendinitis induction. Pulse mode US parameters were: 1 MHz frequency, 100 Hz repetition rate, 10% duty cycle, and 0.5 W/cm(2) intensity, applied for 2 min each session. A 0.5 mL of Aloe vera gel at 2% concentration was applied for 2 min per session, topically and by phonophoresis. Topical application of Aloe vera gel did not show any statistically significant improvement in the inflammatory process, whereas phonophoresis enhanced the gel action reducing edema and number of inflammatory cells, promoting the rearrangement of collagen fibers and promoting also the recovery of the tensile strength and elasticity of the inflamed tendon to recover their normal pre-injury status. Results seem to indicate that Aloe vera phonophoresis is a promising technique for tendinitis treatment, without the adverse effect provoked by systemic anti-inflammatory drugs. PMID:20800944

Maia Filho, Antonio Luiz Martins; Villaverde, Antonio Balbin; Munin, Egberto; Aimbire, Flávio; Albertini, Regiane

2010-10-01

259

Pulse inversion chirp coded tissue harmonic imaging (PI-CTHI) of Zebrafish heart using high frame rate ultrasound biomicroscopy.  

PubMed

This paper reports a pulse inversion chirp coded tissue harmonic imaging (PI-CTHI) method for visualizing small animal hearts that provides fine spatial resolution at a high frame rate without sacrificing the echo signal to noise ratio (eSNR). A 40 MHz lithium niobate (LiNbO(3)) single element transducer is employed to evaluate the performance of PI-CTHI by scanning tungsten wire targets, spherical anechoic voids, and zebrafish hearts. The wire phantom results show that PI-CTHI improves the eSNR by 4 dB from that of conventional pulse inversion tissue harmonic imaging (PI-THI), while still maintaining a spatial resolution of 88 and 110 ?m in the axial and lateral directions, respectively. The range side lobe level of PI-CTHI is 11 dB lower than that of band-pass filtered CTHI (or F-CTHI). In the anechoic sphere phantom study, the contrast-to-noise ratio of PI-CTHI is found to be 2.7, indicating a 34% enhancement over conventional PI-THI. Due to such improved eSNR and contrast resolution, blood clots in zebrafish hearts can be readily visualized throughout heart regeneration after 20% of the ventricle is removed. Disappearance of the clots in the early stages of the regeneration has been observed for 7 days without sacrificing the fish. PMID:22930467

Park, Jinhyoung; Huang, Ying; Chen, Ruimin; Lee, Jungwoo; Cummins, Thomas M; Zhou, Qifa; Lien, Ching-Ling; Shung, K K

2012-08-29

260

Immunohistochemical localization of short chain cartilage collagen (type X) in avian tissues  

Microsoft Academic Search

Monoclonal antibodies were produced against the recently described short chain cartilage collagen (type X collagen), and one (AC9) was extensively characterized and used for immunohistochemical localization studies on chick tissues. By competition enzyme-linked immunosorbent assay, antibody AC9 was observed to bind to an epitope within the helical domain of type X collagen and did not react with the other collagen

THOMAS M. SCHMID; THOMAS F. LINSENMAYER

1985-01-01

261

Effective gene delivery with liposomal bubbles and ultrasound as novel non-viral system.  

PubMed

We developed the novel liposomal bubbles (Bubble liposomes) containing ultrasound imaging gas, perfluoropropane. Bubble liposomes were made of pegylated liposomes and were smaller than conventional microbubbles. Bubble liposomes also had a function as imaging agents in cardiosonography. In addition, Bubble liposomes could deliver plasmid DNA into various types of cells in vitro without cytotoxicity by the combination of ultrasound. In vivo gene delivery, Bubble liposomes could deliver plasmid DNA into mouse femoral artery by the transdermally exposure of ultrasound. This transfection efficiency was more effectively than lipofection method. Interestingly, the gene expression was only observed at the site of ultrasound exposure. Therefore, we concluded that Bubble liposomes could be good tools to establish tissue-specific gene delivery system as well as ultrasound imaging agents. PMID:17671899

Suzuki, Ryo; Takizawa, Tomoko; Negishi, Yoichi; Utoguchi, Naoki; Maruyama, Kazuo

262

AMUM LECTURE: Therapeutic ultrasound  

NASA Astrophysics Data System (ADS)

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

Crum, Lawrence A.

2004-01-01

263

Medical ultrasound systems  

PubMed Central

Medical ultrasound imaging has advanced dramatically since its introduction only a few decades ago. This paper provides a short historical background, and then briefly describes many of the system features and concepts required in a modern commercial ultrasound system. The topics addressed include array beam formation, steering and focusing; array and matrix transducers; echo image formation; tissue harmonic imaging; speckle reduction through frequency and spatial compounding, and image processing; tissue aberration; Doppler flow detection; and system architectures. It then describes some of the more practical aspects of ultrasound system design necessary to be taken into account for today's marketplace. It finally discusses the recent explosion of portable and handheld devices and their potential to expand the clinical footprint of ultrasound into regions of the world where medical care is practically non-existent. Throughout the article reference is made to ways in which ultrasound imaging has benefited from advances in the commercial electronics industry. It is meant to be an overview of the field as an introduction to other more detailed papers in this special issue.

Powers, Jeff; Kremkau, Frederick

2011-01-01

264

What is ultrasound?  

PubMed

This paper is based on material presented at the start of a Health Protection Agency meeting on ultrasound and infrasound. In answering the question 'what is ultrasound?', it shows that the simple description of a wave which transports mechanical energy through the local vibration of particles at frequencies of 20 kHz or more, with no net transport of the particles themselves, can in every respect be misleading or even incorrect. To explain the complexities responsible for this, the description of ultrasound is first built up from the fundamental properties of these local particle vibrations. This progresses through an exposition of the characteristics of linear waves, in order to explain the propensity for, and properties of, the nonlinear propagation which occurs in many practical ultrasonic fields. Given the Health Protection environment which framed the original presentation, explanation and examples are given of how these complexities affect issues of practical importance. These issues include the measurement and description of fields and exposures, and the ability of ultrasound to affect tissue (through microstreaming, streaming, cavitation, heating, etc.). It is noted that there are two very distinct regimes, in terms of wave characteristics and potential for bioeffect. The first concerns the use of ultrasound in liquids/solids, for measurement or material processing. For biomedical applications (where these two processes are termed diagnosis and therapy, respectively), the issue of hazard has been studied in depth, although this has not been done to such a degree for industrial uses of ultrasound in liquids/solids (sonar, non-destructive testing, ultrasonic processing etc.). However, in the second regime, that of the use of ultrasound in air, although the waves in question tend to be of much lower intensities than those used in liquids/solids, there is a greater mismatch between the extent to which hazard has been studied, and the growth in commercial applications for airborne ultrasound. PMID:17045633

Leighton, Timothy G

2006-08-15

265

One-pot three-component Mannich-type reactions using sulfamic acid catalyst under ultrasound irradiation.  

PubMed

Sulfamic acid (NH(2)SO(3)H, SA) was used as an efficient, inexpensive, non-toxic and recyclable green catalyst for the ultrasound-assisted one-pot Mannich reaction of aldehydes with ketones and amines. This ultrasound protocol has advantages of high yield, mild condition, no environmental pollution, and simple work-up procedures. Most importantly, beta-aminocarbonyl compounds with ortho-substituted aromatic amines are obtained in acceptable to good yields by this methodology for the first time. PMID:19394889

Zeng, Hongyao; Li, Hua; Shao, Huawu

2009-03-27

266

Controlling collagen fiber microstructure in three-dimensional hydrogels using ultrasound.  

PubMed

Type I collagen is the primary fibrillar component of the extracellular matrix, and functional properties of collagen arise from variations in fiber structure. This study investigated the ability of ultrasound to control collagen microstructure during hydrogel fabrication. Under appropriate conditions, ultrasound exposure of type I collagen during polymerization altered fiber microstructure. Scanning electron microscopy and second-harmonic generation microscopy revealed decreased collagen fiber diameters in response to ultrasound compared to sham-exposed samples. Results of mechanistic investigations were consistent with a thermal mechanism for the effects of ultrasound on collagen fiber structure. To control collagen microstructure site-specifically, a high frequency, 8.3-MHz, ultrasound beam was directed within the center of a large collagen sample producing dense networks of short, thin collagen fibrils within the central core of the gel and longer, thicker fibers outside the beam area. Fibroblasts seeded onto these gels migrated rapidly into small, circularly arranged aggregates only within the beam area, and clustered fibroblasts remodeled the central, ultrasound-exposed collagen fibrils into dense sheets. These investigations demonstrate the capability of ultrasound to spatially pattern various collagen microstructures within an engineered tissue noninvasively, thus enhancing the level of complexity of extracellular matrix microenvironments and cellular functions achievable within three-dimensional engineered tissues. PMID:23927189

Garvin, Kelley A; VanderBurgh, Jacob; Hocking, Denise C; Dalecki, Diane

2013-08-01

267

Interventional ultrasound  

SciTech Connect

This book discusses: Introduction to interventional ultrasound/handling of aspirated material/general principles of fine needle aspiration cytology/procedure and principles in ultrasonically guided puncture/puncture of focal liver lesions/intraoperative puncture of the liver guided by ultrasound/Interventional ultrasound in cancer therapy/Interventional echocardiography/Fine-needle aspiration biopsy: Are there any risks./Puncture of renal mass lesions/Intrauterine needle diagnosis/Percutaneous nephrolithotomy.

Holm, H.H.; Kristensen, J.K.

1985-01-01

268

Quantitative Ultrasound Backscatter for Pulsed Cavitational Ultrasound Therapy--Histotripsy  

PubMed Central

Histotripsy is a well-controlled ultrasonic tissue ablation technology that mechanically and progressively fractionates tissue structures using cavitation. The fractionated tissue volume can be monitored with ultrasound imaging because a significant ultrasound backscatter reduction occurs. This paper correlates the ultrasound backscatter reduction with the degree of tissue fractionation characterized by the percentage of remaining normal-appearing cell nuclei on histology. Different degrees of tissue fractionation were generated in vitro in freshly excised porcine kidneys by varying the number of therapeutic ultrasound pulses from 100 to 2000 pulses per treatment location. All ultrasound pulses were 15 cycles at 1 MHz delivered at 100 Hz pulse repetition frequency and 19 MPa peak negative pressure. The results showed that the normalized backscatter intensity decreased exponentially with increasing number of pulses. Correspondingly, the percentage of normal appearing nuclei in the treated area decreased exponentially as well. A linear correlation existed between the normalized backscatter intensity and the percentage of normal appearing cell nuclei in the treated region. This suggests that the normalized backscatter intensity may be a potential quantitative real-time feedback parameter for histotripsy-induced tissue fractionation. This quantitative feedback may allow the prediction of local clinical outcomes, i.e., when a tissue volume has been sufficiently treated.

Wang, Tzu-Yin; Xu, Zhen; Winterroth, Frank; Hall, Timothy L.; Fowlkes, J. Brian; Rothman, Edward D.; Roberts, William W.; Cain, Charles A.

2011-01-01

269

Intrathyroidal Branchial Cleft-like Cyst with Heterotopic Salivary Gland-type Tissue  

Microsoft Academic Search

A rare case is described of intrathyroidal branchial cleft-like cyst associated with unusual heterotopic tissues including the salivary gland type tissue, fat, and cartilage. This coexistence in the thyroid gland has not been described previously, to our knowledge. The patient was a 7-year-old girl with a growing mass in the left lateral neck. The ultrasonography revealed a cystic lesion in

Ji-Young Park; Gou Young Kim; Yeon-Lim Suh

2004-01-01

270

Tracked ultrasound elastography (TRUE)  

NASA Astrophysics Data System (ADS)

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

Foroughi, Pezhman

271

Modulation of ultrasound to produce multifrequency radiation force1  

PubMed Central

Dynamic radiation force has been used in several types of applications, and is performed by modulating ultrasound with different methods. By modulating ultrasound, energy can be transmitted to tissue, in this case a dynamic force to elicit a low frequency cyclic displacement to inspect the material properties of the tissue. In this paper, different types of modulation are explored including amplitude modulation (AM), double sideband suppressed carrier amplitude modulation AM, linear frequency modulation, and frequency-shift keying. Generalized theory is presented for computing the radiation force through the short-term time average of the energy density for these various types of modulation. Examples of modulation with different types of signals including sine waves, square waves, and triangle waves are shown. Using different modulating signals, multifrequency radiation force with different numbers of frequency components can be created, and can be used to characterize tissue mimicking materials and soft tissue. Results for characterization of gelatin phantoms using a method of vibrating an embedded sphere are presented. Different degrees of accuracy were achieved using different modulation techniques and modulating signals. Modulating ultrasound is a very flexible technique to produce radiation force with multiple frequency components that can be used for various applications.

Urban, Matthew W.; Fatemi, Mostafa; Greenleaf, James F.

2010-01-01

272

Modulation of ultrasound to produce multifrequency radiation force.  

PubMed

Dynamic radiation force has been used in several types of applications, and is performed by modulating ultrasound with different methods. By modulating ultrasound, energy can be transmitted to tissue, in this case a dynamic force to elicit a low frequency cyclic displacement to inspect the material properties of the tissue. In this paper, different types of modulation are explored including amplitude modulation (AM), double sideband suppressed carrier amplitude modulation AM, linear frequency modulation, and frequency-shift keying. Generalized theory is presented for computing the radiation force through the short-term time average of the energy density for these various types of modulation. Examples of modulation with different types of signals including sine waves, square waves, and triangle waves are shown. Using different modulating signals, multifrequency radiation force with different numbers of frequency components can be created, and can be used to characterize tissue mimicking materials and soft tissue. Results for characterization of gelatin phantoms using a method of vibrating an embedded sphere are presented. Different degrees of accuracy were achieved using different modulation techniques and modulating signals. Modulating ultrasound is a very flexible technique to produce radiation force with multiple frequency components that can be used for various applications. PMID:20329821

Urban, Matthew W; Fatemi, Mostafa; Greenleaf, James F

2010-03-01

273

Constrained Least Squares Filtering Algorithm for Ultrasound Image Deconvolution  

Microsoft Academic Search

A new medical ultrasound tissue model is considered in this paper, which incorporates random fluctuations of the tissue response and provides more realistic interpretation of the received pulse-echo ultrasound signal. Using this new model, we propose an algorithm for restoration of the degraded ultrasound image. The proposed deconvolution is a modification of the classical regularization technique which combines Wiener filter

Wee-Soon Yeoh; Cishen Zhang

2006-01-01

274

Posttranslational modifications in type I collagen from different tissues extracted from wild type and prolyl 3-hydroxylase 1 null mice.  

PubMed

Type I collagen extracted from tendon, skin, and bone of wild type and prolyl 3-hydroxylase 1 (P3H1) null mice shows distinct patterns of 3-hydroxylation and glycosylation of hydroxylysine residues. The A1 site (Pro-986) in the ?1-chain of type I collagen is almost completely 3-hydroxylated in every tissue of the wild type mice. In contrast, no 3-hydroxylation of this proline residue was found in P3H1 null mice. Partial 3-hydroxylation of the A3 site (Pro-707) was present in tendon and bone, but absent in skin in both ?-chains of the wild type animals. Type I collagen extracted from bone of P3H1 null mice shows a large reduction in 3-hydroxylation of the A3 site in both ?-chains, whereas type I collagen extracted from tendon of P3H1 null mice shows little difference as compared with wild type. These results demonstrate that the A1 site in type I collagen is exclusively 3-hydroxylated by P3H1, and presumably, this enzyme is required for the 3-hydroxylation of the A3 site of both ?-chains in bone but not in tendon. The increase in glycosylation of hydroxylysine in P3H1 null mice in bone was found to be due to an increased occupancy of normally glycosylated sites. Despite the severe disorganization of collagen fibrils in adult tissues, the D-period of the fibrils is unchanged. Tendon fibrils of newborn P3H1 null mice are well organized with only a slight increase in diameter. The absence of 3-hydroxyproline and/or the increased glycosylation of hydroxylysine in type I collagen disturbs the lateral growth of the fibrils. PMID:23861401

Pokidysheva, Elena; Zientek, Keith D; Ishikawa, Yoshihiro; Mizuno, Kazunori; Vranka, Janice A; Montgomery, Nathan T; Keene, Douglas R; Kawaguchi, Tatsuya; Okuyama, Kenji; Bächinger, Hans Peter

2013-07-16

275

Renal ultrasound elastography.  

PubMed

Chronic kidney disease (CKD) incidence and prevalence are increasing in Western countries, due particularly to diabetes mellitus and hypertension-related nephropathies. CKD may lead to end-stage renal failure, with extensive morbidity, mortality and increasing health costs. Primary and secondary prevention requires a better knowledge of mechanisms underlying renal scarring, the development of specific therapies to slow down the progression of the disease and the development of non-invasive diagnostic tools to characterize the process. Ultrasound elastography is a new imaging technique under development that provides information about renal stiffness. Kidney elasticity measurements with ultrasound should be performed with a quantitative technique, such as Shearwave techniques. However kidney stiffness is not only related to fibrosis, as it also sensitive to mechanical and functional parameters such as anisotropy, vascularization, hydronephrosis and external pressure. This paper reviews the existing ultrasound elastography techniques. Elastography is a new tool under development for renal tissue characterization and needs further validation in clinical practice. PMID:23567180

Grenier, N; Gennisson, J-L; Cornelis, F; Le Bras, Y; Couzi, L

2013-04-06

276

Tissue-specific expression of the human type II collagen gene in mice  

SciTech Connect

Type II collagen is crucial to the development of form in vertebrates as it is the major protein of cartilage. To study the factors regulating its expression the authors introduced a cosmid containing the human type II collagen gene, including 4.5 kilobases of 5' and 2.2 kilobases of 3' flanking DNA, into embryonic stem cells in vitro. The transformed cells contribute to all tissues in chimeric mice allowing the expression of the exogenous gene to be studied in vivo. Human type II collagen mRNA is restricted to tissues showing transcription from the endogenous gene and human type II collagen is found in extracellular matrix surrounding chondrocytes in cartilage. The results indicate that the cis-acting requirements for correct temporal and spatial regulation of the gene are contained with the introduced DNA.

Lovell-Badge, R.H.; Bygrave, A.; Bradley, A.; Robertson, E.; Tilly, R.; Cheah, K.S.E.

1987-05-01

277

X-ray scattering for classifying tissue types associated with breast disease  

SciTech Connect

Collagen types I and III can be characterized at the molecular level (at the tens to hundreds of nanometers scale) using small angle x-ray scattering (SAXS). Although collagen fibril structural parameters at this length scale have shown differences between diseased and nondiseased breast tissues, a comprehensive analysis involving a multitude of features with a large (>50) patient cohort has not previously been investigated. Breast tissue samples were excised from 80 patients presenting with either a breast lump or reduction mammoplasty. From these, invasive carcinoma, benign tissue, and normal parenchyma were analyzed. Parameters related to collagen structure, including longitudinal (axial) and lateral (equatorial) features, polar angle features, total scattering intensity, and tissue heterogeneity effects, were extracted from the SAXS patterns and examined. The amplitude of the third-order axial peak and the total scattering intensity (amorphous scatter) showed the most separation between tissue groups and a classification model using these two parameters demonstrated an accuracy of over 95% between invasive carcinoma and mammoplasty patients. Normal tissue taken from disease-free patients (mammoplasty) and normal tissue taken from patients with presence of disease showed significant differences, suggesting that SAXS may provide different diagnostic information from that of conventional histopathology.

Sidhu, Sabeena; Siu, Karen K. W.; Falzon, Gregory; Nazaretian, Simon; Hart, Stewart A.; Fox, Jane G.; Susil, Beatrice J.; Lewis, Robert A. [Monash Centre for Synchrotron Science, and School of Physics, Monash University, Clayton, Victoria 3800 (Australia); School of Science and Technology, University of New England, Armidale, New South Wales 2351 (Australia); Department of Anatomical Pathology, The Royal Women's Hospital, Carlton, Victoria 3053, Australia, Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria 3800, Australia, and Department of Pathology, Monash Medical Centre, Clayton, Victoria 3168 (Australia); Department of Surgery, Monash Medical Centre, Clayton, Victoria 3168, Australia and Monash Breast Unit, Monash Medical Centre, Moorabin, Victoria 3165 (Australia); Department of Surgery, Monash Medical Centre, Clayton, Victoria 3168, Australia and Monash Breast Unit, Monash Medical Centre, Moorabin, Victoria 3165 (Australia); Department of Pathology, Monash Medical Centre, Clayton, Victoria 3168, Australia and Monash Breast Unit, Monash Medical Centre, Moorabin, Victoria 3165 (Australia); Monash Centre for Synchrotron Science, and School of Physics, Monash University, Clayton, Victoria 3800 (Australia)

2008-10-15

278

11?-HSD Type 1 Expression in Human Adipose Tissue: Impact of Gender, Obesity, and Fat Localization  

Microsoft Academic Search

Objective: Pre-receptor amplification of glucocorticoids is, in part, determined by the isoenzymes 11?-hydroxysteroid dehydrogenase (11?-HSD) type 1 and type 2, interconverting inert cortisone and active cortisol. Increased tissue activity of cortisol may play a part in features of the metabolic syndrome. Our objective was to compare 11?-HSD1 gene expression in different fat depots (visceral, subcutaneous abdominal, and subcutaneous gluteal) in

Søren Kildeberg Paulsen; Steen Bønløkke Pedersen; Sanne Fisker; Bjørn Richelsen

2007-01-01

279

Ultrasound growth parameters in relation to levels of amniotic fluid insulin in women with diabetes type-I  

Microsoft Academic Search

The aim of the study was to investigate the correlation between ultrasound parameters and levels of amniotic fluid insulin (AF-insulin) in pregnancies complicated by insulin-dependent diabetes mellitus (IDDM). In 129 women with IDDM amniocentesis was performed between 28 and 35 weeks of gestation. The levels of AF-insulin were measured by radioimmunoassay (Pharmacia RIA 100®) and were correlated with biparietal diameter

Franz Kainer; Peter A. M. Weiss; Ulla Hüttner; Josef Haas

1997-01-01

280

Immunocytochemical Localization of Type 5 17 b -Hydroxysteroid Dehydrogenase in Human Reproductive Tissues  

Microsoft Academic Search

SUMMARY 17 b -hydroxysteroid dehydrogenase (17 b -HSD) controls the last step in the for- mation of all androgens and all estrogens. At least six 17 b -HSD isoenzymes have been iden- tified. The recently cloned Type 5 17 b -HSD transforms 4-dione into testosterone. To gain a better understanding of the role of this enzyme in reproductive tissues, we

Georges Pelletier; Bernard Têtu; Fernand Labrie

281

An active-site titrant for human tissue-type plasminogen activator.  

PubMed Central

The reaction of recombinant tissue-type plasminogen activator with the inverse substrate 4-amidino-2-nitrophenyl 4'-anisate results in the rapid release of the chromogen 4-amidino-2-nitrophenol and the accumulation of the relatively stable 4-anisoyl-enzyme. Spectrophotometric monitoring of the reaction enables the operational molarity of the enzyme to be determined.

Smith, R A

1986-01-01

282

Fragile Sites on Human Chromosomes: Demonstration of Their Dependence on the Type of Tissue Culture Medium  

Microsoft Academic Search

The observation of heritable fragile sites on human chromosomes prepared from lymphocyte cultures has been shown to depend on the type of tissue culture medium in which the lymphocytes are grown. The sites are observed at a much greater frequency when medium 199 is used than when RPMI 1640, Ham's F10, Eagle's (basal), and CMRL 1969 are used. One site

Grant R. Sutherland

1977-01-01

283

Ultrasound-enhanced delivery of targeted echogenic liposomes in a novel ex vivo mouse aorta model  

PubMed Central

The goal of this study was to determine whether targeted, Rhodamine-labeled echogenic liposomes (Rh-ELIP) containing nanobubbles could be delivered to the arterial wall, and whether 1 MHz continuous wave ultrasound would enhance this delivery profile. Aortae excised from apolipoprotein-E-deficient (n = 8) and wild-type (n = 8) mice were mounted in a pulsatile flow system through which Rh-ELIP were delivered in a stream of bovine serum albumin. Half the aortae from each group were treated with 1-MHz continuous wave ultrasound at 0.49 MPa peak-to-peak pressure, and half underwent sham exposure. Ultrasound parameters were chosen to promote stable cavitation and avoid inertial cavitation. A broadband hydrophone was used to monitor cavitation activity. After treatment, aortic sections were prepared for histology and analyzed by an individual blinded to treatment conditions. Delivery of Rh-ELIP to the vascular endothelium was observed, and subendothelial penetration of Rh-ELIP was present in five of five ultrasound-treated aortae and was absent in those not exposed to ultrasound. However, the degree of penetration in the ultrasound-exposed aortae was variable. There was no evidence of ultrasound-mediated tissue damage in any specimen. Ultrasound-enhanced delivery within the arterial wall was demonstrated in this novel model, which allows quantitative evaluation of therapeutic delivery.

Hitchcock, Kathryn E.; Caudell, Danielle N.; Sutton, Jonathan T.; Klegerman, Melvin E.; Vela, Deborah; Pyne-Geithman, Gail J.; Abruzzo, Todd; Cyr, Peppar E. P.; Geng, Yong-Jian; McPherson, David D.; Holland, Christy K.

2010-01-01

284

Effect of Immersion Time in Osmosis and Ultrasound on Papaya Cell Structure during Dehydration  

Microsoft Academic Search

The effect of ultrasound-assisted osmotic dehydration applied at atmospheric pressure for different lengths of time on papaya tissue structure was evaluated. Ultrasound induced the loss of cellular adhesion, formation of large cell interspaces, and light rupture of the cell walls. The changes in the tissue structure caused by ultrasound application increased sugar loss, water loss, and effective water diffusivity. Ultrasound-assisted

Sueli Rodrigues; Francisca I. P. Oliveira; Maria Izabel Gallão; Fabiano A. N. Fernandes

2009-01-01

285

Synchrotron FTIR Imaging For The Identification Of Cell Types Within Human Tissues  

SciTech Connect

The use of synchrotron Fourier Transform Infrared spectroscopy (S-FTIR) has been shown to be a very promising tool for biomedical research. S-FTIR spectroscopy allows for the fast acquisition of infrared (IR) spectra at a spatial resolution approaching the IR diffraction limit. The development of the Infrared Environmental Imaging (IRENI) beamline at the Synchrotron Radiation Center (SRC) at the University of Wisconsin-Madison has allowed for diffraction limited imaging measurements of cells in human prostate and breast tissues. This has allowed for the identification of cell types within tissues that would otherwise not have been resolvable using conventional FTIR sources.

Walsh, Michael J.; Pounder, F. Nell [Beckman Institute, University of Illinois, 405 N Mathews Ave, Urbana, Il 61801 (United States); Nasse, Michael J. [University of Wisconsin-Milwaukee, Department of Physics, 1900 E. Kenwood Blvd., Milwaukee, WI, 53211 (United States); Synchrotron Radiation Center, University of Wisconsin-Madison 3731 Schneider Dr., Stoughton, WI 53589 (United States); Macias, Virgilia; Kajdacsy-Balla, Andre [Department of Pathology, University of Illinois at Chicago, 840 S. Wood St. Chicago, Il. 60612 (United States); Hirschmugl, Carol [University of Wisconsin-Milwaukee, Department of Physics, 1900 E. Kenwood Blvd., Milwaukee, WI, 53211 (United States); Bhargava, Rohit [Beckman Institute, University of Illinois, 405 N Mathews Ave, Urbana, Il 61801 (United States); Bioengineering Department, University of Illinois, 1304 West Springfield Avenue Urbana, IL 61801 (United States)

2010-02-03

286

Hip Ultrasound  

MedlinePLUS

... quickly. The ultrasound exam room may have a television. Feel free to ask for your child's favorite ... display screen that looks like a computer or television monitor. The image is created based on the ...

287

Ultrasound -- Vascular  

MedlinePLUS

... quickly. The ultrasound exam room may have a television. Feel free to ask for your child's favorite ... display screen that looks like a computer or television monitor. The image is created based on the ...

288

Musculoskeletal Ultrasound  

MedlinePLUS

... quickly. The ultrasound exam room may have a television. Feel free to ask for your child's favorite ... display screen that looks like a computer or television monitor. The image is created based on the ...

289

Ultrasound -- Pelvis  

MedlinePLUS Videos and Cool Tools

... to ease anxiety. Ultrasound departments often have a television in the examination room and the child's favorite ... display screen that looks like a computer or television monitor. The image is created based on the ...

290

Obstetrical Ultrasound  

MedlinePLUS

... or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the ... probe through the gel into the body. The transducer collects the sounds that bounce back and a ...

291

Scrotal Ultrasound  

MedlinePLUS

... or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the ... probe through the gel into the body. The transducer collects the sounds that bounce back and a ...

292

Prostate Ultrasound  

MedlinePLUS

... or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the ... probe through the gel into the body. The transducer collects the sounds that bounce back and a ...

293

Abdominal Ultrasound  

MedlinePLUS

... or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the ... probe through the gel into the body. The transducer collects the sounds that bounce back and a ...

294

Ultrasound-modulated optical microscopy.  

PubMed

We demonstrate that microscopic imaging is feasible in ultrasound-modulated optical tomography (UOT) of soft biological tissues, using a high-frequency focused ultrasound transducer with a 75-MHz central frequency. Our experiments in tissue mimicking phantoms show that at an imaging depth of about 2 mm, an axial resolution better than 30 microm can be achieved, whereas the lateral resolution is 38 microm. A long-cavity scanning confocal Fabry-Perot interferometer (CFPI) is used for real-time detection of multiply scattered light modulated by high-frequency ultrasound pulses propagating in an optically scattering medium. We also compare the performances of various high-frequency focused ultrasound transducers with central frequencies of 15 MHz, 30 MHz, 50 MHz, and 75 MHz. The comparison is based on two-dimensional (2-D) images of optically absorbing objects positioned at a few millimeters depth below the surface of both optically scattering phantoms and soft biological tissue samples. Our experimental results show that modulation depth and image contrast decrease with an increase in ultrasound frequency. In addition, we use analytical calculations to show that modulation depth decreases with increasing ultrasound frequency. PMID:19021426

Kothapalli, Sri-Rajasekhar; Wang, Lihong V

295

SPECIAL ISSUE DEVOTED TO MULTIPLE RADIATION SCATTERING IN RANDOM MEDIA: Opto-acoustic diagnostics of the thermal action of high-intensity focused ultrasound on biological tissues: the possibility of its applications and model experiments  

NASA Astrophysics Data System (ADS)

The possibility of using the opto-acoustic (OA) method for monitoring high-intensity ultrasonic therapy is studied. The optical properties of raw and boiled liver samples used as the undamaged model tissue and tissue destroyed by ultrasound, respectively, are measured. Experiments are performed with samples consisting of several alternating layers of raw and boiled liver of different thickness. The position and transverse size of the thermal lesion were determined from the temporal shape of the OA signals. The results of measurements are compared with the real size and position of the thermal lesion determined from the subsequent cuts of the sample. It is shown that the OA method permits the diagnostics of variations in biological tissues upon ultrasonic therapy.

Khokhlova, Tanya D.; Pelivanov, Ivan M.; Sapozhnikov, Oleg A.; Solomatin, Vladimir S.; Karabutov, Aleksander A.

2006-12-01

296

Cardiac arrhythmias produced by ultrasound and contrast agents  

NASA Astrophysics Data System (ADS)

Ultrasound is used widely in medicine for both diagnostic and therapeutic applications. Ultrasound contrast agents are suspensions of gas-filled microbubbles used to enhance diagnostic imaging. Microbubble contrast agents can increase the likelihood of bioeffects of ultrasound associated with acoustic cavitation. Under certain exposure conditions, the interaction of ultrasound with cardiac tissues can produce cardiac arrhythmias. The general objective of this thesis was to develop a greater understanding of ultrasound-induced premature cardiac beats. The hypothesis guiding this work was that acoustic cavitation is the physical mechanism for the production of arrhythmias with ultrasound. This hypothesis was tested through a series of experiments with mice in vivo and theoretical investigations. Results of this research supported the acoustic cavitation hypothesis. The acoustic pressure threshold for premature beats was significantly lower with microbubble contrast agents present in the blood than without. With microbubbles, the threshold for premature beats was below the current output limits of diagnostic devices. The threshold was not significantly dependent upon contrast agent type and was not influenced by contrast agent dose over three orders of magnitude. Furthermore, the dependence of the threshold on acoustic frequency was consistent with the frequency dependence of acoustic cavitation. Experimentally determined thresholds for premature beats in vivo were in excellent agreement with theoretically estimated thresholds for inertial cavitation. A passive cavitation detector (PCD) was used to measure the acoustic emissions produced by cavitating microbubbles in vivo. A direct correlation between the amplitude of the PCD and the percentage of ultrasound pulses producing a premature beat was consistent with cavitation as a mechanism for this bioeffect. Although this thesis focused on the mechanistic understanding of ultrasound-induced arrhythmias, more persistent effects on the murine heart were also discovered. In the presence of microbubbles, ultrasound could produce morphological changes in the ECG and vascular damage in the myocardium. Taken together, these results indicate that ultrasound-induced arrhythmias were produced by intravascular microbubble activity. The findings of this thesis provide a greater understanding of acoustic cavitation in vivo, useful for the advancement of ultrasound contrast agents in imaging and therapy.

Rota, Claudio

297

Complex heterogeneous tissue constructs containing multiple cell types prepared by inkjet printing technology.  

PubMed

This study was designed to develop a versatile method for fabricating complex and heterogeneous three-dimensional (3D) tissue constructs using simultaneous ink-jetting of multiple cell types. Human amniotic fluid-derived stem cells (hAFSCs), canine smooth muscle cells (dSMCs), and bovine aortic endothelial cells (bECs), were separately mixed with ionic cross-linker calcium chloride (CaCl(2)), loaded into separate ink cartridges and printed using a modified thermal inkjet printer. The three cell types were delivered layer-by-layer to pre-determined locations in a sodium alginate-collagen composite located in a chamber under the printer. The reaction between CaCl(2) and sodium alginate resulted in a rapid formation of a solid composite gel and the printed cells were anchored in designated areas within the gel. The printing process was repeated for several cycles leading to a complex 3D multi-cell hybrid construct. The biological functions of the 3D printed constructs were evaluated in vitro and in vivo. Each of the printed cell types maintained their viability and normal proliferation rates, phenotypic expression, and physiological functions within the heterogeneous constructs. The bioprinted constructs were able to survive and mature into functional tissues with adequate vascularization in vivo. These findings demonstrate the feasibility of fabricating complex heterogeneous tissue constructs containing multiple cell types using inkjet printing technology. PMID:23063369

Xu, Tao; Zhao, Weixin; Zhu, Jian-Ming; Albanna, Mohammad Z; Yoo, James J; Atala, Anthony

2012-10-10

298

Secretome analysis of rat adipose tissues shows location-specific roles for each depot type.  

PubMed

Obesity prevalence is reaching pandemic proportions becoming a major public health threat for many industrialized nations. It is especially worrying as it causes a higher risk of premature death due to associated diseases such as type 2 diabetes, cardiovascular disease, and some cancers. Current evidence shows biological and genetic differences between adipose tissues depending on its anatomical location. Particularly, upper body/visceral fat distribution in obesity is closely linked to metabolic complications. In this report, we characterize for the first time the secretome of rat adipose tissue explants from different anatomical localizations and its differential analysis. Visceral, subcutaneous, and gonadal fat specific secretomes and differentially secreted proteins among the three fat depots were analyzed by 2-DE and MS. Reference maps for location-specific adipose tissue secretomes are shown and the 45 most significant differences are listed. Identified proteins include classical adipokines and novel secreted proteins. Interestingly, our results show that the type of proteins and their role in different biological processes diverge significantly when comparing the set of proteins identified from visceral, subcutaneous and gonadal fat explants. This study emphasizes and supports the differential role of adipose tissue in accordance to its anatomical localization. PMID:21439414

Roca-Rivada, Arturo; Alonso, Jana; Al-Massadi, Omar; Castelao, Cecilia; Peinado, Juan Ramón; Seoane, Luisa María; Casanueva, Felipe F; Pardo, María

2011-03-23

299

Ultrasound in analytical chemistry.  

PubMed

Ultrasound is a type of energy which can help analytical chemists in almost all their laboratory tasks, from cleaning to detection. A generic view of the different steps which can be assisted by ultrasound is given here. These steps include preliminary operations usually not considered in most analytical methods (e.g. cleaning, degassing, and atomization), sample preparation being the main area of application. In sample preparation ultrasound is used to assist solid-sample treatment (e.g. digestion, leaching, slurry formation) and liquid-sample preparation (e.g. liquid-liquid extraction, emulsification, homogenization) or to promote heterogeneous sample treatment (e.g. filtration, aggregation, dissolution of solids, crystallization, precipitation, defoaming, degassing). Detection techniques based on use of ultrasonic radiation, the principles on which they are based, responses, and the quantities measured are also discussed. PMID:17103146

Priego Capote, F; Luque de Castro, M D

2006-11-14

300

Breast biopsy - ultrasound  

MedlinePLUS

Biopsy - breast - ultrasound; Ultrasound-guided breast biopsy; Core needle breast biopsy - ultrasound ... to be biopsied. The doctor will use an ultrasound machine to guide the needle to the abnormal ...

301

Ultrasound applicators for interstitial thermal coagulation  

Microsoft Academic Search

Direct-coupled (DC) and catheter-cooled (CC) ultrasound applicator configurations were evaluated for high-temperature ultrasound interstitial thermal therapy (USITT) using computer simulations, acoustic beam measurements, and in vivo temperature measurements. The DC devices consist of 2.2-mm diameter tubular ultrasound transducers encapsulated within a thin biocompatible plastic coating, which can be inserted directly into the tissue. The CC devices incorporate 1.5-mm diameter tubular

Chris J. Diederich; William H. Nau; Paul R. Stauffer

1999-01-01

302

Tissue-specific regulation and expression of heat shock proteins in type 2 diabetic monkeys  

Microsoft Academic Search

The chaperone protein heat shock protein (HSP) 70 has been shown to protect against obesity-associated insulin resistance.\\u000a Induction of HSPs is thus considered an exciting therapeutic strategy for diabetes (DM). The aims of this study were to (1)\\u000a determine HSP levels in plasma, hepatic, and pancreatic tissues of type 2 DM primates and (2) assess the relationship between\\u000a chaperone proteins

K. Kavanagh; Li Zhang; Janice D. Wagner

2009-01-01

303

Combination Therapy Stroke Trial: Recombinant Tissue-Type Plasminogen Activator with\\/without Lubeluzole  

Microsoft Academic Search

Background: A neuroprotective drug may be safe and effective if given very early and in combination with recombinant tissue-type plasminogen activator (rt-PA) to acute stroke patients. No clinical trial has yet tested this hypothesis. Objective: To assess the feasibility, safety and efficacy of simultaneously combining the neuroprotective drug lubeluzole with rt-PA. Method: Patients who qualified for and received rt-PA within

James Grotta

2001-01-01

304

MEASUREMENT OF CHANGES IN TISSUE METABOLISM USING A CLARK-TYPE OXYGEN SENSOR  

Microsoft Academic Search

This paper presents data characterizing the ability to measure metabolic activity at a tissue interface using a Clark-type oxygen concentration sensor consisting of a microfabricated thin- film electrode matrix overlaid with a solid-state proton conductive matrix and encapsulated in a bio-inert polytetrafluoroethylene film. HL-1 atrial myocytes were cultured onto the sensor surface. Cyclic voltammetry was utilized to characterize the sensor

Benjamin Franc; Nathalia Peixoto; Laurent Giovangrandi; Glen McLaughlin; Gregory T. A. Kovacs

2002-01-01

305

Increased expression of tissue-type transglutaminase following middle cerebral artery occlusion in rats  

Microsoft Academic Search

Tissue-type transglutaminase (TG-2) has been implicated in neurodegenerative diseases. In this study, induction of TG-2 was studied in rats following transient middle cerebral artery occlusion. Alterations in 2,3,5-triphenylterazolium chloride staining revealed maximum infarction 3 days after injury. Measurement of mRNA transcript levels by real-time PCR analysis showed both forms of TG-2 mRNA peaking on day 5 after injury in ipsilateral

Paul J. Tolentino; Anuradha Waghray; Kevin K. W. Wang; Ronald L. Hayes

2004-01-01

306

Peroxynitrite: A Key Molecule in Skin Tissue Response to Different Types of Stress  

Microsoft Academic Search

Skin, the largest tissue exposed to a variety of stresses demonstrates a common cellular biochemical response unrelated to\\u000a the type of the stress allegedly. In this chapter we will describe a phenomenon in which different insults, unrelated to oxidative\\u000a events to start with, resulted in an activation of common cellular biochemical pathways. These processes are similar to those\\u000a evoked following

Meital Portugal; Ron Kohen

307

Tissue-type plasminogen activator modulates inflammatory responses and renal function in ischemia reperfusion injury  

Microsoft Academic Search

Acute renal failure is often the result of ischemia-reperfusion (I\\/R) injury. Neutrophil influx is an important damaging event in I\\/R. Tissue-type plasminogen activator (tPA) not only is a major fibrinolytic agent but also is involved in inflammatory processes. A distinct upregulation of tPA after I\\/R, with de novo tPA production by proximal renal tubules, was found. For investigating the role

Joris J. T. H. Roelofs; Kasper M. A. Rouschop; Jaklien C. Leemans; Nike Claessen; Boer de A. M; Wilma M. Frederiks; H. Roger Lijnen; Jan J. Weening; Sandrine Florquin

2006-01-01

308

A- and B-type lamins are differentially expressed in normal human tissues  

Microsoft Academic Search

A selection of normal human tissues was investigated for the presence of lamins B1, B2, and A-type lamins, using a panel\\u000a of antibodies specific for the individual lamin subtypes. By use of immunoprecipitation and two-dimensional immunoblotting\\u000a techniques we demonstrated that these antibodies do not cross-react with other lamin subtypes and that a range of different\\u000a phosphorylation isoforms is recognized by

Jos L. V. Broers; Barbie M. Machiels; Helma J. H. Kuijpers; Frank Smedts; Ronald van den Kieboom; Yves Raymond; Frans C. S. Ramaekers

1997-01-01

309

Prognosis Is Correlated with p53 Mutation Type for Soft Tissue Sarcoma Patients1  

Microsoft Academic Search

We investigatedthe prognosticvalue ofpS3 mutationtype for 145 soft tissue sarcoma patients. In a PCR-SSCP-sequencing analysis, 15 mute tions were identified: 10 nonframeshift (non-fs) and 5 frameshift (fs) mutations. Patients possessing non-fs mutations had a significantly poorer prognosisthan patients withoutp53 mutations(P 0.014), accordingto Cox's multivariateanalysis. In contrast,the survivalof five patients with fs mutations was not affected by their mutation type. Furthermore,

Helge Taubert; Axel Meye

1996-01-01

310

Mechanisms of inhibited liver tissue repair in toxicant challenged type 2 diabetic rats  

Microsoft Academic Search

Liver injury initiated by non-lethal doses of CCl4 and thioacetamide (TA) progresses to hepatic failure and death of type 2 diabetic (DB) rats due to failed advance of liver cells from G0\\/G1 to S-phase and inhibited tissue repair. Objective of the present study was to investigate cellular signaling mechanisms of failed cell division in DB rats upon hepatotoxicant challenge. In

Sharmilee P. Sawant; Ankur V. Dnyanmote; Harihara M. Mehendale

2007-01-01

311

Extensive proliferation of mature connective-tissue type mast cells in vitro  

Microsoft Academic Search

There are two phenotypically distinct subpopulations of mast cells in rodents: connective tissue-type mast cells (CTMC) and mucosal mast cells (MMC). These populations differ in their location, cell size, staining characteristics, ultrastructure, mediator content and T-cell dependency1-3. Several investigators4-9 recently reported a further subclass of mast cells which arise when normal mouse haematopoietic cells are cultured with interleukin-3 (IL-3); IL-3

Tatsutoshi Nakahata; Toshimi Kobayashi; Akira Ishiguro; Kohichiro Tsuji; Kuniaki Naganuma; Osaaki Ando; Yoshio Yagi; Kenji Tadokoro; Taro Akabane

1986-01-01

312

Prostate thermal therapy with interstitial and transurethral ultrasound applicators: a feasibility study  

NASA Astrophysics Data System (ADS)

The purpose of this study was to determine the feasibility of using a transurethral ultrasound applicator in combination with implantable ultrasound applicators for inducing thermal coagulation and necrosis of localized cancer lesions or BPH within the prostate gland. The concept being evaluated is the potential to treat target zones in the anterior and lateral portions of the prostate with the transurethral applicator, while simultaneously treating regions of extracapsular extension and zones in the posterior prostate with the directive implantable applicators in combination with a rectal cooling bolus. Biothermal computer simulations, acoustic characterizations, and in vivo thermal dosimetry experiments were used to evaluate the performance of each applicator type and combinations thereof. The preliminary results of this investigation demonstrate that implantable ultrasound applicators, in combination with a transurethral ultrasound applicator, have the potential to provide thermal coagulation and necrosis of small or large regions within the prostate gland, while sparing thermally sensitive rectal tissue.

Diederich, Chris J.; Nau, William H.; Deardorff, Dana L.; Khalil-Bustany, Ismail S.; Burdette, Everette C.; Stauffer, Paul R.; Wu, Max

1998-04-01

313

Physical methods of reducing the transmission of nosocomial infections via ultrasound and probe.  

PubMed

Nosocomial infections are posing an increasingly serious problem in the hospital setting. With the increasing use of ultrasound in medical diagnosis, there is the potential for transmission of nosocomial infections via the ultrasound transducer and coupling gel. We evaluated the use of different membranes (three types of commercially available household cling film, condom, surgical glove and Opsite) applied over the ultrasound probe to determine if these were safe, convenient, cost-effective and did not impair the performance parameters of the ultrasound probe. None of the membranes impaired the physical scanning parameters using a Multi-Purpose Tissue/Cyst Phantom. The cling film was ideal for general use in terms of cost and convenience as well as safety. For sterile use the Opsite was better overall compared to the surgical glove, though it costs significantly more. The condom and surgical glove, though safe, were not very convenient to use for scanning. PMID:9528873

Abdullah, B J; Mohd Yusof, M Y; Khoo, B H

1998-03-01

314

Interactions between human immunodeficiency virus type 1 and vaccinia virus in human lymphoid tissue ex vivo.  

PubMed

Vaccinia virus (VACV) has been attracting attention recently not only as a vector for various vaccines but also as an immunization tool against smallpox because of its potential use as a bioterrorism agent. It has become evident that in spite of a long history of studies of VACV, its tissue pathogenesis remains to be fully understood. Here, we investigated the pathogenesis of VACV and its interactions with human immunodeficiency virus type 1 (HIV-1) in the context of human lymphoid tissues. We found that ex vivo-cultured tonsillar tissue supports productive infection by the New York City Board of Health strain, the VACV strain of the Dryvax vaccine. VACV readily infected both T and non-T (B) lymphocytes and depleted cells of both of these subsets equally over a 12-day period postinfection. Among T lymphocytes, CD8(+) cells are preferentially depleted in accordance with their preferential infection: the probability that a CD8(+) T cell will be productively infected is almost six times higher than for a CD4(+) T cell. T cells expressing CCR5 and the activation markers CD25, CD38, and HLA-DR are other major targets for infection by VACV in lymphoid tissue. As a consequence, VACV predominantly inhibits the replication of the R5(SF162) phenotype of HIV-1 in coinfected tissues, as R5-tropic HIV-1 requires activated CCR5(+) CD4(+) cells for productive infection. Human lymphoid tissue infected ex vivo by VACV can be used to investigate interactions of VACV with other viruses, in particular HIV-1, and to evaluate various VACV vectors for the purpose of recombinant vaccine development. PMID:17804502

Vanpouille, Christophe; Biancotto, Angélique; Lisco, Andrea; Brichacek, Beda

2007-09-05

315

Ultrasound microscope: the new field in ultrasound diagnostics  

NASA Astrophysics Data System (ADS)

A device which is a new stage in the development of medical equipment has been developed. The device works as an ultrasound microscope in vivo and provides 4 up to 32 colored histological image. It gives possibility to estimate tissue acoustic density with the help of 4 up to 32 gradation coloring different tissues and enables tissue microcirculation visualization. With the help of the device a doctor can objectify fatty hepatitis and cirrhosis, edema of different organs and tissues as well as microcirculation in organs and tissues (e.g. muscles, myocard and bone system). New promising applications of ultrasound systems in diagnostics and for choosing individual treatment tactics, with pathogenesis being taken into account, may be developed with the help of the device.

Novyc'kyy, Victor V.; Lushchyk, Ulyana B.

2001-06-01

316

MRI monitoring of high-temperature ultrasound therapy  

Microsoft Academic Search

More than fifty years ago, it was demonstrated that ultrasound could penetrate deep into tissue and induce a biological response. By focusing the ultrasound beam, localized heating in soft tissue is possible, allowing for a completely non-invasive technique to thermally ablate diseased tissue. Despite many promising results and advances in the last fifty years, widespread clinical implementation of therapeutic heating

Nathan Judson McDannold

2002-01-01

317

A 100-200 MHz ultrasound biomicroscope  

Microsoft Academic Search

The development of higher frequency ultrasound imaging systems affords a unique opportunity to visualize living tissue at the microscopic level. This work was undertaken to assess the potential of ultrasound imaging in vivo using the 100-200 MHz range. Spherically focused lithium niobate transducers were fabricated. The properties of a 200 MHz center frequency device are described in detail. This transducer

D. A. Knspik; Brian Starkoski; Charles J. Pavlin; F. Stuart Foster

2000-01-01

318

The role of ultrasound operation mode for safely interfering in the heart rate  

Microsoft Academic Search

Dia gnostic ultrasound applies low intensity acoustic waves to noninvasively investigate biological tissues. Higher intensities can alter tissue characteristics, and this is of interest for therapeutic ultrasound, when the occurrence of bioeffects is - to a certain extent - desirable for tissue healing. Relative to cardiology, diagnostic ultrasound is well established, whereas there is an unexplored potential for therapeutic applications.

E. Belassiano; R. Miller; E. Hartman; W. D. OaBrien; F. Buiochi; E. T. Costa

2011-01-01

319

Ultrasound-based visual servoing system for lithotripsy  

Microsoft Academic Search

Recently, lithotripsy (kidney stone treatment) using HIFU (high intensity focused ultrasound) was developed by researchers in therapeutic ultrasound field. The lithotripsy crushes kidney stones powder, therefore, do not harm to the surrounding tissues of the kidney stones. However, it is necessary to continuously emit high intensity ultrasound waves on a target kidney stone during treatment. Therefore, HIFU transducers should follow

Deukhee Lee; Norihiro Koizumi; Kohei Ota; Shin Yoshizawa; Akira Ito; Yukio Kaneko; Yoichiro Matsumoto; Mamoru Mitsuishi

2007-01-01

320

Physical mechanisms of the therapeutic effect of ultrasound (a review)  

Microsoft Academic Search

Therapeutic ultrasound is an emerging field with many medical applications. High intensity focused ultrasound (HIFU) provides the ability to localize the deposition of acoustic energy within the body, which can cause tissue necrosis and hemostasis. Similarly, shock waves from a lithotripter penetrate the body to comminute kidney stones, and transcutaneous ultrasound enhances the transport of chemotherapy agents. New medical applications

M. R. Bailey; V. A. Khokhlova; O. A. Sapozhnikov; S. G. Kargl; L. A. Crum

2003-01-01

321

Characterization of feline TRIM genes: molecular cloning, expression in tissues, and response to type I interferon.  

PubMed

Members of the tripartite motif (TRIM) protein family in mammals are responsible for various cellular processes. Previous studies have revealed that several TRIM proteins were induced by interferons (IFN) and that these proteins were involved in innate immune response against retroviral infection. Although retroviral infection is prevalent in domestic cats, the expression profiles and roles of feline TRIM genes against these viral infections are not well understood. In the present study, we examined tissue expression and IFN inducibility of nine feline TRIM genes. In addition, the complete coding sequences of six cloned TRIM genes were determined, and their structures were analyzed. Nine TRIM genes were expressed in feline tissues and five were up-regulated by type I IFN. The predicted amino acid sequence of six feline TRIM proteins showed high sequence similarities to other mammalian TRIM proteins, and suggest that feline TRIM genes are potentially involved in antiviral reactivity in IFN-mediated immune response. PMID:23497841

Koba, Ryota; Kokaji, Chika; Fujisaki, Gentoku; Oguma, Keisuke; Sentsui, Hiroshi

2013-02-27

322

Ultrasound-targeted microbubble destruction enhances gene transduction of adeno-associated virus in a less-permissive cell type, NIH/3T3  

PubMed Central

Adeno-associated virus (AAV) is a common vector utilized in gene therapy. The NIH/3T3 cell line, which is a potential induced pluripotent stem (iPS) cell type, was identified to be a less-permissive cell type to AAV due to its defective endosomal processing. Ultrasound-targeted microbubble destruction (UTMD) enhanced the gene transduction of AAV in permissive cells. However, there are no data concerning UTMD enhancement in less-permissive cells, and the exact mechanism of UTMD enhancement in cellular uptake is unclear. Greater knowledge concerning the rate-limiting steps in NIH/3T3 cells would aid in the elucidation of the mechanism of UTMD enhancement in the gene transduction of AAV. In the present study, UTMD enhanced the gene transduction of AAV in NIH/3T3 cells, suggesting that UTMD-enhanced AAV-mediated gene transduction may be beneficial for gene therapy in iPS cells. The dose dependence of UTMD enhancement indicated that mechanisms other than sonoporation were involved in the cellular uptake of AAV. However, UTMD did not greatly increase the gene transduction of AAV in NIH/3T3 cells. Additionally, the similar degree of enhancement in the two cell types resulted in no correlation between UTMD and endosomal processing. Future studies on UTMD-mediated AAV transduction in other non- or less-permissive cell types may aid in elucidating the exact mechanism of UTMD enhancement in cellular uptake.

JIN, LIFANG; LI, FAN; WANG, HUIPING; LI, YUNHUA; WEI, FANG; DU, LIANFANG

2013-01-01

323

Breast ultrasound elastography.  

PubMed

Elastography is a newly emerging study of interest that can be especially helpful when used as an adjunct to conventional B-mode ultrasound in evaluating breast lesions. It is estimated that 80% of breast lesions currently biopsied prove to be benign. Reducing that percentage is advantageous to both patients and the imaging community. The specificity of conventional ultrasound when added to a mammography work-up needs improvement. Adding elastography may improve specificity. This Directed Reading describes different acoustic techniques used to obtain an elastogram and evaluation of scoring procedures. Major technique differences exist in imaging the elastic properties of tissue. This article is a Directed Reading. Your access to Directed Reading quizzes for continuing education credit is determined by your continuing education preference. For access to other quizzes, go to www.asrt.org/store. PMID:21406711

Baldwin, Pat

324

Endobronchial Ultrasound  

Microsoft Academic Search

Complex technical problems interfered with the application of thoracic ultrasound (US) for studies and clinical research. Moreover, in contrast to radiologists, cardiologists, gastroenterologists, internists, obstetricians, gynecologists and others, pulmonologists were not trained in the basics of US images. However, endoscopic US methods were developed in the last 20 years and these methods also provided important results for pulmonologists. As soon

Franco Falcone; Flavio Fois; Daniele Grosso

2003-01-01

325

Effect of type I and type II collagen sponges as 3D scaffolds for hyaline cartilage-like tissue regeneration on phenotypic control of seeded chondrocytes in vitro  

Microsoft Academic Search

Biodegradable polymers have been adopted as materials of three-dimensional (3D) scaffolds for regenerating cartilage-like tissues by using tissue engineering. On the other hand, it is well recognized that phenotypic control of seeded chondrocytes is indispensable for constructing not fibrous but hyaline cartilage-like tissue. According to the context, type II collagen is focused as a candidate of scaffold materials for articular

Takahiro Ohno; Keizo Tanisaka; Yosuke Hiraoka; Takashi Ushida; Tamotsu Tamaki; Tetsuya Tateishi

2004-01-01

326

Amyloid neuropathy type is distinguished by mass spectrometric based proteomic analysis of nerve tissue  

PubMed Central

Objective To determine specific type of amyloid from nerve biopsies using laser microdissection (LMD) and mass spectrometry (MS) based proteomic analysis. Methods Twenty one nerve biopsies (17 sural, 3 sciatic, 1 root amyloidoma) infiltrated by amyloid were studied. Immunohistochemical subtyping was unable to determine the specific amyloid for these 21 cases, but the clinical diagnosis was made based on additional testing. Clinical diagnosis was made through evaluation of serum monoclonal proteins, biopsy of bone marrow for acquired monoclonal immunoglobulin light-chain amyloidosis (AL) and kindred evaluations with DNA sequencing of transthyretin (TTR) and gelsolin (GSN). Our study included 8 cases of AL-type amyloidosis, 11 cases of TTR amyloidosis (3 Val30Met, 2 Val32Ala, 2 Thr60Ala, 1Ala109Ser, 1 Phe64Leu, 1 Ala97Ser, 1 not sequenced), and 2 cases of gelsolin amyloidosis (1 Asp187Asn, 1 not sequenced). One TTR and one gelsolin amyloidosis patients with no specific mutation identified were diagnosed based on the genetic confirmation in their first degree relative. Congophilic proteins in the tissues of these 21 cases were laser microdissected, digested into tryptic peptides and analyzed utilizing liquid chromatography electrospray tandem mass spectrometry. Identified proteins were reviewed using bioinformatics tools with interpreters blinded to clinical information. Results Specific types of amyloid were accurately detected by LMD/MS in all cases (8 AL-type, 2 gelsolin, and 11 transthyretin). Incidental serum monoclonal proteins did not interfere with detection of TTR amyloidosis in two patients. Additionally, specific TTR mutations were identified in ten cases by LMD/MS. Serum amyloid P-component and apolipoprotein E proteins were commonly found among all cases. Conclusions Proteomic analysis of nerve tissue using LMD/MS distinguishes specific types of amyloid independent of clinical information. This new proteomic approach will enhance both diagnostic and research efforts in amyloidosis and other neurologic diseases.

Klein, Christopher J.; Vrana, Julie A.; Theis, Jason D.; Dyck, Peter J.; Dyck, P. James B.; Spinner, Robert J.; Mauermann, Michelle L; Bergen, H. Robert; Zeldenrust, Steven R.; Dogan, Ahmet

2011-01-01

327

Progress in Cancer Diagnosis With Ultrasound.  

National Technical Information Service (NTIS)

Despite successes in using ultrasound to characterize tissues at many sites in the body, the diagnosis of cancer, especially in the female breast, has remained challenging. Besides devising methods to analyze the data, there are difficulties with collecti...

J. M. Reid B. B. Goldberg P. M. Shankar F. Forsberg N. Bilgutay

2001-01-01

328

Model studies of thermal effects in ultrasound pregnancy investigation  

NASA Astrophysics Data System (ADS)

Certain scientific works published recently showed that harmful tissue heating could occur when applying Doppler diagnostic ultrasound on pregnant animals. Limited possibilities, which would verify the results of the animal experiments in clinical conditions, have led to computer modelling and simulations of such events. The presented embryonic models of ultrasound thermal effects are based on a modelling of ultrasound fields in a homogeneous medium and on a modelling of ultrasound fields in a simple biological system.

Orel, D.; Rozman, J.

2004-01-01

329

[Basics of ultrasound-guided nerve block].  

PubMed

The ultrasound waves (> 20 kHz) are high-frequency sound waves that are not audible to the human ear. As the ultrasound waves move through body tissues of different acoustic impedances, they are attenuated, reflected, or scattered. Reflected waves are transformed back into an electrical signal that is processed by the ultrasound machine to generate an image on the screen. In practice, an ultrasound probe emits and receives ultrasound waves, functioning both as a speaker and a microphone. The recent advance of ultrasonography has provided close-sectional images of the body in real time. Ultrasound imaging has been useful to visualize neural anatomical structures and the surrounding structures, and navigate the needle toward the target nerves. This review introduces the theories and practices of ultrasonography for the peripheral nerve blocks. PMID:18516881

Yamada, Masaki; Seo, Norimasa

2008-05-01

330

THREE-DIMENSIONAL COUPLED-OBJECT SEGMENTATION USING SYMMETRY AND TISSUE TYPE INFORMATION  

PubMed Central

This paper presents an automatic method for segmentation of brain structures using their symmetry and tissue type information. The proposed method generates segmented structures that have homogenous tissues. It benefits from general symmetry of the brain structures in the two hemispheres. It also benefits from the tissue regions generated by fuzzy c-means clustering. All in all, the proposed method can be described as a dynamic knowledge-based method that eliminates the need for statistical shape models of the structures while generating accurate segmentation results. The proposed approach is implemented in MATLAB and tested on the Internet Brain Segmentation Repository (IBSR) datasets. To this end, it is applied to the segmentation of caudate and ventricles three-dimensionally in magnetic resonance images (MRI) of the brain. Impacts of each of the steps of the proposed approach are demonstrated through experiments. It is shown that the proposed method generates accurate segmentation results that are insensitive to initialization and parameter selection. The proposed method is compared to four previous methods illustrating advantages and limitations of each method.

Bahmanbijari, Payam; Akhondi-Asl, Alireza; Soltanian-Zadeh, Hamid

2010-01-01

331

Tissue Stretch Decreases Soluble TGF-?1 and Type-1 Procollagen in Mouse Subcutaneous Connective Tissue: Evidence From Ex Vivo and In Vivo Models  

PubMed Central

Transforming growth factor beta 1 (TGF-?1) plays a key role in connective tissue remodeling, scarring, and fibrosis. The effects of mechanical forces on TGF-?1 and collagen deposition are not well understood. We tested the hypothesis that brief (10 min) static tissue stretch attenuates TGF-?1-mediated new collagen deposition in response to injury. We used two different models: (1) an ex vivo model in which excised mouse subcutaneous tissue (N = 44 animals) was kept in organ culture for 4 days and either stretched (20% strain for 10 min 1 day after excision) or not stretched; culture media was assayed by ELISA for TGF-?1; (2) an in vivo model in which mice (N = 22 animals) underwent unilateral subcutaneous microsurgical injury on the back, then were randomized to stretch (20–30% strain for 10 min twice a day for 7 days) or no stretch; subcutaneous tissues of the back were immunohistochemically stained for Type-1 procollagen. In the ex vivo model, TGF-?1 protein was lower in stretched versus non-stretched tissue (repeated measures ANOVA, P < 0.01). In the in vivo model, microinjury resulted in a significant increase in Type-1 procollagen in the absence of stretch (P < 0.001), but not in the presence of stretch (P = 0.21). Thus, brief tissue stretch attenuated the increase in both soluble TGF-?1 (ex vivo) and Type-1 procollagen (in vivo) following tissue injury. These results have potential relevance to the mechanisms of treatments applying brief mechanical stretch to tissues (e.g., physical therapy, respiratory therapy, mechanical ventilation, massage, yoga, acupuncture).

Bouffard, Nicole A.; Cutroneo, Kenneth R.; Badger, Gary J.; White, Sheryl L.; Buttolph, Thomas R.; Ehrlich, H. Paul; Stevens-Tuttle, Debbie; Langevin, Helene M.

2011-01-01

332

Behavior of Propagation and Heating Due to Absorption of Ultrasound in Medium  

Microsoft Academic Search

Recently, ultrasound waves have been put to practical use not only in diagnostic equipment but also in thermotherapy that uses the effect of ultrasound waves in a living body. The analysis of temperature rise due to the absorption of ultrasound in a soft tissue medium is an important analyzing object for the clarification of the effect of ultrasound waves in

Chiaki Yamaya; Hiroshi Inoue

2006-01-01

333

Bacillus anthracis oedema toxin as a cause of tissue necrosis and cell type-specific cytotoxicity.  

PubMed

Oedema factor (OF) and protective antigen (PA) are secreted by Bacillus anthracis, and their binary combination yields oedema toxin (OT). Following PA-mediated delivery to the cytosol, OF functions as an adenylate cyclase generating high levels of cAMP. To assess OT as a possible cause of tissue damage and cell death, a novel approach was developed, which utilized a developing zebrafish embryo model to study toxin activity. Zebrafish embryos incubated with OT exhibited marked necrosis of the liver, cranium and gastrointestinal tract, as well as reduced swim bladder inflation. The OT-treated embryos survived after all stages of development but succumbed to the toxin within 7 days. Additional analysis of specific cell lines, including macrophage and non-macrophage, showed OT-induced cell death is cell type-specific. There was no discernible correlation between levels of OF-generated cAMP and cell death. Depending on the type of cell analysed, cell death could be detected in low levels of cAMP, and, conversely, cell survival was observed in one cell line in which high levels of cAMP were found following treatment with OT. Collectively, these data suggest OT is cytotoxic in a cell-dependent manner and may contribute to disease through direct cell killing leading to tissue necrosis. PMID:16008581

Voth, Daniel E; Hamm, Elaine E; Nguyen, Lan G; Tucker, Amy E; Salles, Isabelle I; Ortiz-Leduc, William; Ballard, Jimmy D

2005-08-01

334

An essential role for TH2-type responses in limiting acute tissue damage during experimental helminth infection  

Microsoft Academic Search

Helminths induce potent T helper 2 (TH2)-type immune responses that can mediate worm expulsion, but the role of this response in controlling the acute tissue damage caused by migrating multicellular parasites through vital tissues remains uncertain. We used a helminth infection model in which parasitic nematode larvae migrate transiently through the lung, resulting in hemorrhage and inflammation. We found that

Fei Chen; Zhugong Liu; Wenhui Wu; Cristina Rozo; Scott Bowdridge; Ariel Millman; Nico Van Rooijen; Joseph F Urban; Thomas A Wynn; William C Gause

2012-01-01

335

Ultrasound Annual, 1984  

SciTech Connect

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

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

1984-01-01

336

Three-dimensional ultrasonic parametric and tissue-property imaging for tissue evaluation, treatment planning, therapy guidance, and efficacy assessment  

NASA Astrophysics Data System (ADS)

Two- and three-dimensional depictions of ultrasound echo signal data have potential for helping to detect and diagnose disease and to plan and monitor therapy. The utilization of very-high-frequency ultrasound and spectrum analysis of radio- frequency echo signals extends the capabilities of ultrasonic imaging for these purposes. Images generated using these techniques can present tissue architecture with exquisite resolution and can provide information on underlying properties of scatterers in the tissue. Changes in properties over time can be used to monitor disease progression or response to therapy. Relating tissue echo-signal parameters obtained from unknown tissue to database values of known tissue types can provide means of characterizing tissue for the purposes of detection or diagnosis and treatment planning. These potential applications are illustrated using examples from plaque, ophthalmic, skin, and prostate studies.

Feleppa, Ernest J.; Liu, Tian; Lizzi, Frederick L.; Kalisz, Andrew; Silverman, Ronald H.; Sigel, Bernard; Fair, William R.

2000-04-01

337

Medical Ultrasound Image Deconvolution  

NASA Astrophysics Data System (ADS)

In medical pulse-echo ultrasound imaging, a constant sound speed of 1,540 m/s in soft tissues is assumed. When the actual speed is different the mismatch can lead to image distortions. Even if the assumed speed is correct, ultrasound images can be difficult to interpret due to image blurring and the presence of speckle. However, this can be improved by non-blind deconvolution if the point-spread function (PSF) is known. In clinical applications a sufficiently accurate estimate of the PSF is difficult to obtain because of the unknown properties (including speed of sound) of soft tissues. In this paper, we address two topics: first, we explore the sensitivity of our deconvolution algorithm to variations in the speed of sound in the tissue; second, we extend our deconvolution algorithm to enable it to adapt to (and estimate) an unknown sound speed. In the first topic, the results reveal that the deconvolution output is sufficiently sensitive to the accuracy of the sound speed that the speed itself can be estimated using deconvolution. However, qualitative assessment suggests that we may not need the exact speed of sound for successful deconvolution so long as the assumed speed does not deviate significantly from the true value. In the second topic, the goal is gradually to adapt the assumed sound speed to improve the deconvolution and eventually estimate the true sound speed. We tested our algorithm with in vitro phantoms where the estimation error was found to be +0.01 ± 0.60% (mean ± standard deviation). In addition to the speed estimation itself, our method has also proved capable of producing better restoration of the ultrasound images than deconvolution by an assumed speed of 1,540 m/s when this assumption is significantly in error.

Shin, H.-C.; Prager, R. W.; Gomersall, H.; Kingsbury, N.; Treece, G. M.; Gee, A. H.

338

Prenatal ultrasound and histological diagnosis of fetal nasal glioma (heterotopic central nervous system tissue): report of a new case and review of the literature  

Microsoft Academic Search

Introduction  Nasal glioma is a rare, benign congenital midline facial lesion.\\u000a \\u000a \\u000a \\u000a Materials and methods  Prenatal ultrasound diagnosis performed at 2nd trimester of pregnancy revealed a right-sided mass at the level of the fetal\\u000a face extending from the right internal canthus to the nasal bridge.\\u000a \\u000a \\u000a \\u000a \\u000a Conclusion  Differential diagnosis of facial mass in the fetus represents a critical issue because is essential in guiding the

Gabriele Tonni; Mario Lituania; Maria Paola Bonasoni; Claudio De Felice

2011-01-01

339

Cell-type-specific expression pattern of ceramide synthase 2 protein in mouse tissues.  

PubMed

Ceramide synthase 2 (CerS2) catalyzes the synthesis of dihydroceramides from dihydrosphingosine and very long fatty acyl (C22-C24)-CoAs. CerS2-deficient (gene trap) mice were reported to exhibit myelin and behavioral abnormalities, associated with the expression of CerS2 in oligodendrocytes and neurons based on expression of lacZ reporter cDNA instead of the cers2 gene in these mice. In order to clarify the cell-type-specific expression of CerS2 protein, we have raised antibodies that specifically recognize the glycosylated and non-glycosylated CerS2 protein in wild-type but not in CerS2-deficient mouse tissues. In early postnatal, juvenile and adult mouse brain, the new antibodies detect CerS2 protein only in oligodendrocytes but not in neurons, suggesting that the gene trap vector in CerS2-deficient mice led to ectopic expression of the lacZ reporter gene in neurons. In liver, the CerS2 protein is expressed in hepatocytes but not in Ito cells or Kupffer cells. We conclude that the behavioral abnormalities observed in CerS2-deficient mice originate primarily in oligodendrocytes and not in neurons. The identification of specific cell types in which CerS2 protein is expressed is prerequisite to further mechanistic characterization of phenotypic abnormalities exhibited by CerS2-deficient mice. The amount of CerS2 protein detected in different tissues by immunoblot analyses does not strictly correspond to the activity of the CerS2 enzyme. Disproportional results are likely due to post-translational regulation of the CerS2 protein. PMID:23591958

Kremser, Christiane; Klemm, Anna-Lena; van Uelft, Martina; Imgrund, Silke; Ginkel, Christina; Hartmann, Dieter; Willecke, Klaus

2013-04-17

340

IL-1 antagonism reduces hyperglycemia and tissue inflammation in the type 2 diabetic GK rat  

PubMed Central

Recent studies suggest an inflammatory process, characterized by local cytokine/chemokine production and immune cell infiltration, regulates islet dysfunction and insulin resistance in type 2 diabetes. However, the factor initiating this inflammatory response is not known. Here, we characterized tissue inflammation in the type 2 diabetic GK rat with a focus on the pancreatic islet and investigated a role for IL-1. GK rat islets, previously characterized by increased macrophage infiltration, displayed increased expression of several inflammatory markers including IL-1?. In the periphery, increased expression of IL-1? was observed primarily in the liver. Specific blockade of IL-1 activity by the IL-1 receptor antagonist (IL-1Ra) reduced the release of inflammatory cytokines/chemokines from GK islets in vitro and from mouse islets exposed to metabolic stress. Islets from mice deficient in IL-1? or MyD88 challenged with glucose and palmitate in vitro also produced significantly less IL-6 and chemokines. In vivo, treatment of GK rats with IL-1Ra decreased hyperglycemia, reduced the proinsulin/insulin ratio, and improved insulin sensitivity. In addition, islet-derived proinflammatory cytokines/chemokines (IL-1?, IL-6, TNF?, KC, MCP-1, and MIP-1?) and islet CD68+, MHC II+, and CD53+ immune cell infiltration were reduced by IL-1Ra treatment. Treated GK rats also exhibited fewer markers of inflammation in the liver. We conclude that elevated islet IL-1? activity in the GK rat promotes cytokine and chemokine expression, leading to the recruitment of innate immune cells. Rather than being directly cytotoxic, IL-1? may drive tissue inflammation that impacts on both ? cell functional mass and insulin sensitivity in type 2 diabetes.

Ehses, J. A.; Lacraz, G.; Giroix, M.-H.; Schmidlin, F.; Coulaud, J.; Kassis, N.; Irminger, J.-C.; Kergoat, M.; Portha, B.; Homo-Delarche, F.; Donath, M. Y.

2009-01-01

341

Cryopreservation and in vitro culture of primary cell types from lung tissue of a stranded pygmy sperm whale (Kogia breviceps)?  

PubMed Central

Current models for in vitro studies of tissue function and physiology, including responses to hypoxia or environmental toxins, are limited and rely heavily on standard 2-dimensional (2-D) cultures with immortalized murine or human cell lines. To develop a new more powerful model system, we have pursued methods to establish and expand cultures of primary lung cell types and reconstituted tissues from marine mammals. What little is known about the physiology of the deep-sea diving pygmy sperm whale (PSW), Kogia breviceps, comes primarily from stranding events that occur along the coast of the southeastern United States. Thus, development of a method for preserving live tissues and retrieving live cells from deceased stranded individuals was initiated. This report documents successful cryopreservation of PSW lung tissue. We established in vitro cultures of primary lung cell types from tissue fragments that had been cryopreserved several months earlier at the stranding event. Dissociation of cryopreserved lung tissues readily provides a variety of primary cell types that, to varying degrees, can be expanded and further studied/manipulated in cell culture. In addition, PSW-specific molecular markers have been developed that permitted the monitoring of fibroblast, alveolar type II, and vascular endothelial cell types. Reconstitution of 3-D cultures of lung tissues with these cell types is now underway. This novel system may facilitate the development of rare or disease-specific lung tissue models (e.g., to test causes of PSW stranding events and lead to improved treatments for pulmonary hypertension or reperfusion injury in humans). Also, the establishment of a “living” tissue bank biorepository for rare/endangered species could serve multiple purposes as surrogates for freshly isolated samples.

Mancia, Annalaura; Spyropoulos, Demetri D.; McFee, Wayne E.; Newton, Danforth A.; Baatz, John E.

2011-01-01

342

Cryopreservation and in vitro culture of primary cell types from lung tissue of a stranded pygmy sperm whale (Kogia breviceps).  

PubMed

Current models for in vitro studies of tissue function and physiology, including responses to hypoxia or environmental toxins, are limited and rely heavily on standard 2-dimensional (2-D) cultures with immortalized murine or human cell lines. To develop a new more powerful model system, we have pursued methods to establish and expand cultures of primary lung cell types and reconstituted tissues from marine mammals. What little is known about the physiology of the deep-sea diving pygmy sperm whale (PSW), Kogia breviceps, comes primarily from stranding events that occur along the coast of the southeastern United States. Thus, development of a method for preserving live tissues and retrieving live cells from deceased stranded individuals was initiated. This report documents successful cryopreservation of PSW lung tissue. We established in vitro cultures of primary lung cell types from tissue fragments that had been cryopreserved several months earlier at the stranding event. Dissociation of cryopreserved lung tissues readily provides a variety of primary cell types that, to varying degrees, can be expanded and further studied/manipulated in cell culture. In addition, PSW-specific molecular markers have been developed that permitted the monitoring of fibroblast, alveolar type II, and vascular endothelial cell types. Reconstitution of 3-D cultures of lung tissues with these cell types is now underway. This novel system may facilitate the development of rare or disease-specific lung tissue models (e.g., to test causes of PSW stranding events and lead to improved treatments for pulmonary hypertension or reperfusion injury in humans). Also, the establishment of a "living" tissue bank biorepository for rare/endangered species could serve multiple purposes as surrogates for freshly isolated samples. PMID:21501697

Annalaura Mancia; Spyropoulos, Demetri D; McFee, Wayne E; Newton, Danforth A; Baatz, John E

2011-04-09

343

Comparison of rootMUSIC and discrete wavelet transform analysis of Doppler ultrasound blood flow waveforms to detect microvascular abnormalities in type I diabetes.  

PubMed

The earliest signs of cardiovascular disease occur in microcirculations. Changes to mechanical and structural properties of these small resistive vessels alter the impedance to flow, subsequent reflected waves, and consequently, flow waveform morphology. In this paper, we compare two frequency analysis techniques: 1) rootMUSIC and 2) the discrete wavelet transform (DWT) to extract features of flow velocity waveform morphology captured using Doppler ultrasound from the ophthalmic artery (OA) in 30 controls and 38 age and sex matched Type I diabetics. Conventional techniques for characterizing Doppler velocity waveforms, such as mean velocity, resistive index, and pulsatility index, revealed no significant differences between the groups. However, rootMUSIC and the DWT provided highly correlated results with the spectral content in bands 2-7 (30-0.8 Hz) significantly elevated in the diabetic group (p < 0.05). The spectral distinction between the groups may be attributable to manifestations of underlying pathophysiological processes in vascular impedance and consequent wave reflections, with bands 5 and 7 related to age. Spectral descriptors of OA blood velocity waveforms are better indicators of preclinical microvascular abnormalities in Type I diabetes than conventional measures. Although highly correlated DWT proved slightly more discriminatory than rootMUSIC and has the advantage of extending to subheart rate frequencies, which may be of interest. PMID:21138796

Agnew, Christina Elizabeth; McCann, A J; Lockhart, C J; Hamilton, P K; McVeigh, G E; McGivern, R C

2010-12-06

344

Evaluation of transfection efficiency in skeletal muscle using nano/microbubbles and ultrasound.  

PubMed

Recent studies have revealed that ultrasound contrast agents with low-intensity ultrasound, namely, sonoporation, can noninvasively deliver therapeutic molecules into target sites. However, the efficiency of molecular delivery is relatively low and the methodology requires optimization. Here, we investigated three types of nano/microbubbles (NMBs)-human albumin shell bubbles, lipid bubbles and acoustic liposomes-to evaluate the efficiency of gene expression in skeletal muscle as a function of their physicochemical properties and the number of bubbles in solution. We found that acoustic liposomes showed the highest transfection and gene expression efficiency among the three types of NMBs under ultrasound-optimized conditions. Liposome transfection efficiency increased with bubble volume concentration; however, neither bubble volume concentration nor their physicochemical properties were related to the tissue damage detected in the skeletal muscle, which was primarily caused by needle injection. PMID:20620706

Kodama, Tetsuya; Aoi, Atsuko; Watanabe, Yukiko; Horie, Sachiko; Kodama, Mizuho; Li, Li; Chen, Rui; Teramoto, Noriyoshi; Morikawa, Hidehiro; Mori, Shiro; Fukumoto, Manabu

2010-07-01

345

A multi-tissue type genome-scale metabolic network for analysis of whole-body systems physiology  

PubMed Central

Background Genome-scale metabolic reconstructions provide a biologically meaningful mechanistic basis for the genotype-phenotype relationship. The global human metabolic network, termed Recon 1, has recently been reconstructed allowing the systems analysis of human metabolic physiology and pathology. Utilizing high-throughput data, Recon 1 has recently been tailored to different cells and tissues, including the liver, kidney, brain, and alveolar macrophage. These models have shown utility in the study of systems medicine. However, no integrated analysis between human tissues has been done. Results To describe tissue-specific functions, Recon 1 was tailored to describe metabolism in three human cells: adipocytes, hepatocytes, and myocytes. These cell-specific networks were manually curated and validated based on known cellular metabolic functions. To study intercellular interactions, a novel multi-tissue type modeling approach was developed to integrate the metabolic functions for the three cell types, and subsequently used to simulate known integrated metabolic cycles. In addition, the multi-tissue model was used to study diabetes: a pathology with systemic properties. High-throughput data was integrated with the network to determine differential metabolic activity between obese and type II obese gastric bypass patients in a whole-body context. Conclusion The multi-tissue type modeling approach presented provides a platform to study integrated metabolic states. As more cell and tissue-specific models are released, it is critical to develop a framework in which to study their interdependencies.

2011-01-01

346

Quantitative multispectral analysis following fluorescent tissue transplant for visualization of cell origins, types, and interactions.  

PubMed

With the desire to understand the contributions of multiple cellular elements to the development of a complex tissue; such as the numerous cell types that participate in regenerating tissue, tumor formation, or vasculogenesis, we devised a multi-colored cellular transplant model of tumor development in which cell populations originate from different fluorescently colored reporter gene mice and are transplanted, engrafted or injected in and around a developing tumor. These colored cells are then recruited and incorporated into the tumor stroma. In order to quantitatively assess bone marrow derived tumor stromal cells, we transplanted GFP expressing transgenic whole bone marrow into lethally irradiated RFP expressing mice as approved by IACUC. 0ovarian tumors that were orthotopically injected into the transplanted mice were excised 6-8 weeks post engraftment and analyzed for bone marrow marker of origin (GFP) as well as antibody markers to detect tumor associated stroma using multispectral imaging techniques. We then adapted a methodology we call MIMicc- Multispectral Interrogation of Multiplexed cellular compositions, using multispectral unmixing of fluoroprobes to quantitatively assess which labeled cell came from which starting populations (based on original reporter gene labels), and as our ability to unmix 4, 5, 6 or more spectra per slide increases, we've added additional immunohistochemistry associated with cell lineages or differentiation to increase precision. Utilizing software to detect co-localized multiplexed-fluorescent signals, tumor stromal populations can be traced, enumerated and characterized based on marker staining.(1.) PMID:24084599

Spaeth, Erika L; Booth, Christopher M; Marini, Frank C

2013-09-22

347

Measurement of human tissue-type plasminogen activator by a two-site immunoradiometric assay  

SciTech Connect

A two-site immunoradiometric assay for human extrinsic (tissue-type) plasminogen activator was developed by using rabbit antibodies raised against plasminogen activator purified from human melanoma cell culture fluid. Samples of 100 ..mu..l containing 1 to 100 ng/ml plasminogen activator were incubated in the wells of polyvinyl chloride microtiter plates coated with antibody. The amount of bound extrinsic plasminogen activator was quantitated by the subsequent binding of /sup 125/I-labeled affinospecific antibody. The mean level of plasma samples taken at rest was 6.6 +/- 2.9 ng/ml (n = 54). This level increased approximately threefold by exhaustive physical exercise, venous occlusion, or infusion of DDAVP. Extrinsic plasminogen activator in plasma is composed of a fibrin-adsorbable and active component (1.9 +/- 1.1 ng/ml, n = 54, in resting conditions) and an inactive component that does not bind to a fibrin clot (probably extrinsic plasminogen activator-proteinase inhibitor complexes). The fibrin-adsorbable fraction increased approximately fivefold to eightfold after physical exercise, venous occlusion, or DDAVP injections. Potential applications of the immunoradiometric assay are illustrated by the measurement of extrinsic plasminogen activator in different tissue extracts, body fluids, and cell culture fluids and in oocyte translation products after injection with mRNA for plasminogen activator.

Rijken, D.C. (Univ. of Leuven, Belgium); Juhan-Vague, I.; De Cock, F.; Collen, D.

1983-02-01

348

Tyrosinaemia type I--de novo mutation in liver tissue suppressing an inborn splicing defect.  

PubMed

Many patients with tyrosinaemia type 1 have a mosaic pattern of fumarylacetoacetase (FAH) immunopositive or immunonegative nodules in liver tissue. This phenomenon has been explained by a spontaneous reversion of the mutation in one allele to a normal genotype, but only a few nodules have been examined. We now report on a Norwegian patient, compound heterozygous for the mutations IVS12g(+5)-->a and G(1009-->)A, with liver mosaicism, but with an immunopositive nodule in which both primary mutations were intact. In the immunopositive hepatocytes of this nodule, genetic analyses showed a new mutation, C(1061-->)A, 6 bp upstream of the primary mutation IVS12g(+5)-->a in the FAH gene. The splicing defect caused by the primary mutation is most likely suppressed by the new mutation due to improvement of the splicing site. In the same liver we demonstrate another nodule of regenerating immunopositive tissue due to reversion of one of the primary mutations to a normal genotype. Together with the original cells this makes a triple mosaicism of hepatocytes with one, two or three point mutations in the FAH gene. PMID:15759101

Bliksrud, Y T; Brodtkorb, E; Andresen, P A; van den Berg, I E T; Kvittingen, E A

2005-03-10

349

Tissue-specific Positive Feedback Requirements for Production of Type I Interferon following Virus Infection*  

PubMed Central

Type I interferon (IFN) is synthesized by most nucleated cells following viral infection. Robust IFN production in cell culture requires positive feedback expression of inducible signaling components, such as the transcription factor IRF7. However, the role of positive feedback and IRF7 in vivo may be more complex. We found that IFN produced locally in the respiratory tract of influenza virus-infected mice displayed characteristics of positive feedback, including Stat1-dependent induction of IRF7 and IFN gene expression. IRF7 expression was similarly stimulus-dependent in most tissues. However, lymphoid tissue constitutively expressed high levels of IRF7 in the absence of induction or positive feedback, and this expression was largely confined to plasmacytoid dendritic cells (DC). These cells rapidly produced large quantities of multiple IFN? species following viral infection without positive feedback, whereas other hematopoietic cells, including other DC subtypes, expressed little IRF7 and were poor IFN producers in the absence of positive feedback. These data reveal a dual mechanism for the regulation of IFN production by differential expression of IRF7, involving positive feedback at local sites of infection combined with robust systemic production by IRF7-expressing plasmacytoid DC.

Prakash, Arun; Smith, Eric; Lee, Chien-kuo; Levy, David E.

2005-01-01

350

Characterization of tissue plasminogen activator binding proteins isolated from endothelial cells and other cell types  

SciTech Connect

Human tissue plasminogen activator (t-PA) was shown to bind specifically to human osteosarcoma cells (HOS), and human epidermoid carcinoma cells (A-431 cells). Crosslinking studies with DTSSP demonstrated high molecular weight complexes (130,000) between {sup 125}I-t-PA and cell membrane protein on human umbilical vein endothelial cells (HUVEC), HOS, and A-431 cells. A 48-65,000 molecular weight complex was demonstrated after crosslinking t-PA peptide (res. 7-20) to cells. Ligand blotting of cell lysates which had been passed over a t-PA affinity column revealed binding of t-PA to 54,000 and 95,000 molecular weight proteins. Several t-PA binding proteins were identified in immunopurified cell lysates, including tubulin beta chain, plasminogen activator inhibitor type 1 and single chain urokinase.

Beebe, D.P.; Wood, L.L.; Moos, M. (Food and Drug Administration, Bethesda, MD (USA))

1990-07-15

351

Intestinal inflammation induces genotoxicity to extraintestinal tissues and cell types in mice  

PubMed Central

Chronic intestinal inflammation leads to increased risk of colorectal and small intestinal cancers, and is also associated with extraintestinal manifestations such as lymphomas, other solid cancers, and autoimmune disorders. We have previously found that acute and chronic intestinal inflammation causes DNA damage to circulating peripheral leukocytes, manifesting a systemic effect in genetic and chemically-induced models of intestinal inflammation. This study addresses the scope of tissue targets and genotoxic damage induced by inflammation-associated genotoxicity. Using several experimental models of intestinal inflammation, we analyzed various types of DNA damage in leukocyte subpopulations of the blood, spleen, mesenteric and peripheral lymph nodes; and, in intestinal epithelial cells, hepatocytes, and the brain. Genotoxicity in the form of DNA single and double stranded breaks accompanied by oxidative base damage was found in leukocyte subpopulations of the blood, diverse lymphoid organs, intestinal epithelial cells, and hepatocytes. The brain did not demonstrate significant levels of DNA double strand breaks as measured by ?-H2AX immunostaining. CD4+ and CD8+ T-cells were most sensitive to DNA damage versus other cell types in the peripheral blood. In vivo measurements and in vitro modeling suggested that genotoxicity was induced by increased levels of systemically circulating proinflammatory cytokines. Moreover, genotoxicity involved increased damage rather than reduced repair, since it not associated with decreased expression of the DNA double-strand break recognition and repair protein, ataxia telangiectasia mutated (ATM). These findings suggest that levels of intestinal inflammation contribute to the remote tissue burden of genotoxicity, with potential effects on non-intestinal diseases and cancer.

Westbrook, Aya M.; Wei, Bo; Braun, Jonathan; Schiestl, Robert H.

2011-01-01

352

Difference in kinetic properties between hexokinase type I isoenzymes from various rat tissues with reference to the effect of a thiol inhibitor (Short Communication)  

PubMed Central

Hexokinase isoenzyme type I was purified from various rat tissues, and was subjected to kinetic studies in the presence or the absence of p-chloromercuribenzenesulphonate. The mode of the inhibition by the thiol inhibitor was different for the type I isoenzymes obtained from different tissues, suggesting that the type I isoenzymes from different tissues were not identical proteins.

Kamikashi, T.; Kizaki, H.; Murakami, K.; Ishibashi, S.

1974-01-01

353

Importance of extensive staging in patients with mucosa-associated lymphoid tissue (MALT)-type lymphoma  

PubMed Central

Lymphoma of the mucosa-associated lymphoid tissue (MALT) type usually arises in MALT acquired through chronic antigenic stimulation triggered by persistent infection and/or autoimmune processes. Due to specific ligand–receptor interactions between lymphoid cells and high-endothelial venules of MALT, both normal and neoplastic lymphoid cells display a pronounced homing tendency to MALT throughout the body. In the case of neoplastic disease these homing properties may be responsible for lymphoma dissemination among various MALT-sites. According to this concept, we have standardized staging procedures in all patients diagnosed with MALT-type lymphoma. All patients with MALT-type lymphoma underwent standardized staging procedures before treatment. Staging included ophthalmologic examination, otolaryngologic investigation, gastroscopy with multiple biopsies, endosonography of the upper gastrointestinal tract, enteroclysis, colonoscopy, computed tomography of thorax and abdomen and bone marrow biopsy. Biopsy was performed in all lesions suggestive for lymphomatous involvement, and evaluation of all biopsy specimens was performed by a reference pathologist. 35 consecutive patients with histologically verified MALT-type lymphoma were admitted to our department. Twenty-four patients (68%) had primary involvement of the stomach, five (15%) had lymphoma of the ocular adnexa, three (8.5%) had lymphoma of the parotid, and three (8,5%) of the lung. Lymph-node involvement corresponding to stage EII disease was found in 13 patients (37%), only one patient with primary gastric lymphoma had local and supradiaphragmatic lymph-node involvement (stage EIII). Bone marrow biopsies were negative in all patients. Overall, eight of 35 patients (23%) had simultaneous biopsy-proven involvement of two MALT-sites: one patient each had lymphoma of parotid and lacrimal gland, conjunctiva and hypopharynx, conjunctiva and skin, lacrimal gland and lung, stomach and colon, and stomach and lung. The remaining two patients had bilateral parotideal lymphoma. Staging work-up was negative for lymph-node involvement in all of these eight patients. The importance of extensive staging in MALT-type lymphoma is emphasized by the demonstration of multiorgan involvement in almost a quarter of patients. In addition, our data suggest that extra-gastrointestinal MALT-type lymphoma more frequently occurs simultaneously at different anatomic sites than MALT-type lymphoma involving the GI-tract. © 2000 Cancer Research Campaign

Raderer, M; Vorbeck, F; Formanek, M; Osterreicher, C; Valencak, J; Penz, M; Kornek, G; Hamilton, G; Dragosics, B; Chott, A

2000-01-01

354

The Application of Three–Dimensional Contrast–Enhanced Ultrasound to Measure Volume of Affected Tissue after HIFU Treatment for Localized Prostate Cancer  

Microsoft Academic Search

Introduction: Adequate monitoring of volume and location of affected tissue might provide helpful information when performing localized ablative therapy for prostate cancer. We hypothesize that the change in blood flow patterns after therapy in comparison to the blood flow pattern prior to therapy can be used to locate and quantify the amount of affected tissue due to the therapy. We

J. P. Michiel Sedelaar; René G. Aarnink; Geert J. L. H. van Leenders; Harrie P. Beerlage; Frans M. J. Debruyne; Hessel Wijkstra; Jean J. M. C. H. de la Rosette

2000-01-01

355

Exercise and Type 2 Diabetes Mellitus: Changes in Tissue-specific Fat Distribution and Cardiac Function.  

PubMed

Purpose: To prospectively assess the effects of an exercise intervention on organ-specific fat accumulation and cardiac function in type 2 diabetes mellitus. Materials and Methods: Written informed consent was obtained from all participants, and the study protocol was approved by the medical ethics committee. The study followed 12 patients with type 2 diabetes mellitus (seven men; mean age, 46 years ± 2 [standard error]) before and after 6 months of moderate-intensity exercise, followed by a high-altitude trekking expedition with exercise of long duration. Abdominal, epicardial, and paracardial fat volume were measured by using magnetic resonance (MR) imaging. Cardiac function was quantified with cardiac MR, and images were analyzed by a researcher who was supervised by a senior researcher (4 and 21 years of respective experience in cardiac MR). Hepatic, myocardial, and intramyocellular triglyceride (TG) content relative to water were measured with proton MR spectroscopy at 1.5 and 7 T. Two-tailed paired t tests were used for statistical analysis. Results: Exercise reduced visceral abdominal fat volume from 348 mL ± 57 to 219 mL ± 33 (P < .01), and subcutaneous abdominal fat volume remained unchanged (P = .9). Exercise decreased hepatic TG content from 6.8% ± 2.3 to 4.6% ± 1.6 (P < .01) and paracardial fat volume from 4.6 mL ± 0.9 to 3.7 mL ± 0.8 (P = .02). Exercise did not change epicardial fat volume (P = .9), myocardial TG content (P = .9), intramyocellular lipid content (P = .3), or cardiac function (P = .5). Conclusion: A 6-month exercise intervention in type 2 diabetes mellitus decreased hepatic TG content and visceral abdominal and paracardial fat volume, which are associated with increased cardiovascular risk, but cardiac function was unaffected. Tissue-specific exercise-induced changes in body fat distribution in type 2 diabetes mellitus were demonstrated in this study. © RSNA, 2013. PMID:23801768

Jonker, Jacqueline T; de Mol, Pieter; de Vries, Suzanna T; Widya, Ralph L; Hammer, Sebastiaan; van Schinkel, Linda D; van der Meer, Rutger W; Gans, Rijk O B; Webb, Andrew G; Kan, Hermien E; de Koning, Eelco J P; Bilo, Henk J G; Lamb, Hildo J

2013-06-25

356

Adipose tissue macrophages in the development of obesity-induced inflammation, insulin resistance and type 2 Diabetes.  

PubMed

It has been increasingly accepted that chronic subacute inflammation plays an important role in the development of insulin resistance and type 2 Diabetes in animals and humans. Particularly supporting this is that suppression of systemic inflammation in type 2 Diabetes improves glycemic control; this also points to a new potential therapeutic target for the treatment of type 2 Diabetes. Recent studies strongly suggest that obesity-induced inflammation is mainly mediated by tissue resident immune cells, with particular attention being focused on adipose tissue macrophages (ATMs). This review delineates the current progress made in understanding obesity-induced inflammation and the roles ATMs play in this process. PMID:23397293

Lee, Jongsoon

2013-02-10

357

Differential modulation of the functionality of white adipose tissue of obese Zucker (fa/fa) rats by the type of protein and the amount and type of fat.  

PubMed

Recent evidence indicates that several metabolic abnormalities developed during obesity are associated with the presence of dysfunctional adipose tissue. Diet is a key factor that modulates several functions of adipose tissue; however, each nutrient in the diet produces specific changes. Thus, the aim of this work was to study the effect of the interaction of the type (coconut or soybean oil) and amount (5% or 10%) of fat with the type of dietary protein (casein or soy protein) on the functionality of white adipose tissue of Zucker (fa/fa) rats. The results showed that soybean oil reduced adipocyte size and decreased esterified saturated fatty acids in white adipose tissue. Excess dietary fat also modified the composition of esterified fatty acids in white adipose tissue, increased the secretion of saturated fatty acids to serum from white adipose tissue and reduced the process of fatty acids re-esterification. On the other hand, soy protein sensitized the activation of the hormone-sensitive lipase by increasing the phosphorylation of this enzyme (Ser 563) despite rats fed soy protein were normoglucagonemic, in contrast with rats fed casein that showed hyperglucagonemia but reduced hormone-sensitive lipase phosphorylation. Finally, in white adipose tissue, the interaction between the tested dietary components modulated the transcription/translation process of lipid and carbohydrate metabolism genes via the activity of the PERK-endoplasmic reticulum stress response. Therefore, our results showed that the type of protein and the type and amount of dietary fat selectively modify the activity of white adipose tissue, even in a genetic model of obesity. PMID:23773624

Díaz-Villaseñor, Andrea; Granados, Omar; González-Palacios, Berenice; Tovar-Palacio, Claudia; Torre-Villalvazo, Ivan; Olivares-García, Verónica; Torres, Nimbe; Tovar, Armando R

2013-06-14

358

Kinetic analysis of the interaction between plasminogen activator inhibitor-1 and tissue-type plasminogen activator.  

PubMed Central

The kinetics of inhibition of tissue-type plasminogen activator (t-PA) by the fast-acting plasminogen activator inhibitor-1 (PAI-1) was investigated in homogeneous (plasma) and heterogeneous (solid-phase fibrin) systems by using radioisotopic and spectrophotometric analysis. It is demonstrated that fibrin-bound t-PA is protected from inhibition by PAI-1, whereas t-PA in soluble phase is rapidly inhibited (K1 = 10(7) M-1.s-1) even in the presence of 2 microM-plasminogen. The inhibitor interferes with the binding of t-PA to fibrin in a competitive manner. As a consequence the Kd of t-PA for fibrin (1.2 +/- 0.4 nM) increases and the maximal velocity of plasminogen activation by fibrin-bound t-PA is not modified. From the plot of the apparent Kd versus the concentration of PAI-1 a Ki value of 1.3 +/- 0.3 nM was calculated. The quasi-similar values for the dissociation constants between fibrin and t-PA (Kd) and between PAI-1 and t-PA (Ki), as well as the competitive type of inhibition observed, indicate that the fibrinolytic activity of human plasma may be the result of an equilibrium distribution of t-PA between both the amount of fibrin generated and the concentration of circulating inhibitor. Images Fig. 2. Fig. 3.

Masson, C; Angles-Cano, E

1988-01-01

359

Angle-dependent ultrasonic detection and imaging of two types of brachytherapy seeds using singular spectrum analysis.  

PubMed

Brachytherapy to treat prostate cancer uses transrectal ultrasound to guide implantation of titanium-shelled radioactive seeds. Transperitoneal implantation allows errors in placement that cause suboptimal dosimetry. Conventional ultrasound cannot reliably image implanted seeds; therefore, seed misplacements cannot be corrected in the operating room. Previously, an algorithm based on singular spectrum analysis was shown to image palladium seeds better than B-mode ultrasound could. The algorithm is now applied to imaging an iodine seed in gel and in beef tissue as a function of seed angle relative to the incident ultrasound. Results indicate that both seed types are imaged reliably by the algorithm. PMID:19206692

Mamou, Jonathan; Ramachandran, Sarayu; Feleppa, Ernest J

2008-12-01

360

Angle-dependent ultrasonic detection and imaging of two types of brachytherapy seeds using singular spectrum analysis  

PubMed Central

Brachytherapy to treat prostate cancer uses transrectal ultrasound to guide implantation of titanium-shelled radioactive seeds. Transperitoneal implantation allows errors in placement that cause suboptimal dosimetry. Conventional ultrasound cannot reliably image implanted seeds; therefore, seed misplacements cannot be corrected in the operating room. Previously, an algorithm based on singular spectrum analysis was shown to image palladium seeds better than B-mode ultrasound could. The algorithm is now applied to imaging an iodine seed in gel and in beef tissue as a function of seed angle relative to the incident ultrasound. Results indicate that both seed types are imaged reliably by the algorithm.

Mamou, Jonathan; Ramachandran, Sarayu; Feleppa, Ernest J.

2008-01-01

361

High definition ultrasound imaging for battlefield medical applications  

SciTech Connect

A team has developed an improved resolution ultrasound system for low cost diagnostics. This paper describes the development of an ultrasound based imaging system capable of generating 3D images showing surface and subsurface tissue and bone structures. We include results of a comparative study between images obtained from X-Ray Computed Tomography (CT) and ultrasound. We found that the quality of ultrasound images compares favorably with those from CT. Volumetric and surface data extracted from these images were within 7% of the range between ultrasound and CT scans. We also include images of porcine abdominal scans from two different sets of animal trials.

Kwok, K.S.; Morimoto, A.K.; Kozlowski, D.M.; Krumm, J.C.; Dickey, F.M. [Sandia National Labs., Albuquerque, NM (United States); Rogers, B; Walsh, N. [Texas Univ. Health Science Center, San Antonio, TX (United States)

1996-06-23

362

Contrast-Enhanced Ultrasound Imaging of Prostate Cancer  

PubMed Central

Ultrasound imaging of the prostate is commonly used to assess the size of the gland and for needle placement during systematic biopsy. Ultrasound evaluation of prostate cancer is limited by difficulty in distinguishing benign from malignant tissue. Although Doppler techniques may provide some improvement in the detection of prostate cancer, targeted biopsy based on conventional ultrasound with Doppler is not sufficient to replace systematic biopsy. Contrast-enhanced ultrasound imaging techniques that employ microbubble contrast agents represent an innovative approach to imaging of the neovascularity associated with prostate cancer. This review describes the application of contrast-enhanced ultrasound to improve detection and assessment of prostate cancer.

Halpern, Ethan J

2006-01-01

363

Quantitative analysis of cyanogen bromide-cleaved peptides for the assessment of type I: type II collagen ratios in equine articular repair tissue.  

PubMed

Cyanogen bromide was used to solubilise and specifically fragment purified equine Type I and II collagen and equine articular surface repair tissue. The resultant peptides were separated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and quantified by densitometric scanning. Measurement of the relative amounts of the peptides alpha 2(I) CB3, 5 and alpha 1(II)CB10 provided an accurate method of establishing the ratio of Type I to Type II collagen in mixtures of purified equine collagens. The method was sensitive to 6% Type II collagen when the band areas were corrected for peptide molecular weight and the number of chains in the parent tropocollagen molecule which contain that particular peptide. Use of this technique showed that repair tissue in full thickness osteochondral defects in the dorso-distal margins of the intermediate carpal bones of ponies did not contain detectable amounts of Type II collagen 11 weeks after defect induction. PMID:8143659

Barr, A R; Duance, V C; Wotton, S F; Waterman, A E; Holt, P E

1994-01-01

364

Ultrasonic detection of photothermal interaction of lasers with tissue using a pulsed Doppler system  

NASA Astrophysics Data System (ADS)

Thermal therapy using various heating sources such as lasers or microwaves to destroy benign and malignant lesions has recently gained widespread acceptance. However, the accurate prediction of thermal damage in tissue according to theoretical or computer modeling is difficult and unreliable due to target variability with respect to physical properties, geometry, and blood perfusion. Thus, one of the major obstacles to application of thermal therapies has been the lack of a noninvasive, real-time method that could determine the extent and geometry of treated tissue. To evaluate the effects of laser heating on tissue, we have developed an analog-digital hybrid Doppler ultrasound system to measure the phase and amplitude of ultrasonic echoes returned from the heated tissue. The system consists of an eight-gate pulsed Doppler detector, a 16-channel 12-bit A/D converter, and a signal analysis and visualization software package. In vitro studies using canine liver showed two distinct types of modulation of the echoes along the ultrasound beam path during laser irradiation using an 810 nm diode laser. Type 1 signals showed a small and slow variation in amplitude and phase, and were attributed to tissue coagulation. Type 1 signals showed a small and slow variation in amplitude and phase, and were attributed to tissue coagulation. Type 2 signals showed large and rapid variations in amplitude and phase which usually appeared after tissue surface explosion and were indicative of tissue ablation. We hypothesize that the observed phase changes in type 1 signals are due to thermal effects within the tissue consistent with tissue expansion and contraction while the phase changes in type 2 signals are likely due to formation and motion of gas bubbles in the tissue. A further development of the Doppler ultrasound technique could lead to the generation of feedback information needed for monitoring and automatic control of thermal treatment using various heating modalities such as laser, high intensity focused ultrasound, microwaves, or radio frequency waves.

Ying, Hao; Azeemi, Aamer; Hartley, Craig J.; Motamedi, Massoud; Bell, Brent A.; Rastegar, Sohi; Sheppard, L. C.

1995-05-01

365

Discordant gene expression in skeletal muscle and adipose tissue of patients with type 2 diabetes: effect of interleukin-6 infusion  

Microsoft Academic Search

Aims\\/hypothesis  We compared metabolic gene expression in adipose tissue and skeletal muscle from patients with type 2 diabetes and from well-matched healthy control subjects. We hypothesised that gene expression would be discordantly regulated when comparing the two groups. Our secondary aim was to determine the effect of Interleukin-6 (IL6) infusion on circulating adipokines and on gene expression in human adipose tissue.

A. L. Carey; E. Wolsk Petersen; C. R. Bruce; R. J. Southgate; H. Pilegaard; J. A. Hawley; B. K. Pedersen; M. A. Febbraio

2006-01-01

366

Possible Mechanisms of Local Tissue Renin-Angiotensin System Activation in the Cardiorenal Metabolic Syndrome and Type 2 Diabetes Mellitus  

Microsoft Academic Search

The role of local tissue renin-angiotensin system (tRAS) activation in the cardiorenal metabolic syndrome (CRS) and type 2 diabetes mellitus (T2DM) is not well understood. To this point, we posit that early redox stress-mediated injury to tissues and organs via accumulation of excessive reactive oxygen species (ROS) and associated wound healing responses might serve as a paradigm to better understand

Melvin R. Hayden; Kurt M. Sowers; Lakshmi Pulakat; Tejaswini Joginpally; Bennett Krueger; Adam Whaley-Connell; James R. Sowers

2011-01-01

367

Different Types of Scaffolds for Reconstruction of the Urinary Tract by Tissue Engineering  

Microsoft Academic Search

Introduction: Tissue engineering is an important and expanding field in reconstructive surgery. The ideal biomaterial for urologic tissue engineering should be biodegradable and support autologous cell growth. We examined different scaffolds to select the ideal material for the reconstruction of the bladder wall by tissue engineering. Materials and Methods: We seeded mouse fibroblasts and human keratinocytes in a co-culture model

Bernhard Brehmer; Dorothea Rohrmann; Christoph Becker; Günther Rau; Gerhard Jakse

2007-01-01

368

Distribution of type D retrovirus sequences in tissues of macaques with simian acquired immune deficiency and retroperitoneal fibromatosis.  

PubMed

Horizontally acquired SAIDS retrovirus type 2 (SRV-2), a type D retrovirus related to the Mason-Pfizer monkey virus, has been associated with the simian acquired immunodeficiency syndrome (SAIDS) including retroperitoneal fibromatosis (RF) in several macaque species at two primate research centers. Virus specific gene sequences are present in lymphoid and RF tissues but not in muscle tissue of diseased macaques or in any tissues of uninfected normal monkeys. Serologic and restriction endonuclease mapping techniques have defined unique SRV-2 strains in the Celebes (SRV-2C) and rhesus (SRV-2R) macaques at the Oregon Regional Primate Center, SRV-2 is related to both MPMV and SAIDS type 1 retroviruses and it has no detectable molecular homology with the human AIDS retroviruses. PMID:3006332

Bryant, M L; Marx, P A; Shiigi, S M; Wilson, B J; McNulty, W P; Gardner, M B

1986-04-15

369

Characterization of the interaction in vivo of tissue-type plasminogen activator with liver cells  

SciTech Connect

The interaction in vivo of 125I-labeled tissue-type plasminogen activator (t-PA) with the rat liver and the various liver cell types was characterized. Intravenously injected 125I-t-PA was rapidly cleared from the plasma (t1/2 = 1 min), and 80% of the injected dose associated with the liver. After uptake, t-PA was rapidly degraded in the lysosomes. The interaction of 125I-t-PA with the liver could be inhibited by preinjection of the rats with ovalbumin or unlabeled t-PA. The intrahepatic recognition site(s) for t-PA were determined by subfractionation of the liver in parenchymal, endothelial, and Kupffer cells. It can be calculated that parenchymal cells are responsible for 54.5% of the interaction of t-PA with the liver, endothelial cells for 39.5%, and Kupffer cells for only 6%. The association of t-PA with parenchymal cells was not mediated by a carbohydrate-specific receptor and could only be inhibited by an excess of unlabeled t-PA, indicating involvement of a specific t-PA recognition site. The association of t-PA with endothelial cells could be inhibited 80% by the mannose-terminated glycoprotein ovalbumin, suggesting that the mannose receptor plays a major role in the recognition of t-PA by endothelial liver cells. An excess of unlabeled t-PA inhibited the association of 125I-t-PA to endothelial liver cells 95%, indicating that an additional specific t-PA recognition site may be responsible for 15% of the high affinity interaction of t-PA with this liver cell type. It is concluded that the uptake of t-PA by the liver is mainly mediated by two recognition systems: a specific t-PA site on parenchymal cells and the mannose receptor on endothelial liver cells. It is suggested that for the development of strategies to prolong the half-life of t-PA in the blood, the presence of both types of recognition systems has to be taken into account.

Kuiper, J.; Otter, M.; Rijken, D.C.; van Berkel, T.J.

1988-12-05

370

Butyrate stimulates tissue-type plasminogen-activator synthesis in cultured human endothelial cells.  

PubMed Central

Incubation of cultured human endothelial cells with 5 mM-dibutyryl cyclic AMP led to an approx. 2-fold increase in tissue-type plasminogen-activator (t-PA) production over a 24 h incubation period. The stimulating effect of dibutyryl cyclic AMP could be explained by the slow liberation of butyrate, as the effect could be reproduced by addition of free butyrate to the medium, but not by addition of 8-bromo cyclic AMP or forskolin, agents known to raise intracellular cyclic AMP levels. With butyrate, an accelerated accumulation of t-PA antigen in the conditioned medium (CM) was observed after a lag period of about 6 h. Increasing amounts of butyrate caused an increasingly stimulatory effect, reaching a plateau at 5 mM-butyrate. The relative enhancement of t-PA production in the presence of 5 mM-butyrate varied among different endothelial cell cultures from 6- to 25-fold in 24 h CM. Such an increase in t-PA production was observed with both arterial and venous endothelial cells. The butyrate-induced increases in t-PA production were accompanied by increased t-PA mRNA levels. Analysis of radiolabelled CM and cell extracts by SDS/polyacrylamide-gel electrophoresis indicated that the potent action of butyrate is probably restricted to a small number of proteins. The accumulation of plasminogen activator inhibitor type 1 (PAI-1) in CM from butyrate-treated cells varied only moderately. In our study of the relationship between structure and stimulatory activity, we found that a straight-chain C4 monocarboxylate structure with a methyl group at one end and a carboxy moiety at the other seems to be required for the optimal induction of t-PA in cultured endothelial cells. Images Fig. 2. Fig. 3. Fig. 5. Fig. 7.

Kooistra, T; van den Berg, J; Tons, A; Platenburg, G; Rijken, D C; van den Berg, E

1987-01-01

371

Tissue-type plasminogen activator is an extracellular mediator of Purkinje cell damage and altered gait.  

PubMed

Purkinje neurons are a sensitive and specialised cell type important for fine motor movement and coordination. Purkinje cell damage manifests as motor incoordination and ataxia - a prominent feature of many human disorders including spinocerebellar ataxia and Huntington's disease. A correlation between Purkinje degeneration and excess cerebellar levels of tissue-type plasminogen activator (tPA) has been observed in multiple genetically-distinct models of ataxia. Here we show that Purkinje loss in a mouse model of Huntington's disease also correlates with a 200% increase in cerebellar tPA activity. That elevated tPA levels arise in a variety of ataxia models suggests that tPA is a common mediator of Purkinje damage. To address the specific contribution of tPA to cerebellar dysfunction we studied the T4 mice line that overexpresses murine tPA in postnatal neurons through the Thy1.2 gene promoter, which directs preferential expression to Purkinje cells within the cerebellum. Here we show that T4 mice develop signs of cerebellar damage within 10weeks of birth including atrophy of Purkinje cell soma and dendrites, astrogliosis, reduced molecular layer volume and altered gait. In contrast, T4 mice displayed no evidence of microgliosis, nor any changes in interneuron density, nor alteration in the cerebellar granular neuron layer. Thus, excess tPA levels may be sufficient to cause targeted Purkinje cell degeneration and ataxia. We propose that elevated cerebellar tPA levels exert a common pathway of Purkinje cell damage. Therapeutically lowering cerebellar tPA levels may represent a novel means of preserving Purkinje cell integrity and motor coordination across a wide range of neurodegenerative diseases. PMID:23939410

Cops, Elisa J; Sashindranath, Maithili; Daglas, Maria; Short, Kieran M; da Fonseca Pereira, Candida; Pang, Terence Y; Lijnen, Roger H; Smyth, Ian M; Hannan, Anthony J; Samson, Andre L; Medcalf, Robert L

2013-08-09

372

Tissue-Type Plasminogen Activator Regulates the Neuronal Uptake of Glucose in the Ischemic Brain  

PubMed Central

The ability to sense and adapt to hypoxic conditions plays a pivotal role in neuronal survival. Hypoxia induces the release of tissue-type plasminogen activator (tPA) from cerebral cortical neurons. We found that the release of neuronal tPA or treatment with recombinant tPA (rtPA) promotes cell survival in cerebral cortical neurons previously exposed to hypoxic conditions in vitro or experimental cerebral ischemia in vivo. Our studies using liquid chromatography and tandem mass spectrometry revealed that tPA activates the mammalian target of rapamycin (mTOR) pathway which adapts cellular processes to the availability of energy and metabolic resources. We found that mTOR activation leads to accumulation of the hypoxia-inducible factor-1? (HIF-1?) and induction and recruitment to the cell membrane of the HIF-1?-regulated neuronal transporter of glucose GLUT3. Accordingly, in vivo positron emission tomography studies with 18-fluorodeoxyglucose in mice overexpressing tPA in neurons show that neuronal tPA induces the uptake of glucose in the ischemic brain and that this effect is associated with decrease in the volume of the ischemic lesion and improved neurological outcome following the induction of ischemic stroke. Our data indicate that tPA activates a cell signaling pathway that allows neurons to sense and adapt to oxygen and glucose deprivation.

Wu, Fang; Wu, Jialing; Nicholson, Andrew D.; Echeverry, Ramiro; Haile, Woldeab B.; Catano, Marcela; An, Jie; Lee, Andrew K.; Duong, Duc; Dammer, Eric B.; Seyfried, Nicholas T.; Tong, Frank C.; Votaw, John R.; Medcalf, Robert; Yepes, Manuel

2012-01-01

373

Adipose tissue inflammation: Feeding the development of type 2 diabetes mellitus.  

PubMed

The global increase in obesity-induced type 2 diabetes (T2DM) represents a burden for healthcare systems worldwide. Of particular concern is the increased morbidity associated with T2DM, in particular cardiovascular disease (CVD), leading to premature death. Obesity initially leads to the development of insulin resistance in adipose and other tissues. Insulin resistance is initially compensated by increased insulin secretion but ultimately insufficient insulin is produced and this leads to the development of T2DM. Understanding the causal mechanisms underpinning the development of obesity-induced insulin resistance may be beneficial in improving quality of life and life expectancy, with the potential for a major global impact on healthcare systems. There is abundant evidence from animal, human studies and in vitro studies to support functional roles for a number of inflammatory factors in obesity-induced insulin resistance. In this review we provide an overview of the evidence supporting a fundamental role for the fluid phase (in particular the complement system) and the cellular components of the innate immune system in the pathogenesis of obesity-induced insulin resistance and ultimately development of T2DM. PMID:23816302

Richardson, Victoria R; Smith, Kerrie A; Carter, Angela M

2013-05-16

374

Early intracardiac thrombosis in preterm infants and thrombolysis with recombinant tissue type plasminogen activator  

PubMed Central

OBJECTIVES—To determine the incidence of catheter related thrombosis and to test the efficacy of recombinant tissue type plasminogen activator (rt-PA) in preterm infants.?STUDY DESIGN—From January 1995 to December 1998, echocardiography was performed in the first few days of life in 76 very low birthweight (? 1500 g) infants out of a total of 147 having an umbilical catheter placed. When intracardiac thrombosis was diagnosed, rt-PA infusion was performed.?RESULTS—Four infants (5%) developed an intracardiac thrombosis during the first few days of life. In three of them, rt-PA at a dose of 0.4-0.5 mg/kg in a 20-30 minute bolus led to dissolution of the clot. One patient received a three hour infusion after the bolus, at a dose of 0.1 mg/kg/h, with resolution of the thrombus. No systemic effects were observed after rt-PA infusion.?CONCLUSIONS—Early thrombosis may occur as a complication of umbilical catheterisation in preterm infants; early echocardiographic detection of this disorder allows complete, safe, and rapid lysis with rt-PA.??

Ferrari, F; Vagnarelli, F; Gargano, G; Roversi, M; Biagioni, O; Ranzi, A; Cavazzuti, G

2001-01-01

375

Tissue type plasminogen activator antigen and activity in sickle cell disease.  

PubMed Central

To investigate the hypothesis that diminished endothelial fibrinolysis is present in sickle cell (SS) disease plasma, tissue type plasminogen activator (t-PA) antigen titres were measured before and after a standard stimulus of endothelial t-PA release (venous occlusion of the arm), and plasma t-PA activities after venous occlusion in 33 subjects with SS disease and in 32 healthy subjects. Mean plasma t-PA antigen titres before and after venous occlusion, and mean plasma t-PA activities after venous occlusion did not differ significantly between SS patients and normal subjects. No significant differences in mean t-PA antigen and activity were observed between samples taken from inpatients being treated for acute pain crisis (18 subjects, 30 samples) and samples taken from subjects in the steady state (23 subjects, 26 samples). No consistent differences were seen between painful crisis and steady state samples in eight SS patients studied while in crisis and in the steady state. No correlation was observed between any fibrinolytic variable in SS patients and the overall severity of microvascular occlusive disease as measured by a standard scoring system. It is concluded that the capacity of endothelium to synthesise and release t-PA is not impaired in SS disease, and that excessive inhibition of released t-PA, leading to reduced t-PA activity in plasma is also not a feature of SS disease, either in the steady state or during painful crisis.

Francis, R B

1988-01-01

376

Autonomous functions of structural domains on human tissue-type plasminogen activator.  

PubMed Central

Transfected mouse Ltk- cells were employed for transient expression of recombinant human tissue-type plasminogen activator (t-PA; EC 3.4.21.31) or of recombinant-t-PA deletion proteins, encoded by SV40-pBR322-derived t-PA cDNA plasmids. The t-PA cDNA deletion mutants have two features in common, i.e., cDNA programming the signal peptide and the coding region for the light chain. Consequently, recombinant t-PA mutant proteins are efficiently secreted and display plasminogen activator activity. The gene encoding the amino-terminal heavy chain [an array of structural domains homologous to other plasma proteins (finger, epidermal growth factor, and kringle domains)] was mutated using restriction endonucleases to delete one or more structural domains. The stimulatory effect of fibrinogen fragments on the plasminogen activator activity of t-PA was demonstrated to be mediated by the kringle K2 domain and to a lesser extent by the finger/epidermal growth factor region but not by the kringle K1 domain. These data correlate well with the fibrin-binding properties of the recombinant t-PA deletion proteins, indicating that the stimulation of the activity by fibrinogen fragments is based on aligning the substrate plasminogen and t-PA on the fibrin matrix. Our results support the evolutionary concept of exon shuffling, arranging structural domains that constitute autonomous functions of the protein. Images

van Zonneveld, A J; Veerman, H; Pannekoek, H

1986-01-01

377

A novel function of tissue-type transglutaminase: protein disulphide isomerase.  

PubMed Central

We have found that tissue-type transglutaminase (tTG), also called TGc, TGase2 and Galpha(h), has the activity of protein disulphide isomerase (PDI). We have shown that tTG converts completely reduced/denatured inactive RNase A molecule to the native active enzyme. The PDI activity of tTG was strongly inhibited by bacitracin, which is a frequently used inhibitor of conventional PDI activity. It was substantially inhibited by the simultaneous presence of other potential substrate proteins such as completely reduced BSA, but not by native BSA. This activity was especially high in the presence of GSSG, but not GSH. The addition of GSH to the reaction mixture in the presence of GSSG at a fixed concentration up to at least 200-fold excess did not very substantially inhibit the PDI activity. It is possible that tTG can exert PDI activity in a fairly reducing environment like cytosol, where most of tTG is found. It is quite obvious from the following observations that PDI activity of tTG is catalysed by a domain different from that used for the transglutaminase reaction. Although the alkylation of Cys residues in tTG completely abolished the transglutaminase activity, as was expected, it did not affect the PDI activity at all. This PDI activity did not require the presence of Ca(2+). It was not inhibited by nucleotides including GTP at all, unlike the other activity of tTG.

Hasegawa, Go; Suwa, Motoi; Ichikawa, Yasuo; Ohtsuka, Tetsuro; Kumagai, Satoru; Kikuchi, Masashi; Sato, Yoshitaka; Saito, Yuji

2003-01-01

378

Cell type-associated differences in migration, survival, and immunogenicity following grafting in CNS tissue.  

PubMed

Cell transplantation has been suggested to display several neuroprotective and/or neuroregenerative effects in animal models of central nervous system (CNS) trauma. However, while most studies report on clinical observations, currently little is known regarding the actual fate of the cell populations grafted and whether or how the brain's innate immune system, mainly directed by activated microglia and astrocytes, interacts with autologous cellular implants. In this study, we grafted well-characterized neural stem cell, mouse embryonic fibroblast, dendritic cell, bone marrow mononuclear cell, and splenocyte populations, all isolated or cultured from C57BL/6-eGFP transgenic mice, below the capsula externa (CE) of healthy C57BL/6 mice and below the inflamed/demyelinated CE of cuprizone-treated C57BL/6 mice. Two weeks postgrafting, an extensive quantitative multicolor histological analysis was performed in order (i) to quantify cell graft localization, migration, survival, and toxicity and (ii) to characterize endogenous CNS immune responses against the different cell grafts. Obtained results indicate dependence on the cell type grafted: (i) a different degree of cell graft migration, survival, and toxicity and (ii) a different organization of the endogenous immune response. Based on these observations, we warrant that further research should be undertaken to understand-and eventually control-cell graft-induced tissue damage and activation of the brain's innate immune system. The latter will be inevitable before cell grafting in the CNS can be performed safely and successfully in clinical settings. PMID:22472278

Praet, Jelle; Reekmans, Kristien; Lin, Dan; De Vocht, Nathalie; Bergwerf, Irene; Tambuyzer, Bart; Daans, Jasmijn; Hens, Niel; Goossens, Herman; Pauwels, Patrick; Berneman, Zwi; Van der Linden, Annemie; Ponsaerts, Peter

2012-04-02

379

Effect of modulated ultrasound parameters on ultrasound-induced thrombolysis  

NASA Astrophysics Data System (ADS)

The potential of ultrasound to enhance enzyme-mediated thrombolysis by application of constant operating parameters (COP) has been widely demonstrated. In this study, the effect of ultrasound with modulated operating parameters (MOP) on enzyme-mediated thrombolysis was investigated. The MOP protocol was applied to an in vitro model of thrombolysis. The results were compared to a COP with the equivalent soft tissue thermal index (TIS) over the duration of ultrasound exposure of 30 min (p < 0.14). To explore potential differences in the mechanism responsible for ultrasound-induced thrombolysis, a perfusion model was used to measure changes in average fibrin pore size of clot before, after and during exposure to MOP and COP protocols and cavitational activity was monitored in real time for both protocols using a passive cavitation detection system. The relative lysis enhancement by each COP and MOP protocol compared to alteplase alone yielded values of 33.69 ± 12.09% and 63.89 ± 15.02% in a thrombolysis model, respectively (p < 0.007). Both COP and MOP protocols caused an equivalent significant increase in average clot pore size of 2.09 × 10-2 ± 0.01 µm and 1.99 × 10-2 ± 0.004 µm, respectively (p < 0.74). No signatures of inertial or stable cavitation were observed for either acoustic protocol. In conclusion, due to mechanisms other than cavitation, application of ultrasound with modulated operating parameters has the potential to significantly enhance the relative lysis enhancement compared to application of ultrasound with constant operating parameters.

Soltani, Azita; Volz, Kim R.; Hansmann, Doulas R.

2008-12-01

380

An inhibition ELISA for the quantification of collagens type I and type II in cyanogen bromide-digested tissues using fragment-directed antibodies.  

PubMed

The quantification of connective tissue components in small tissue samples is of great importance for the examination of drug-induced changes in the development of the mammalian embryo. An inhibition-ELISA for the quantification of collagens type I and type II in CNBr-digested tissue samples was developed. Fragments of type I collagen were produced by CNBr-cleavage of the pure collagen and partially purified by gel filtration chromatography. A mixture of fragments was used to immunize rabbits. Antisera with highest titres were absorbed with immobilized fibronectin and collagens type II, III, V and I. The eluted antibodies exhibited specificity for alpha 2(I)-CB4, exclusively. These antibodies, as well as the previously described antibodies with specificity for alpha 1(II)-CB8, were used for the development of an inhibition-ELISA. The sensitivity of the assay is 0.3 micrograms/ml for collagen I and 3 micrograms/ml for collagen II. To evaluate the value and practicability of the ELISA we have estimated the amounts of both collagens in biochemically well characterized tissues (skin, aorta, chondrosarcoma) and have performed an initial determination in mouse embryos. PMID:2074114

Schröter-Kermani, C; Ochsner-Welpelo, I; Kittelberger, R

381

The expression of a nitric oxide derivative, tissue inhibitors of metalloproteinase-3, and tissue inhibitors of metalloproteinase-4 in chronic periodontitis with type 2 diabetes mellitus  

PubMed Central

Purpose The purpose of this study was to analyze the expression of inducible nitric oxide synthases (iNOS), tissue inhibitors of metalloproteinase (TIMP)-3, and TIMP-4 in the gingival tissues of periodontal patients with or without type 2 diabetes mellitus (DM). Methods Depending on the patient's systemic condition and clinical criteria of the gingiva, each gingival sample was classified into one of three groups. Sixteen clinically, systemically healthy patients (group 1), 16 periodontal patients (group 2), and 16 periodontal patients with DM (group 3) were included. Tissue samples in each group were collected, prepared, and analyzed by western blotting. Quantification of the relative amount of TIMP-3, TIMP-4, and iNOS was performed. Results The expression levels of iNOS and TIMP-3 both increased in group 1, group 2, and group 3 in increasing order, and were significantly higher in both group 2 and group 3 as compared to group 1 (P<0.05). The expression levels of TIMP-4 increased in the same order, but significantly increased in group 2 as compared to group 1, in group 3 as compared to group 1, and group 3 as compared to group 2 (P<0.05). Conclusions This study demonstrated that iNOS, TIMP-3, and TIMP-4 might be involved in the progression of periodontal inflammation associated with type 2 DM. It is thought that further study of these factors can be applied practically for the diagnosis and control of periodontitis in diabetics.

Jung, Hyun-Yub; Kim, Yong-Gun; Park, Jin-Woo; Suh, Jo-Young

2013-01-01

382

Current Threshold for Nerve Stimulation Depends on Electrical Impedance of the Tissue: A Study of Ultrasound-Guided Electrical Nerve Stimulation of the Median Nerve  

Microsoft Academic Search

BACKGROUND: Understanding the mechanisms causing variation in current thresh- olds for electrical nerve stimulation may improve the safety and success rate of peripheral nerve blocks. Electrical impedance of the tissue surrounding a nerve may affect the response to nerve stimulation. In this volunteer study, we investi- gated the relationship between impedance and current threshold needed to obtain a neuromuscular response.

Axel R. Sauter; Michael S. Dodgson; Håvard Kalvøy; Sverre Grimnes; Audun Stubhaug; Øivind Klaastad

2009-01-01

383

Update on ultrasound elastography: Miscellanea. Prostate, testicle, musculo-skeletal.  

PubMed

Nowadays ultrasound elastosonography is an established technique, although with limited clinical application, used to assess tissue stiffness, which is a parameter that in most cases is associated with malignancy. However, although a consistent number of articles have been published about several applications of elastosonography, its use in certain human body districts is still not well defined. In this paper we write on the use of elastosonography in prostate, testicle and musculo-skeletal apparatus. We report and compare the work of several authors, different type of elastosonography (shear wave, strain elastography, etc.) and instrumental data obtained in the study of both benign and malignant lesions. PMID:23816164

Correas, J M; Drakonakis, E; Isidori, A M; Hélénon, O; Pozza, C; Cantisani, V; Di Leo, N; Maghella, F; Rubini, A; Drudi, F M; D'ambrosio, F

2013-06-28

384

Successful Treatment of Renovascular Hypertension due to Fibromuscular Dysplasia by Intravascular Ultrasound-Guided Atherectomy  

Microsoft Academic Search

A 22-year-old man presented with renovascular hypertension, based on a stenosis of the distal portion of the right renal artery with a ‘string of beads’-like appearance. An intravascular ultrasound image at the renal artery lesion revealed irregularity of the vascular wall. Directional atherectomy was performed and histopathology of atherectomised tissues showed medial fibroplasia, a common type of fibromuscular dysplasia. After

Yoichi Hoshino; Tetsuya Nakamura; Akihiko Nakano; Zen Isobe; Masahiko Suguta; Tomoyuki Tomita; Tomoyuki Yokoyama; Akira Hasegawa; Masahiko Kurabayashi

2002-01-01

385

Imaging Ultrasound Guidance and on-line Estimation of Thermal Behavior in HIFU Exposed Targets  

Microsoft Academic Search

Elevated temperatures have been used for many years to combat several diseases including treatment of certain types of cancers\\/tumors. High Intensity Focused Ultrasound (HIFU) has emerged as a potential non-invasive modality for trackless targeting of deep-seated cancers of human body. For the procedures which require thermal elevation such as hyperthermia and tissue ablation, temperature becomes a parameter of vital importance

Sunita Chauhan; Amir Haryanto

2006-01-01

386

Involvement of cavitation in the appearance of hyperechoic regions in ultrasound image visualization of high intensity focused ultrasound therapy: in-vivo results  

Microsoft Academic Search

High intensity focused ultrasound (HIFU) treatment of soft tissues has been shown to result in a hyperechoic region in B-mode ultrasound (US) images. This is believed to result from bubble activity at the HIFU focus. Here, we report our in vivo results of detecting inertial and stable cavitation in correlation with the appearance of a hyperechoic region. The ultrasound system

M. A. Rabkin; Vesna Zderic; Shahram Vaezy

2004-01-01

387

Endogenous tissue-type plasminogen activator is protective during Escherichia coli-induced abdominal sepsis in mice  

Microsoft Academic Search

Sepsis is associated with enhanced production of tissue-type plasminogen activator (tPA). We investigated the function of endogenous tPA in the immune responses to Escherichia coli-induced abdominal sepsis using tPA gene-deficient (tPA(-\\/-)) and normal wild-type (WT) mice. tPA(-\\/-) mice demonstrated an impaired defense against E. coli peritonitis as indicated by higher bacterial loads at the primary site of the infection, enhanced

R. Renckens; J. J. T. H. Roelofs; S. Florquin; Vos de A. F; Pater de J. M; H. R. Lijnen; P. Carmeliet; Veer van't C; Poll van der T

2006-01-01

388

Accelerated Focused Ultrasound Imaging  

PubMed Central

One of the most, basic trade-offs in ultrasound imaging involves frame rate, depth, and number of lines. Achieving good spatial resolution and coverage requires a large number of lines, leading to decreases in frame rate. An even more serious imaging challenge occurs with imaging modes involving spatial compounding and 3-D/4-D imaging, which are severely limited by the slow speed of sound in tissue. The present work can overcome these traditional limitations, making ultrasound imaging many-fold faster. By emitting several beams at once, and by separating the resulting overlapped signals through spatial and temporal processing, spatial resolution and/or coverage can be increased by many-fold while leaving frame rates unaffected. The proposed approach can also be extended to imaging strategies that do not involve transmit beamforming, such as synthetic aperture imaging. Simulated and experimental results are presented where imaging speed is improved by up to 32-fold, with little impact on image quality. Object complexity has little impact on the method’s performance, and data from biological systems can readily be handled. The present work may open the door to novel multiplexed and/or multidimensional protocols considered impractical today.

White, P. Jason; Thomenius, Kai; Clement, Gregory T.

2010-01-01

389

Intracardiac thrombus formation with rapidly progressive heart failure in the neonate: treatment with tissue type plasminogen activator  

Microsoft Academic Search

A newborn is described in whom the use of a central venous line was complicated by septicaemia and by intracardiac thrombus formation with tricuspid valve insufficiency and heart failure. Besides antibiotics, treatment consisted of tissue type plasminogen activator (tPA) for three days. This treatment resulted in the disappearance of the thrombus and the tricuspid insufficiency. No adverse effects were noted.

B Van Overmeire; P J Van Reempts; K J Van Acker

1992-01-01

390

Analgesic effects induced by TENS and electroacupuncture with different types of stimulating electrodes on deep tissues in human subjects  

Microsoft Academic Search

Effects of conditioning peripheral nerve stimulation with different types of stimulating electrodes on pain thresholds in various deep tissues were measured in human subjects. Cone-shaped metal (? 13 mm), rubber (? 13 mm), and large soft surface electrodes (50 × 150 mm) were used for transcutaneous electrical nerve stimulation (TENS), and insulated and non-insulated acupuncture needles (diameter: 240 ?m) were

Keisou Ishimaru; Kenji Kawakita; Masakazu Sakita

1995-01-01

391

Human tissue-type plasminogen activator releases fibrinopeptides A and B from fibrinogen.  

PubMed Central

In five patients with venous thromboembolic disease treated with recombinant tissue-type plasminogen activator (rt-PA), there was a marked increase in the mean concentrations of fibrinopeptide A (from 0.6 to 5.9 nM; P less than 0.0001) and desarginine fibrinopeptide B (from 5.6 nM to 24.1 nM; P less than 0.01) 30 min after a bolus of rt-PA (0.6 mg/kg). Thrombin was unlikely to be responsible because the levels of desarginine fibrinopeptide B exceeded those of fibrinopeptide A and the changes occurred despite concomitant heparin therapy. The purpose of this study therefore, was to determine whether rt-PA directly releases the fibrinopeptides from fibrinogen. Incubation of rt-PA with heparinized plasma or purified fibrinogen resulted in time and dose-dependent release of both fibrinopeptide A and B. Contaminating thrombin was not responsible for this activity by the following criteria: the rate of rt-PA mediated fibrinopeptide B release was considerably faster than that of fibrinopeptide A, and fibrinopeptide release was unaffected by heparin, hirudin, or a monospecific antithrombin IgG. Aprotinin also had no effect on fibrinopeptide release, indicating that this activity was not plasmin mediated. Fibrinopeptide release was shown to be due to rt-PA because this activity was completely blocked by a monoclonal antibody against the enzyme. Further, the specificity of rt-PA for the thrombin cleavage sites on fibrinogen was confirmed by the demonstration that rt-PA released fibrinopeptide A or fibrinopeptide B from fibrinopeptide A or B-containing substrates, respectively. These studies thus demonstrate that (a) rt-PA releases fibrinopeptides A and B from fibrinogen thereby indicating that this enzyme is not specific for plasminogen, and (b) plasma fibrinopeptide A and desarginine fibrinopeptide B levels are not specific markers of thrombin action on fibrinogen in patients receiving rt-PA.

Weitz, J I; Cruickshank, M K; Thong, B; Leslie, B; Levine, M N; Ginsberg, J; Eckhardt, T

1988-01-01

392

Analysis of Artificial Radiocarbon in Different Skeletal and Dental Tissue Types to Evaluate Date of Death  

SciTech Connect

Radiocarbon dating, with special reference to the modern bomb-curve, can provide useful information to elucidate the date of death of skeletonized human remains. Interpretation can be enhanced with analysis of different types of tissues within a single skeleton because of the known variability of formation times and remodeling rates. Analysis of radiocarbon content of teeth, especially the enamel in tooth crowns provides information about the date of formation in the childhood years and in consideration of the known timing of tooth formation can be used to estimate the birth date after 1950 A.D. Radiocarbon analysis of modern cortical and trabecular bone samples from the same skeleton may allow proper placement on the pre-1963 or post-1963 sides of the bomb-curve since most trabecular bone generally undergoes more rapid remodeling than does most cortical bone. Pre-1963 bone formation would produce higher radiocarbon values for most trabecular bone than for most cortical bone. This relationship is reversed for formation after 1963. Radiocarbon analysis was conducted in this study on dental, cortical and trabecular bone samples from two adult individuals of known birth (1925 and 1926) and death dates (1995 and 1959). As expected, the dental results correspond to pre-bomb bomb-curve values reflecting conditions during the childhoods of the individuals. The curve radiocarbon content of most bone samples reflected the higher modern bomb-curve values. Within the bone sample analyses, the values of the trabecular bone were higher than those of cortical bone and supported the known placement on the pre-1963 side of the bomb-curve.

Ubelaker, D H; Buchholz, B A; Stewart, J

2005-07-19

393

Novel actions of tissue-type plasminogen activator in chronic kidney disease: a paradigm shift  

PubMed Central

Tissue-type plasminogen activator (tPA) is traditionally viewed as a simple serine protease whose main function is to convert plasminogen into biologically active plasmin. As a protease, tPA plays a crucial role in regulating blood fibrinolysis, in maintaining the homeostasis of extracellular matrix (ECM) and in modulating the post-translational activation of growth factors. However, emerging evidence indicates that tPA may also function as a cytokine that transmits its signal across the cell membrane, initiates a diverse array of intracellular signaling, and dictates gene expression in the nuclei. Structurally, tPA is a kringle-containing protein that shares significant similarity to other classic cytokines such as hepatocyte growth factor (HGF) and macrophage-stimulating protein (MSP). Although there is no dedicated receptor, tPA binds to the cell membrane low density lipoprotein (LDL) receptor-related protein-1 (LRP-1), triggers LRP-1 tyrosine phosphorylation, and activates various intracellular signaling. As a cytokine, tPA plays a pivotal role in the pathogenesis of renal interstitial fibrosis through diverse mechanisms. It induces matrix matelloproteinase-9 (MMP-9) gene expression in renal interstitial fibroblasts, which causes the destruction of the tubular basement membrane (TBM), thereby facilitating tubular epithelial to mesenchymal transition (EMT). tPA also potentiates myofibroblast activation from quiescent interstitial fibroblasts through LRP-1-mediated recruitment of ?1 integrin signaling. Furthermore, tPA acts as a survival factor that protects renal interstitial fibroblasts/myofibroblasts from apoptosis, thereby resulting in an expansion of myofibroblast populations in diseased kidney. Together, a growing body of evidence has implicated tPA as a fibrogenic cytokine that promotes the progression of kidney diseases. These new findings have radically changed our conception of tPA in renal fibrogenesis and represent a paradigm shift towards uncovering its cytokine function. A better understanding of renal tPA biology will ultimately translate into more rational therapeutic remedies for patients with chronic kidney fibrosis.

Hu, Kebin; Mars, Wendy M.; Liu, Youhua

2009-01-01

394

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

SciTech Connect

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

Wood, Bradford J.; Frenkel, V.; Viswanathan, A.; Dromi, S.; Oh, K.; Kam, A.; Li, K. C. P. [National Institutes of Health, Dept. Diagnostic Radiology, Clinical Center, Bethesda, MD (United States); Yanof, J.; Bauer, C. [Philips Medical Systems, Computed Tomography Clinical Science Dept., Cleveland, OH (United States); Kruecker, J. [Philips Research, Clinical Research Program, Briarcliff Manor, NY (United States); Seip, R. [Focus Surgery, Indianapolis, IN (United States)

2006-05-08

395

Liver fat content is linked to inflammatory changes in subcutaneous adipose tissue in type 2 diabetes patients.  

PubMed

BACKGROUND: Patients with type 2 diabetes mellitus (T2DM) are typically overweight and have an increased liver fat content (LFAT). High LFAT may be explained by an increased efflux of free fatty acids from the adipose tissue, which is partly instigated by inflammatory changes. This would imply an association between inflammatory features of the adipose tissue and liver fat content. OBJECTIVE: To analyse associations between inflammatory features of the adipose tissue and liver fat content. DESIGN: A cross-sectional study. PATIENTS: Twenty-seven obese patients with insulin-treated T2DM were studied. MEASUREMENTS: LFAT content was measured by proton magnetic resonance spectroscopy. A subcutaneous (sc) fat biopsy was obtained to determine morphology and protein levels within adipose tissue. In addition to fat cell size, the percentage of macrophages and the presence of crown-like structures (CLSs) within sc fat were assessed by CD68-immunohistochemical staining. RESULTS: Mean LFAT percentage was 11·1 ± 1·7% (range: 0·75-32·9%); 63% of the patients were diagnosed with an elevated LFAT (upper range of normal ?5·5%). Whereas adipocyte size did not correlate with LFAT, 3 of 4 subjects with CLSs in sc fat had elevated LFAT and the percentage of macrophages present in sc adipose tissue was positively associated with LFAT. Protein concentrations of adiponectin within adipose tissue negatively correlated with LFAT. Adipose tissue protein levels of the key inflammatory adipokine plasminogen activator inhibitor-1 (PAI-1) were positively associated with LFAT. CONCLUSIONS: Several pro-inflammatory changes in sc adipose tissue associate with increased LFAT content in obese insulin-treated patients with T2DM. These findings suggest that inflammatory changes at the level of the adipose tissue may drive liver fat accumulation. PMID:23167778

Jansen, Henry J; Vervoort, Gerald M; van der Graaf, Marinette; Stienstra, Rinke; Tack, Cees J

2012-11-20

396

Physical mechanisms of the therapeutic effect of ultrasound (a review)  

Microsoft Academic Search

Therapeutic ultrasound is an emerging field with many medical applications. High intensity focused ultrasound (HIFU) provides\\u000a the ability to localize the deposition of acoustic energy within the body, which can cause tissue necrosis and hemostasis.\\u000a Similarly, shock waves from a lithotripter penetrate the body to comminute kidney stones, and transcutaneous ultrasound enhances\\u000a the transport of chemotherapy agents. New medical applications

M. R. Bailey; V. A. Khokhlova; O. A. Sapozhnikov; S. G. Kargl; L. A. Crum

2003-01-01

397

Two-stage multishape segmentation of brain structures using image intensity, tissue type, and location information1  

PubMed Central

Purpose: The authors propose a fast, robust, nonparametric, entropy-based, coupled, multishape approach to segment subcortical brain structures from magnetic resonance images (MRIs). Methods: The proposed method uses three types of information: Image intensity, tissue types, and locations of structures. The image intensity information is captured by estimating the probability density function (pdf) of the image intensities in each structure. The tissue type information is captured by applying an unsupervised tissue segmentation method to the image and estimating a probability mass function (pmf) for the tissue type of each structure. The location information is captured by estimating pdf of the location of each structure from the training datasets. The resulting pmf’s and pdf’s are used to define an entropy function whose minimum corresponds to a desirable segmentation of the structures. The authors propose a three-step optimization strategy for the segmentation method. In the first step, a powerful automatic initialization method is developed based on tissue type and location information of the structures. In the second step, a quasi-Newton method is used to optimize the parameters of the energy function. To speed up the iterations, derivatives of the energy function with respect to its parameters are analytically derived and used in the optimization process. In the last step, the limitations related to the prior shape model are removed and a level-set method is applied for the fine tuning of the segmentation results. Results: The proposed method is applied to two different datasets and the results are compared to those of previous methods in literature. Experimental results are presented for lateral ventricles, caudate, thalamus, putamen, pallidum, hippocampus, and amygdala. Conclusions: The results illustrate superior performance of the proposed segmentation method compared to other methods in literature. The execution time of the algorithm is a few minutes, suitable for a variety of applications.

Akhondi-Asl, Alireza; Soltanian-Zadeh, Hamid

2010-01-01

398

A DERATING METHOD FOR THERAPEUTIC APPLICATIONS OF HIGH INTENSITY FOCUSED ULTRASOUND  

PubMed Central

Current methods of determining high intensity focused ultrasound (HIFU) fields in tissue rely on extrapolation of measurements in water assuming linear wave propagation both in water and in tissue. Neglecting nonlinear propagation effects in the derating process can result in significant errors. In this work, a new method based on scaling the source amplitude is introduced to estimate focal parameters of nonlinear HIFU fields in tissue. Focal values of acoustic field parameters in absorptive tissue are obtained from a numerical solution to a KZK-type equation and are compared to those simulated for propagation in water. Focal waveforms, peak pressures, and intensities are calculated over a wide range of source outputs and linear focusing gains. Our modeling indicates, that for the high gain sources which are typically used in therapeutic medical applications, the focal field parameters derated with our method agree well with numerical simulation in tissue. The feasibility of the derating method is demonstrated experimentally in excised bovine liver tissue.

Bessonova, O.V.; Khokhlova, V.A.; Canney, M.S.; Bailey, M.R.; Crum, L.A.

2010-01-01

399

CT Imaging of facial trauma. The role of different types of reconstruction. Part II - soft tissues  

PubMed Central

Summary Background: Injury to facial soft tissues as a complication of skeleton fractures is an important problem among patients with facial trauma. The aim of this work was to assess the value of multiplanar and three-dimensional (3D) reconstruction computed tomography (CT) images obtained by using multi-detector row technology in spiral data acquisition in patients with facial injuries of soft tissue. Material/Methods: Sixty-seven patients diagnosed with injury to the facial skeleton underwent a CT scan with the use of GE Hispeed Qx/i scanner. For each patient: a two-dimensional (2D) multiplanar reconstruction (MPR), maximum intensity projection (MIP), and 3D volume rendering (VR) were conducted. Post-injury lesions of soft tissues were assessed. During the assessment of the post-injury lesions of soft tissues, the following features were evaluated: Extraocular muscle and fat tissue herniation through fractures in the medial and inferior orbital walls. Fluid in the sinuses and in the nasal cavity. Subcutaneous tissue emphysema. Results: For subcutaneous emphysema and sinus fluid imaging, both the axial and the 2D image reconstruction proved comparably effective. However, 2D reconstructions were superior to transverse plane images with regard to herniations into fractures of the inferior orbital wall. 3D reconstruction has no importance in diagnosing soft tissue injuries. Conclusions: Multiplanar CT reconstructions increase the effectiveness of imaging of orbital tissue herniations, especially in case of fractures in the inferior orbital wall. In suspected soft tissue herniations, as well as prior to surgical treatment, spiral CT with 2D multiplanar reconstructions should be the method of choice.

Myga-Porosilo, Jolanta; Skrzelewski, Stanislaw; Sraga, Wojciech; Borowiak, Hanna; Jackowska, Zuzanna; Kluczewska, Ewa

2011-01-01

400

Monoclonal antibody to intermediate filaments of cytokeratin type. I. Drug studies and reactivity with cultured cells and tissue sections.  

PubMed

Establishment of a mouse-mouse hybridoma and partial characterization of IgM monoclonal antibody (M-04) identifying cytoplasmic filamentous structures is described. Immunofluorescence performed on a panel of various cultured human cell types as well as on frozen sections of normal and tumour tissues revealed specificity of M-04 antibody for cells of epithelial origin. Using MCF-7 cell line as a model, staining patterns of microtubules, microfilaments and M-04-target filaments in untreated cells were compared with those pretreated with Colcemid and Cytochalasin B. From both differential staining of various cell types and the results of drug studies it is concluded that monoclonal antibody M-04 binds to intermediate filaments of cytokeratin type. Furthermore, restricted expression of M-04 target determinant among epithelial tissues is suggested from the lack of reaction in stratified skin epithelium. PMID:2578996

Bártek, J; Kovarík, J; Lauerová, L; Munzarová, M

1985-01-01