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1

Ultrasound-responsive thrombus treatment with zinc-stabilized gelatin nano-complexes of tissue-type plasminogen activator  

E-print Network

#12;Ultrasound-responsive thrombus treatment with zinc-stabilized gelatin nano-complexes of tissue complexes Key words: t-PA, thrombolytic therapy, gelatin, metal ions, ultrasound #12;1 ABSTRACT This study is undertaken to design zinc-stabilized gelatin nano-complexes of tissue-type plasminogen activator (t

Takada, Shoji

2

Tissue identification by ultrasound  

NASA Technical Reports Server (NTRS)

The ultrasonic properties of animal and human soft tissue were measured over the frequency range of 1.5 to 10.0 MHz. The method employed a swept-frequency, coherent technique known as time delay spectrometry. Measurements of attenuation versus frequency on liver, backfat, kidney, pancreas, spleen, breast, and other tissue were made. Considerable attention was paid to tissue handling and in determining the effects of fixing on the attenuation of ultrasound in the tissue.

Lecroissette, D. H.; Heyser, R. C.; Gammell, P. M.; Wilson, R. L.

1978-01-01

3

Tissue types (image)  

MedlinePLUS

There are 4 basic types of tissue: connective tissue, epithelial tissue, muscle tissue, and nervous tissue. Connective tissue supports other tissues and binds them together (bone, blood, and lymph tissues). Epithelial tissue ...

4

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. PMID:22787391

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

2012-01-01

5

Effects of ultrasound and ultrasound contrast agent on vascular tissue  

PubMed Central

Background Ultrasound (US) imaging can be enhanced using gas-filled microbubble contrast agents. Strong echo signals are induced at the tissue-gas interface following microbubble collapse. Applications include assessment of ventricular function and virtual histology. Aim While ultrasound and US contrast agents are widely used, their impact on the physiological response of vascular tissue to vasoactive agents has not been investigated in detail. Methods and results In the present study, rat dorsal aortas were treated with US via a clinical imaging transducer in the presence or absence of the US contrast agent, Optison. Aortas treated with both US and Optison were unable to contract in response to phenylephrine or to relax in the presence of acetylcholine. Histology of the arteries was unremarkable. When the treated aortas were stained for endothelial markers, a distinct loss of endothelium was observed. Importantly, terminal deoxynucleotidyl transferase mediated dUTP nick-end-labeling (TUNEL) staining of treated aortas demonstrated incipient apoptosis in the endothelium. Conclusions Taken together, these ex vivo results suggest that the combination of US and Optison may alter arterial integrity and promote vascular injury; however, the in vivo interaction of Optison and ultrasound remains an open question. PMID:22805356

2012-01-01

6

On ultrasound image reconstruction by tissue density estimation  

Microsoft Academic Search

An inherent property of medical ultrasound imaging is the speckle noise that generally obscures the image and reduces the diagnostic image resolution and contrast. Consequently, substantial improvement of ultrasound images is an important prerequisite for ultrasound imaging. Some recent research has suggested that the spatial distribution of tissue densities may be used in ultrasound imaging to reconstruct images with fewer

Zheng Huang; Jingxin Zhang; Cishen Zhang

2010-01-01

7

Ovarian Tissue Characterization in Ultrasound: A Review.  

PubMed

Ovarian cancer is the most common cause of death among gynecological malignancies. We discuss different types of clinical and nonclinical features that are used to study and analyze the differences between benign and malignant ovarian tumors. Computer-aided diagnostic (CAD) systems of high accuracy are being developed as an initial test for ovarian tumor classification instead of biopsy, which is the current gold standard diagnostic test. We also discuss different aspects of developing a reliable CAD system for the automated classification of ovarian cancer into benign and malignant types. A brief description of the commonly used classifiers in ultrasound-based CAD systems is also given. PMID:25230716

Acharya, U Rajendra; Molinari, Filippo; Sree, S Vinitha; Swapna, G; Saba, Luca; Guerriero, Stefano; Suri, Jasjit S

2014-09-16

8

Tissue Bioeffects during Ultrasound-mediated Drug Delivery  

NASA Astrophysics Data System (ADS)

Ultrasound has been developed as both a valuable diagnostic tool and a potent promoter of beneficial tissue bioeffects for the treatment of cardiovascular disease. Vascular effects can be mediated by mechanical oscillations of circulating microbubbles, or ultrasound contrast agents, which may also encapsulate and shield a therapeutic agent in the bloodstream. Oscillating microbubbles can create stresses directly on nearby tissue or induce fluid effects that effect drug penetration into vascular tissue, lyse thrombi, or direct drugs to optimal locations for delivery. These investigations have spurred continued research into alternative therapeutic applications, such as bioactive gas delivery. This dissertation addresses a fundamental hypothesis in biomedical ultrasound: ultrasound-mediated drug delivery is capable of increasing the penetration of drugs across different physiologic barriers within the cardiovascular system, such as the vascular endothelium, blood clots, and smooth muscle cells.

Sutton, Jonathan

9

An incremental neural network for tissue segmentation in ultrasound images.  

PubMed

This paper presents an incremental neural network (INeN) for the segmentation of tissues in ultrasound images. The performances of the INeN and the Kohonen network are investigated for ultrasound image segmentation. The elements of the feature vectors are individually formed by using discrete Fourier transform (DFT) and discrete cosine transform (DCT). The training set formed from blocks of 4x4 pixels (regions of interest, ROIs) on five different tissues designated by an expert is used for the training of the Kohonen network. The training set of the INeN is formed from randomly selected ROIs of 4x4 pixels in the image. Performances of both 2D-DFT and 2D-DCT are comparatively examined for the segmentation of ultrasound images. PMID:17275135

Kurnaz, Mehmet Nadir; Dokur, Zümray; Olmez, Tamer

2007-03-01

10

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; Wang, Peng; Lewis, George; Olbricht, William

2009-04-01

11

Breast tissue composition and breast density measurements from ultrasound tomography  

NASA Astrophysics Data System (ADS)

It is known that breast cancer risk is greater in women with higher breast densities. Currently, breast density is measured using mammographic percent density, defined as the ratio of fibroglandular to total breast area on a two dimensional mammogram. Alternatively, systems that use ultrasound tomography (UST) create tomographic sound speed images of the patient's breast. These volumetric images can be useful as a diagnostic aid because it is also known that sound speed of tissue is proportional to the density of the tissue. The purpose of this work is to expand on the comparisons of the two imaging modalities by introducing new ultrasound tomography measurements that separate and quantify the fatty and dense tissue distributions within the breast. A total of 249 patients were imaged using both imaging modalities. By using k-means clustering, correlations beyond the volume averaged sound speed of the ultrasound images and the mammographic percent density were investigated. Both the ultrasound and mammographic images were separated into dense and fatty regions. Various associations between the global breast properties as well as separate tissue components were found.

Sak, Mark; Duric, Neb; Boyd, Norman; Littrup, Peter; West, Erik; Li, Cuiping

2012-03-01

12

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

13

Ultrasound heating in a tissue-bone phantom.  

PubMed

Temperature rise generated by focused ultrasound beams was tested on semipermanent tissue-bone phantoms. The phantoms were capped (sealed) plastic hollow cylindrical containers filled with tissue-mimicking material (TMM), in which were imbedded 25 microns diameter copper-constantan thermocouples (TC) and a piece of compact human or cow bone. The acoustic frequency specific attenuation coefficient of TMM was adjusted to be 0.3 dB cm-1 MHz-1 as specified by the FDA for a frequency range of 1-5 MHz. A high density 0.318 cm thick polyethylene sheet was chosen as the material to make caps of the phantoms. A formula developed to estimate the upper limit of temperature rises at tissue-bone interfaces generated by focused ultrasound has been proved to be appropriate experimentally using the semipermanent phantoms. PMID:7998378

O'Neill, T P; Winkler, A J; Wu, J

1994-01-01

14

Nakagami imaging for detecting thermal lesions induced by high-intensity focused ultrasound in tissue.  

PubMed

High-intensity focused ultrasound induces focalized tissue coagulation by increasing the tissue temperature in a tight focal region. Several methods have been proposed to monitor high-intensity focused ultrasound-induced thermal lesions. Currently, ultrasound imaging techniques that are clinically used for monitoring high-intensity focused ultrasound treatment are standard pulse-echo B-mode ultrasound imaging, ultrasound temperature estimation, and elastography-based methods. On the contrary, the efficacy of two-dimensional Nakagami parametric imaging based on the distribution of the ultrasound backscattered signals to quantify properties of soft tissue has recently been evaluated. In this study, ultrasound radio frequency echo signals from ex vivo tissue samples were acquired before and after high-intensity focused ultrasound exposures and then their Nakagami parameter and scaling parameter of Nakagami distribution were estimated. These parameters were used to detect high-intensity focused ultrasound-induced thermal lesions. Also, the effects of changing the acoustic power of the high-intensity focused ultrasound transducer on the Nakagami parameters were studied. The results obtained suggest that the Nakagami distribution's scaling and Nakagami parameters can effectively be used to detect high-intensity focused ultrasound-induced thermal lesions in tissue ex vivo. These parameters can also be used to understand the degree of change in tissue caused by high-intensity focused ultrasound exposures, which could be interpreted as a measure of degree of variability in scatterer concentration in various parts of the high-intensity focused ultrasound lesion. PMID:24264647

Rangraz, Parisa; Behnam, Hamid; Tavakkoli, Jahan

2014-01-01

15

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

16

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

PubMed Central

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 tissue into submicron-size fragments in a process termed boiling histotripsy, wherein the focused ultrasound wave superheats the tissue at the focus, producing a millimetre-size boiling or vapour bubble in several milliseconds. Yet the question of how this millimetre-size boiling bubble creates submicron-size tissue fragments remains. The hypothesis of this work is that tissue can behave as a liquid such that it forms a fountain and atomization 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/cm2) was aligned with an air-tissue interface meant to simulate the boiling bubble. Atomization and fountain formation were 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.

2012-01-01

17

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

18

TissuesTissues TissuesTissues group of similar cell types thatgroup of similar cell types that  

E-print Network

has four basic types of tissue:tissue: EpithelialEpithelial ConnectiveConnective Muscle TissuesTissues­­ Connective TissueConnective Tissue Loosely organized and composed ofLoosely organizedUsually binds organs or tissues to one anotherone another #12;3 TissuesTissues ­­ Connective TissueConnective

Cochran-Stafira, D. Liane

19

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

20

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

21

Three-dimensional ultrasound does not improve diagnosis of retained placental tissue compared to two-dimensional ultrasound.  

PubMed

The study objective was to improve ultrasonic diagnosis of retained placental tissue by measuring the volume of the uterine body and cavity using three-dimensional (3D) ultrasound. Twenty-five women who were to undergo surgical curettage due to suspected retained placental tissue were included. The volume of the uterine body and cavity was measured using the VOCAL imaging program. Twenty-one women had retained placental tissue histologically verified. Three of these had uterine volumes exceeding the largest volume observed in the normal puerperium. Seventeen of the 21 women had a uterine cavity volume exceeding the largest volume observed in the normal puerperium. In all 14 cases examined 28 days or more after delivery the cavity volume exceeded the largest volume observed in the normal puerperium. A large cavity volume estimated with 3D ultrasound is indicative of retained placental tissue. However, 3D ultrasound adds little or no diagnostic power compared to 2D ultrasound. PMID:25303033

Belachew, Johanna; Axelsson, Ove; Eurenius, Karin; Mulic-Lutvica, Ajlana

2015-01-01

22

Ultrasound-guided tissue fractionation by high intensity focused ultrasound in an in vivo porcine liver model  

PubMed Central

The clinical use of high intensity focused ultrasound (HIFU) therapy for noninvasive tissue ablation has been recently gaining momentum. In HIFU, ultrasound energy from an extracorporeal source is focused within the body to ablate tissue at the focus while leaving the surrounding organs and tissues unaffected. Most HIFU therapies are designed to use heating effects resulting from the absorption of ultrasound by tissue to create a thermally coagulated treatment volume. Although this approach is often successful, it has its limitations, such as the heat sink effect caused by the presence of a large blood vessel near the treatment area or heating of the ribs in the transcostal applications. HIFU-induced bubbles provide an alternative means to destroy the target tissue by mechanical disruption or, at its extreme, local fractionation of tissue within the focal region. Here, we demonstrate the feasibility of a recently developed approach to HIFU-induced ultrasound-guided tissue fractionation in an in vivo pig model. In this approach, termed boiling histotripsy, a millimeter-sized boiling bubble is generated by ultrasound and further interacts with the ultrasound field to fractionate porcine liver tissue into subcellular debris without inducing further thermal effects. Tissue selectivity, demonstrated by boiling histotripsy, allows for the treatment of tissue immediately adjacent to major blood vessels and other connective tissue structures. Furthermore, boiling histotripsy would benefit the clinical applications, in which it is important to accelerate resorption or passage of the ablated tissue volume, diminish pressure on the surrounding organs that causes discomfort, or insert openings between tissues. PMID:24843132

Khokhlova, Tatiana D.; Wang, Yak-Nam; Simon, Julianna C.; Cunitz, Bryan W.; Starr, Frank; Paun, Marla; Crum, Lawrence A.; Bailey, Michael R.; Khokhlova, Vera A.

2014-01-01

23

Ultrasound-guided tissue fractionation by high intensity focused ultrasound in an in vivo porcine liver model.  

PubMed

The clinical use of high intensity focused ultrasound (HIFU) therapy for noninvasive tissue ablation has been recently gaining momentum. In HIFU, ultrasound energy from an extracorporeal source is focused within the body to ablate tissue at the focus while leaving the surrounding organs and tissues unaffected. Most HIFU therapies are designed to use heating effects resulting from the absorption of ultrasound by tissue to create a thermally coagulated treatment volume. Although this approach is often successful, it has its limitations, such as the heat sink effect caused by the presence of a large blood vessel near the treatment area or heating of the ribs in the transcostal applications. HIFU-induced bubbles provide an alternative means to destroy the target tissue by mechanical disruption or, at its extreme, local fractionation of tissue within the focal region. Here, we demonstrate the feasibility of a recently developed approach to HIFU-induced ultrasound-guided tissue fractionation in an in vivo pig model. In this approach, termed boiling histotripsy, a millimeter-sized boiling bubble is generated by ultrasound and further interacts with the ultrasound field to fractionate porcine liver tissue into subcellular debris without inducing further thermal effects. Tissue selectivity, demonstrated by boiling histotripsy, allows for the treatment of tissue immediately adjacent to major blood vessels and other connective tissue structures. Furthermore, boiling histotripsy would benefit the clinical applications, in which it is important to accelerate resorption or passage of the ablated tissue volume, diminish pressure on the surrounding organs that causes discomfort, or insert openings between tissues. PMID:24843132

Khokhlova, Tatiana D; Wang, Yak-Nam; Simon, Julianna C; Cunitz, Bryan W; Starr, Frank; Paun, Marla; Crum, Lawrence A; Bailey, Michael R; Khokhlova, Vera A

2014-06-01

24

High Frequency Ultrasound Scattering from Mixtures of two Different Cells Lines: Tissue Characterization Insights  

Microsoft Academic Search

Ultrasound imaging in the most commonly used imaging modality in medicine today. Ultrasound images are based on the echoes received from scattering structures in the human tissues. However, these images are traditionally based on the intensity of the received ultrasound echoes, discarding the information that is present in the frequency dependence of the backscattered waves. In this paper we demonstrate

Michael C. Kolios; Gregory J. Czarnota

2008-01-01

25

CONTRAST-TO-TISSUE RATIO IMPROVEMENT BY TRANSMITTED OPTIMIZED BINARY SIGNAL IN ULTRASOUND PULSE INVERSION IMAGING  

E-print Network

.6556590 ABSTRACT Ultrasound contrast imaging has provided more accurate medical diagnoses. One of the most used. INTRODUCTION Since the 1960s, medical ultrasound imaging has become an essential tool for clinical diagnosisCONTRAST-TO-TISSUE RATIO IMPROVEMENT BY TRANSMITTED OPTIMIZED BINARY SIGNAL IN ULTRASOUND PULSE

Paris-Sud XI, Université de

26

High-frequency ultrasound miniature transducers for tissue imaging  

NASA Astrophysics Data System (ADS)

We have fabricated a miniature 120-MHz transducer for imaging the internal structure of living samples, and mounted it in a 3-mm-diameter rod-shaped probe which ensures contact with a tissue to evaluate the tissue imaging capability of the transducer. The transducer consists of a thin film of 12.5-micrometer thick ZnO sandwiched between two metal electrodes, the bottom one deposited on a sapphire substrate whose other face has a polished concave-sphere acoustic lens. Both the lens diameter and the sphere radius are 0.5 mm; that is, the F number of the lens is 1. The lens of the transducer faces outwards in the probe so that the ultrasound can be transmitted and received directly by it in the radial direction of the rod without any mirrors. As the probe rotates mechanically around its axis and shifts in the direction of the axis, a cylindrical plane created by the locus of the beam focus is located inside of the tissue. Using this scanning, we form tissue images in the C-scan mode in a cylindrical plane within the target tissue. Preliminary results for imaging an in vitro bovine kidney sample into which the probe was inserted demonstrate that the fabricated probe can image microscopic structure inside tissue samples.

Yokosawa, Koichi; Ito, Yukio; Sano, Syuzo; Shinomura, Ryuichi; Sato, Yutaka

1997-04-01

27

The study of cells and tissues Tissues 4 basic types  

E-print Network

Histology The study of cells and tissues #12;Tissues ­ 4 basic types epithelial connective muscular, alveolar, simple, complex #12;Connective Tissues Non-binding Connective Tissue blood/lymph Binding Connective Tissue loose connective tissue dense connective tissue cartilage bone #12;Non-binding Connective

Houde, Peter

28

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. PMID:21680780

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

2011-01-01

29

Ablation of tissue volumes using high intensity focused ultrasound.  

PubMed

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 due to tissue water boiling and acoustic cavitation. Arrays were formed in excised bovine liver. Under some exposure conditions, lesions were found to merge in front of the focal point, and failed to cover the desired volume. Using fine wire manganin-constantan thermocouples, temperature studies revealed a substantial rise in the temperature of surrounding untreated tissue. Cooling curves showed that it was necessary to allow surrounding tissue to cool for up to 2 min before ambient temperature was reached. By allowing the tissue to cool between exposures it was possible to form arrays of overlapping lesions thus successfully ablating the complete target region. PMID:8865561

Malcolm, A L; ter Haar, G R

1996-01-01

30

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

31

The role of acoustic cavitation in enhanced ultrasound- induced heating in a tissue-mimicking phantom  

Microsoft Academic Search

A complete understanding of high-intensity focused ultrasound-induced temperature changes in tissue requires insight into all potential mechanisms for heat deposition. Applications of therapeutic ultrasound often utilize acoustic pressures capable of producing cavitation activity. Recognizing the ability of bubbles to transfer acoustic energy into heat generation, a study of the role bubbles play in tissue hyperthermia becomes necessary. These bubbles are

Patrick Lee Edson

2001-01-01

32

Probability of cavitation for single ultrasound pulses applied to tissues and tissue-mimicking materials  

PubMed Central

In this article, the negative pressure values at which inertial cavitation consistently occurs in response to a single, 2-cycle, focused ultrasound pulse were measured in several media relevant to cavitation-based ultrasound therapy. The pulse was focused into a chamber containing one of the media, which included liquids, tissue-mimicking materials, and ex-vivo canine tissue. Focal waveforms were measured by two separate techniques using a fiber-optic hydrophone. Inertial cavitation was identified by high-speed photography in optically transparent media and an acoustic passive cavitation detector. The probability of cavitation (Pcav) for a single pulse as a function of peak negative pressure (p?) followed a sigmoid curve, with the probability approaching 1 when the pressure amplitude was sufficient. The statistical threshold (defined as Pcav = 0.5) was between p? = 26.0–30.0 MPa in all samples with a high water content, but varied between p? = 13.7 to > 36 MPa for other media. A model for radial cavitation bubble dynamics was employed to evaluate the behavior of cavitation nuclei at these pressure levels. A single bubble nucleus with an inertial cavitation threshold of p? = 28.2 MPa was estimated to have a 2.5 nm radius in distilled water. These data may be valuable for cavitation-based ultrasound therapy to predict the likelihood of cavitation at different pressure levels and dimensions of cavitation-induced lesions in tissue. PMID:23380152

Maxwell, Adam D.; Cain, Charles A.; Hall, Timothy L.; Fowlkes, J. Brian; Xu, Zhen

2012-01-01

33

Focal testicular lesions: colour Doppler ultrasound, contrast-enhanced ultrasound and tissue elastography as adjuvants to the diagnosis  

PubMed Central

The aim of this review is to illustrate the potential of different and newer ultrasound techniques beyond conventional B-mode imaging, including colour Doppler ultrasound, contrast-enhanced ultrasound (CEUS) and tissue elastography, in the characterisation of both benign and malignant intratesticular lesions. Normally, testicular malignancies, either primary or secondary, demonstrate an increase in colour Doppler signal. However, there is a diversity of benign testicular lesions that may mimic testicular malignancies. The use of CEUS improves characterisation of testicular lesions, and confirms lack of vascularity in benign abnormalities such as epidermoid cysts, infarctions, abscesses and changes following trauma. Tissue elastography allows further evaluation of the cellular consistency of the abnormality. Familiarity with the appearances seen with these ultrasound techniques in both benign and malignant abnormalities should aid in improving confidence in arriving at the correct diagnosis. PMID:22674702

Huang, D Y; Sidhu, P S

2012-01-01

34

Reusable tissue-mimicking hydrogel phantoms for focused ultrasound ablation.  

PubMed

The ability of N-isopropylacrylamide (NIPAM)-based hydrogel phantoms to mimic tissues with different acoustic and thermal properties under high-intensity focused ultrasound (HIFU) ablation was investigated. These phantoms were designed to model the formation of thermal lesions in tissues above the threshold temperature of protein denaturation. By adjusting the concentration of acrylic acid (AAc) in the NIPAM-based hydrogel phantoms, the cloud point (i.e., lower critical solution temperature) of the phantoms could be tailored to produce HIFU thermal lesions similar to those formed in different swine tissues in terms of size and shape. Additionally, energy thresholds for inducing transient or permanent bubbles in the phantoms during HIFU ablation were also identified to shed light on the onset of cavitation or material damage. The NIPAM-based hydrogel phantoms developed in this study possess major advantages such as transparent, reusable and tailorable properties, and are practical tools for characterizing an ablative device (or treatment) to determine its efficacy and safety. PMID:25453217

Sun, Ming-Kuan; Shieh, Jay; Lo, Chia-Wen; Chen, Chuin-Shan; Chen, Ben-Ting; Huang, Chang-Wei; Chen, Wen-Shiang

2015-03-01

35

Study of ultrasound stiffness imaging methods using tissue mimicking phantoms.  

PubMed

A pilot study was carried out to investigate the performance of ultrasound stiffness imaging methods namely Ultrasound Elastography Imaging (UEI) and Acoustic Radiation Force Impulse (ARFI) Imaging. Specifically their potential for characterizing different classes of solid mass lesions was analyzed using agar based tissue mimicking phantoms. Composite tissue mimicking phantom was prepared with embedded inclusions of varying stiffness from 50 kPa to 450 kPa to represent different stages of cancer. Acoustic properties such as sound speed, attenuation coefficient and acoustic impedance were characterized by pulse echo ultrasound test at 5 MHz frequency and they are ranged from (1564 ± 88 to 1671 ± 124 m/s), (0.6915 ± 0.123 to 0.8268 ± 0.755 db cm(-1)MHz(-1)) and (1.61 × 10(6) ± 0.127 to 1.76 × 10(6) ± 0.045 kg m(-2)s(-1)) respectively. The elastic property Young's Modulus of the prepared samples was measured by conducting quasi static uni axial compression test under a strain rate of 0.5mm/min upto 10 % strain, and the values are from 50 kPa to 450 kPa for a variation of agar concentration from 1.7% to 6.6% by weight. The composite phantoms were imaged by Siemens Acuson S2000 (Siemens, Erlangen, Germany) machine using linear array transducer 9L4 at 8 MHz frequency; strain and displacement images were collected by UEI and ARFI. Shear wave velocity 4.43 ± 0.35 m/s was also measured for high modulus contrast (18 dB) inclusion and X.XX m/s was found for all other inclusions. The images were pre processed and parameters such as Contrast Transfer Efficiency and lateral image profile were computed and reported. The results indicate that both ARFI and UEI represent the abnormalities better than conventional US B mode imaging whereas UEI enhances the underlying modulus contrast into improved strain contrast. The results are corroborated with literature and also with clinical patient images. PMID:24083832

Manickam, Kavitha; Machireddy, Ramasubba Reddy; Seshadri, Suresh

2014-02-01

36

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. PMID:18334343

Liu, Dalong; Ebbini, Emad S.

2010-01-01

37

Neuropathic tissue responds preferentially to stimulation by intense focused ultrasound  

PubMed Central

We tested the hypothesis that neuropathic tissue is more sensitive to stimulation by intense focused ultrasound (iFU) than control tissue. We created a diffusely neuropathic paw in rats via partial ligation of the sciatic nerve, whose sensitivity to iFU stimulation we compared with sham-surgery and normal control paws. We then applied increasing amounts of iFU (individual 0.2 second pulses at 1.15 MHz) to the rats’ paws, assaying for their reliable withdrawal from that stimulation. Neuropathic rats preferentially withdrew their injured paw from iFU at smaller values of iFU intensity (176 W/cmˆ2 +/- 56) than did sham surgery (217 W/cmˆ2 +/- 25) and normal control (>280 W/cmˆ2) animals, with greater sensitivity and specificity (85% for neuropathic rats and 50% each of sham surgery and normal control rats). These results directly support our hypothesis as well as Gavrilov’s idea that doctors may some day use iFU stimulation to diagnose patients with neuropathies. PMID:23200180

Tych, Rowen E.; Gofeld, Michael; Jarvik, Jeffrey G.; Kliot, Michel; Loeser, John D.; McClintic, Abbi M.; Ollos, Ryan J.; Pederson, Kristin D.; Sparks, Rachel E.; Terman, Gregory W.; Mourad, Pierre D.

2014-01-01

38

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

39

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

40

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

E-print Network

injection of ultrasound contrast agents containing microbubbles has revolutionized medical ultrasoundOptimization of Contrast-to-Tissue Ratio by Adaptation of Transmitted Ternary Signal in Ultrasound, France U 930, Inserm, Tours, France ABSTRACT1 Ultrasound contrast imaging has provided more accurate

Paris-Sud XI, Université de

41

Detection of Multiple Electrical Sources in Tissue Using Ultrasound Current Source Density Imaging  

E-print Network

Detection of Multiple Electrical Sources in Tissue Using Ultrasound Current Source Density Imaging disorders. Ultrasound current source density imaging (UCSDI) is a new technique that maps electrical current electrical current and pressure as acoustic waves propagate through a conducting material. In [4] and [5

Witte, Russell S.

42

Bulk ablation of soft tissue with intense ultrasound: Modeling and experiments  

E-print Network

ablation of soft tissue using intense ultrasound, with potential applications in the thermal treatment. INTRODUCTION Thermal ablation using intense ultrasound is a therapy with potential utility for treatment tumors, a goal of thermal ablation treatments is to reliably cause thermal necrosis in a relatively large

Mast, T. Douglas

43

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

44

Optical and acoustic monitoring of bubble cloud dynamics at a tissue-fluid interface in ultrasound tissue erosion  

PubMed Central

Short, high-intensity ultrasound pulses have the ability to achieve localized, clearly demarcated erosion in soft tissue at a tissue-fluid interface. The primary mechanism for ultrasound tissue erosion is believed to be acoustic cavitation. To monitor the cavitating bubble cloud generated at a tissue-fluid interface, an optical attenuation method was used to record the intensity loss of transmitted light through bubbles. Optical attenuation was only detected when a bubble cloud was seen using high speed imaging. The light attenuation signals correlated well with a temporally changing acoustic backscatter which is an excellent indicator for tissue erosion. This correlation provides additional evidence that the cavitating bubble cloud is essential for ultrasound tissue erosion. The bubble cloud collapse cycle and bubble dissolution time were studied using the optical attenuation signals. The collapse cycle of the bubble cloud generated by a high intensity ultrasound pulse of 4–14 ?s was ~40–300 ?s depending on the acoustic parameters. The dissolution time of the residual bubbles was tens of ms long. This study of bubble dynamics may provide further insight into previous ultrasound tissue erosion results. PMID:17471753

Xu, Zhen; Hall, Timothy L.; Fowlkes, J. Brian; Cain, Charles A.

2009-01-01

45

Focused ultrasound to displace renal calculi: threshold for tissue injury  

PubMed Central

Background The global prevalence and incidence of renal calculi is reported to be increasing. Of the patients that undergo surgical intervention, nearly half experience symptomatic complications associated with stone fragments that are not passed and require follow-up surgical intervention. In a clinical simulation using a clinical prototype, ultrasonic propulsion was proven effective at repositioning kidney stones in pigs. The use of ultrasound to reposition smaller stones or stone fragments to a location that facilitates spontaneous clearance could therefore improve stone-free rates. The goal of this study was to determine an injury threshold under which stones could be safely repositioned. Methods Kidneys of 28 domestic swine were treated with exposures that ranged in duty cycle from 0%–100% and spatial peak pulse average intensities up to 30 kW/cm2 for a total duration of 10 min. The kidneys were processed for morphological analysis and evaluated for injury by experts blinded to the exposure conditions. Results At a duty cycle of 3.3%, a spatial peak intensity threshold of 16,620 W/cm2 was needed before a statistically significant portion of the samples showed injury. This is nearly seven times the 2,400-W/cm2 maximum output of the clinical prototype used to move the stones effectively in pigs. Conclusions The data obtained from this study show that exposure of kidneys to ultrasonic propulsion for displacing renal calculi is well below the threshold for tissue injury. PMID:24921046

2014-01-01

46

Tracking of the advance of the coagulation front in a laser irradiated tissue using ultrasound imaging  

E-print Network

, when it is irradiated by a laser. However, there has been a keen interest to obtain some feedback by experimental means, to better understand the laser-tissue interaction for surgical purposes. Ultrasound imaging techniques are being extensively used...

Jagathesan, Shoban Srikrishna

1993-01-01

47

Biological effects of low frequency high intensity ultrasound application on ex vivo human adipose tissue.  

PubMed

In the present work the effects of a new low frequency, high intensity ultrasound technology on human adipose tissue ex vivo were studied. In particular, we investigated the effects of both external and surgical ultrasound-irradiation (10 min) by evaluating, other than sample weight loss and fat release, also histological architecture alteration as well apoptosis induction. The influence of saline buffer tissue-infiltration on the effects of ultrasound irradiation was also examined. The results suggest that, in our experimental conditions, both transcutaneous and surgical ultrasound exposure caused a significant weight loss and fat release. This effect was more relevant when the ultrasound intensity was set at 100 % (~2.5 W/cm², for external device; ~19-21 W/cm2, for surgical device) compared to 70 % (~1.8 W/cm² for external device; ~13-14 W/cm2 for surgical device). Of note, the effectiveness of ultrasound was much higher when the tissue samples were previously infiltrated with saline buffer, in accordance with the knowledge that ultrasonic waves in aqueous solution better propagate with a consequently more efficient cavitation process. Moreover, the overall effects of ultrasound irradiation did not appear immediately after treatment but persisted over time, being significantly more relevant at 18 h from the end of ultrasound irradiation. Evaluation of histological characteristics of ultrasound-irradiated samples showed a clear alteration of adipose tissue architecture as well a prominent destruction of collagen fibers which were dependent on ultrasound intensity and most relevant in saline buffer-infiltrated samples. The structural changes of collagen bundles present between the lobules of fat cells were confirmed through scanning electron microscopy (SEM) which clearly demonstrated how ultrasound exposure induced a drastic reduction in the compactness of the adipose connective tissue and an irregular arrangement of the fibers with a consequent alteration in the spatial architecture. The analysis of the composition of lipids in the fat released from adipose tissue after ultrasound treatment with surgical device showed, in agreement with the level of adipocyte damage, a significant increase mainly of triglycerides and cholesterol. Finally, ultrasound exposure had been shown to induce apoptosis as shown by the appearance DNA fragmentation. Accordingly, ultrasound treatment led to down-modulation of procaspase-9 expression and an increased level of caspase-3 active form. PMID:21658315

Palumbo, P; Cinque, B; Miconi, G; La Torre, C; Zoccali, G; Vrentzos, N; Vitale, A R; Leocata, P; Lombardi, D; Lorenzo, C; D'Angelo, B; Macchiarelli, G; Cimini, A; Cifone, M G; Giuliani, M

2011-01-01

48

Endoscopic ultrasound guided fine needle tissue acquisition: Where we stand in 2013?  

PubMed Central

Since its introduction, endoscopic ultrasound (EUS) guided fine needle aspiration and fine needle biopsy have become an indispensable tool for the diagnosis of lesions within the gastrointestinal tract and surrounding organs. It has proved to be an effective diagnostic method with high accuracy and low complication rates. Several factors can influence the accuracy and the diagnostic yield of this procedure including experience of the endosonographer, availability of onsite cytopathology services, the method of cytopathology preparation, the location and physical characteristics of the lesion, sampling techniques and the type and size of the needle used. In this review we will outline the recent studies evaluating EUS-guided tissue acquisition and will provide practical recommendations to maximize tissue yield. PMID:24605016

Karadsheh, Zeid; Al-Haddad, Mohammad

2014-01-01

49

Safety and tissue yield for percutaneous native kidney biopsy according to practitioner and ultrasound technique  

PubMed Central

Background Although percutaneous renal biopsy remains an essential tool in the diagnosis and treatment of renal diseases, in recent times the traditional procedure of nephrologists has been performed by non-nephrologists rather than nephrologists at many institutions. The present study assessed the safety and adequacy of tissue yield during percutaneous renal biopsy according to practitioners and techniques based on ultrasound. Methods This study included 658 native renal biopsies performed from 2005 to 2010 at a single centre. The biopsies were performed by nephrologists or expert ultrasound radiologists using the ultrasound-marked blind or real-time ultrasound-guided techniques. Results A total of 271 ultrasound-marked blind biopsies were performed by nephrologists, 170 real-time ultrasound-guided biopsies were performed by nephrologists, and 217 real-time ultrasound-guided biopsies were performed by radiologists during the study period. No differences in post-biopsy complications such as haematoma, need for transfusion and intervention, gross haematuria, pain, or infection were observed among groups. Glomerular numbers of renal specimens from biopsies performed by nephrologists without reference to any technique were higher than those obtained from real-time ultrasound-guided biopsies performed by expert ultrasound radiologists. Conclusions Percutaneous renal biopsy performed by nephrologists was not inferior to that performed by expert ultrasound radiologists as related to specimen yield and post-biopsy complications. PMID:24957046

2014-01-01

50

Modeling transversely isotropic, viscoelastic, incompressible tissue-like materials with application in ultrasound shear wave elastography.  

PubMed

In this paper, we propose a method to model the shear wave propagation in transversely isotropic, viscoelastic and incompressible media. The targeted application is ultrasound-based shear wave elastography for viscoelasticity measurements in anisotropic tissues such as the kidney and skeletal muscles. The proposed model predicts that if the viscoelastic parameters both across and along fiber directions can be characterized as a Voigt material, then the spatial phase velocity at any angle is also governed by a Voigt material model. Further, with the aid of Taylor expansions, it is shown that the spatial group velocity at any angle is close to a Voigt type for weakly attenuative materials within a certain bandwidth. The model is implemented in a finite element code by a time domain explicit integration scheme and shear wave simulations are conducted. The results of the simulations are analyzed to extract the shear wave elasticity and viscosity for both the spatial phase and group velocities. The estimated values match well with theoretical predictions. The proposed theory is further verified by an ex vivo tissue experiment measured in a porcine skeletal muscle by an ultrasound shear wave elastography method. The applicability of the Taylor expansion to analyze the spatial velocities is also discussed. We demonstrate that the approximations from the Taylor expansions are subject to errors when the viscosities across or along the fiber directions are large or the maximum frequency considered is beyond the bandwidth defined by radii of convergence of the Taylor expansions. PMID:25591921

Qiang, Bo; Brigham, John C; Aristizabal, Sara; Greenleaf, James F; Zhang, Xiaoming; Urban, Matthew W

2015-02-01

51

Modeling transversely isotropic, viscoelastic, incompressible tissue-like materials with application in ultrasound shear wave elastography  

NASA Astrophysics Data System (ADS)

In this paper, we propose a method to model the shear wave propagation in transversely isotropic, viscoelastic and incompressible media. The targeted application is ultrasound-based shear wave elastography for viscoelasticity measurements in anisotropic tissues such as the kidney and skeletal muscles. The proposed model predicts that if the viscoelastic parameters both across and along fiber directions can be characterized as a Voigt material, then the spatial phase velocity at any angle is also governed by a Voigt material model. Further, with the aid of Taylor expansions, it is shown that the spatial group velocity at any angle is close to a Voigt type for weakly attenuative materials within a certain bandwidth. The model is implemented in a finite element code by a time domain explicit integration scheme and shear wave simulations are conducted. The results of the simulations are analyzed to extract the shear wave elasticity and viscosity for both the spatial phase and group velocities. The estimated values match well with theoretical predictions. The proposed theory is further verified by an ex vivo tissue experiment measured in a porcine skeletal muscle by an ultrasound shear wave elastography method. The applicability of the Taylor expansion to analyze the spatial velocities is also discussed. We demonstrate that the approximations from the Taylor expansions are subject to errors when the viscosities across or along the fiber directions are large or the maximum frequency considered is beyond the bandwidth defined by radii of convergence of the Taylor expansions.

Qiang, Bo; Brigham, John C.; Aristizabal, Sara; Greenleaf, James F.; Zhang, Xiaoming; Urban, Matthew W.

2015-02-01

52

A tissue velocity ultrasound imaging investigation of the dorsal neck muscles during resisted isometric extension  

Microsoft Academic Search

Persons with neck pain exhibit altered patterns of muscle patterning, but limited investigations have been carried out on these alterations or muscle patterning in healthy volunteers. This study investigated the tissue motion of the dorsal neck muscles at the C4 segmental level in 15 healthy subjects during manually resisted head extension. Doppler-based tissue velocity ultrasound imaging (TVI) was used to

Anneli Peolsson; Lars-Åke Brodin; Michael Peolsson

2010-01-01

53

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

NASA Astrophysics Data System (ADS)

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

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

2007-07-01

54

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

55

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

56

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. PMID:22654643

Jurkonis, R.; Janušauskas, A.; Marozas, V.; Jegelevi?ius, D.; Daukantas, S.; Patašius, M.; Paunksnis, A.; Lukoševi?ius, A.

2012-01-01

57

Shearwave Dispersion Ultrasound Vibrometry (SDUV) for Measuring Tissue Elasticity and Viscosity  

PubMed Central

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 contrast. Shearwave dispersion ultrasound vibrometry (SDUV) uses shear wave propagation speed measured in tissue at multiple frequencies (typically in the range of hundreds of Hertz) to solve quantitatively for both tissue elasticity and viscosity. A shear wave is stimulated within the tissue by an ultrasound push beam and monitored by a separate ultrasound detect beam. The phase difference of the shear wave between 2 locations along its propagation path is used to calculate shear wave speed within the tissue. In vitro SDUV measurements along and across bovine striated muscle fibers show results of tissue elasticity and viscosity close to literature values. An intermittent pulse sequence is developed to allow one array transducer for both push and detect function. Feasibility of this pulse sequence is demonstrated by in vivo SDUV measurements in swine liver using a dual transducer prototype simulating the operation of a single array transducer. PMID:19213632

Chen, Shigao; Urban, Matthew W.; Pislaru, Cristina; Kinnick, Randall; Zheng, Yi; Yao, Aiping; Greenleaf, James F.

2009-01-01

58

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

59

Ultrasound Technologies for the Spatial Patterning of Cells and Extracellular Matrix Proteins and the Vascularization of Engineered Tissue  

NASA Astrophysics Data System (ADS)

Technological advancements in the field of tissue engineering could save the lives of thousands of organ transplant patients who die each year while waiting for donor organs. Currently, two of the primary challenges preventing tissue engineers from developing functional replacement tissues and organs are the need to recreate complex cell and extracellular microenvironments and to vascularize the tissue to maintain cell viability and function. Ultrasound is a form of mechanical energy that can noninvasively and nondestructively interact with tissues at the cell and protein level. In this thesis, novel ultrasound-based technologies were developed for the spatial patterning of cells and extracellular matrix proteins and the vascularization of three-dimensional engineered tissue constructs. Acoustic radiation forces associated with ultrasound standing wave fields were utilized to noninvasively control the spatial organization of cells and cell-bound extracellular matrix proteins within collagen-based engineered tissue. Additionally, ultrasound induced thermal mechanisms were exploited to site-specifically pattern various extracellular matrix collagen microstructures within a single engineered tissue construct. Finally, ultrasound standing wave field technology was used to promote the rapid and extensive vascularization of three-dimensional tissue constructs. As such, the ultrasound technologies developed in these studies have the potential to provide the field of tissue engineering with novel strategies to spatially pattern cells and extracellular matrix components and to vascularize engineered tissue, and thus, could advance the fabrication of functional replacement tissues and organs in the field of tissue engineering.

Garvin, Kelley A.

60

Fine-Needle Biopsy: Should This Be the First Choice in Endoscopic Ultrasound-Guided Tissue Acquisition?  

PubMed Central

Endoscopic ultrasound (EUS)-guided tissue acquisition is an indispensable technique for the diagnosis of many diseases of the gastrointestinal tract and adjacent structures. EUS-guided fine-needle aspiration (EUS-FNA) is known for its high accuracy and low complication rate. However, the outcome of EUS-FNA highly depends on several factors such as the location and characteristics of the lesion, endosonographer's experience, technique of sampling and sample preparation, type and size of the needle used, and presence of a cytopathologist for rapid on-site examination. EUS-guided fine-needle biopsy is useful to obtain core tissue samples with relatively fewer passes. Aspiration of core tissue with preserved architecture is beneficial for the diagnosis of certain diseases and the performance of ancillary testing such as tumor molecular profiling. Issues related to needle size, type, and their acquired samples for cytologic and histologic evaluation are discussed here. PMID:25325002

2014-01-01

61

Ultrasound and Doppler US in Evaluation of Superficial Soft-tissue Lesions.  

PubMed

Improved developments in digital ultrasound technology and the use of high-frequency broadband transducers make ultrasound (US) imaging the first screening tool in investigating superficial tissue lesions. US is a safe (no ionizing radiation), portable, easily repeatable, and cheap form of imaging compared to other imaging modalities. US is an excellent imaging modality to determine the nature of a mass lesion (cystic or solid) and its anatomic relation to adjoining structures. Masses can be characterized in terms of their size, number, component, and vascularity with US and Doppler US especially with power Doppler US. US, however, is operator dependent and has a number of artifacts that can result in misinterpretation. In this review, we emphasize the role of ultrasound, particularly power Doppler, in superficial soft-tissue lesions. PMID:24744969

Toprak, Huseyin; Kiliç, Erkan; Serter, Asli; Kocakoç, Ercan; Ozgocmen, Salih

2014-01-01

62

Detection of magnetic nanoparticles in tissue using magneto-motive ultrasound  

Microsoft Academic Search

The purpose of this study was to demonstrate the magneto-motive ultrasonic detection of superparamagnetic iron oxide (SPIO) nanoparticles as a marker of macrophage recruitment in tissue. The capability of ultrasound to detect SPIO nanoparticles (core diameter ~20 nm) taken up by murine liver macrophages was investigated. Eight mice were sacrificed two days after the intravenous administration of four SPIO doses

Junghwan Oh; Marc D. Feldman; Jeehyun Kim; Chris Condit; Stanislav Emelianov; Thomas E. Milner

2006-01-01

63

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

E-print Network

Ultrasound characterization of red blood cell aggregation with intervening attenuating tissue of aggregating red blood cells reveals information about blood structural properties. The difficulty in applying blood cell (RBC) aggregation.7 It is well known that when RBCs are under low shear rates (

Paris-Sud XI, Université de

64

A Study of Cavitation Activity in Ex vivo Tissue Exposed to High Intensity Focused Ultrasound  

Microsoft Academic Search

Cavitation is often avoided in Focused Ultrasound Surgery (FUS or HIFU) because it can render lesion formation unpredictable. However, cavitation is known to enhance heating. Emissions used as indicators for cavitation activity in ex vivo tissue are not fully understood. This study investigates a wide range of simultaneous acoustic emissions and other potential indicators of cavitation activity. A high frequency

James McLaughlan; Ian Rivens; Gail Ter Haar

2007-01-01

65

Independent component analysis applied to ultrasound speckle texture analysis and tissue characterization.  

PubMed

Analysis of ultrasound speckle texture will provide us information about the underlying properties of tissue, could find applications in early lesion detection and tissue characterization. Traditional first and second order statistics based approaches ignore the higher order statistics information in the texture. On the other hand, conventional multichannel filtering or multiresolution analysis approaches rely on the predefined analytical bases which are not fully adaptive to the data being analyzed. In this paper Independent Component Analysis (ICA), which is based on higher order statistics, is proposed to deal with the ultrasound speckle texture analysis problem. ICA image bases obtained from the training images are applied as a filter bank to the testing images. Then the independent features containing higher order statistics information can be extracted from the marginal distributions of the filtered images. ICA is used here as a dimensionality reduction tool to overcome the difficulty of estimating high dimensional joint density of texture. Support Vector Machine (SVM) is then used as a classifier to classify the tissues. By using the digitally simulated tissues and corresponding B-scan images, we can further correlate the change of tissue microstructure or change of imaging conditions with the change of the ICA feature vectors. Our numerical simulation has shown ICA to be a promising technique for ultrasound speckle texture analysis and tissue characterization compared with some traditional methods such as PCA and Gabor transform. PMID:18003520

Di, Lai; Rao, Navalgund; Kuo, Chung-hui; Bhatt, Shweta; Dogra, Vikram

2007-01-01

66

Ultrasound-modulated optical tomography in soft biological tissues  

E-print Network

, the autocorrelation function becomes4,18 G1(¿) = Z +1 0 p(s)hEs(t)E?s(t+¿)iU hEs(t)E?s(t+¿)iB ds; (3.2) where p(s) is the probability density function of path length s. In Eq. (3.2) we assume that the contributions from Brownian motion (B) and ultrasound (U.... Averaging is over time and over all the photon paths of length s. When the phase 20 variation is small (much less than unity), we can approximate Eq. (3.3) with ›E s(t)E?s(t+¿) fi U = exp[¡F(¿)=2] ; (3.4) where the function F(¿) is F(¿) = *" NX j=1 ¢`n...

Sakadzic, Sava

2007-09-17

67

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

PubMed

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. PMID:22088025

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

2011-11-01

68

Mechanical Model Analysis for Quantitative Evaluation of Liver Fibrosis Based on Ultrasound Tissue Elasticity Imaging  

NASA Astrophysics Data System (ADS)

Precise evaluation of the stage of chronic hepatitis C with respect to fibrosis has become an important issue to prevent the occurrence of cirrhosis and to initiate appropriate therapeutic intervention such as viral eradication using interferon. Ultrasound tissue elasticity imaging, i.e., elastography can visualize tissue hardness/softness, and its clinical usefulness has been studied to detect and evaluate tumors. We have recently reported that the texture of elasticity image changes as fibrosis progresses. To evaluate fibrosis progression quantitatively on the basis of ultrasound tissue elasticity imaging, we introduced a mechanical model of fibrosis progression and simulated the process by which hepatic fibrosis affects elasticity images and compared the results with those clinical data analysis. As a result, it was confirmed that even in diffuse diseases like chronic hepatitis, the patterns of elasticity images are related to fibrous structural changes caused by hepatic disease and can be used to derive features for quantitative evaluation of fibrosis stage.

Shiina, Tsuyoshi; Maki, Tomonori; Yamakawa, Makoto; Mitake, Tsuyoshi; Kudo, Masatoshi; Fujimoto, Kenji

2012-07-01

69

Intense focused ultrasound stimulation can safely stimulate inflamed subcutaneous tissue and assess allodynia  

PubMed Central

Background Potential peripheral sources of deep pain can require invasive evocative tests for their assessment. Here we perform research whose ultimate goal is development of a non-invasive evocative test for deep painful tissue. Methods We used a rat model of inflammation to show that intense focused ultrasound (iFU) differentially stimulates inflamed versus control tissue and can identify allodynia. To do so we applied iFU to inflamed and normal tissue below the skin of rats’ hind paws and measured the amount of ultrasound necessary to induce paw withdrawal. Results iFU of sufficient strength (spatial and temporal average intensities ranged from 100–350 W/cm2) caused the rat to withdraw its inflamed paw, while the same iFU applied to the contralateral paw failed to induce withdrawal, with sensitivity and specificity generally greater than 90%. iFU stimulation of normal tissue required twice the amount of ultrasound to generate a withdrawal than did inflamed tissue, thereby assessing allodynia. Finally, we verified in a preliminary way the safety of iFU stimulation with acute histological studies coupled with mathematical simulations. Conclusions Given that there exist systems to guide iFU deep to the skin, image-guided iFU may one day allow assessment of patient’s deep, peripheral pain generators. PMID:25516804

2014-01-01

70

Mathematical modeling of ultrasound in tissue engineering: From bioreactors to the cellular scale  

NASA Astrophysics Data System (ADS)

Tissue engineering seeks to provide a means to treat injuries that are beyond the body's natural ability to repair without the issues associated with allografts. Autologous cells are cultured in a bioreactor which controls the cellular environment (including mechanical stimulation) for optimal tissue growth. We investigate ultrasound as an effective means of mechanical stimulation by predicting the ultrasonic field in a bioreactor, as well as ultrasonic bioeffects at the cellular level. The Transfer Matrix Angular Spectrum Approach was found to be the most accurate and computationally efficient bioreactor model. Three critical factors influence experimental results: (1) the diameter of the tissue engineering scaffold greatly affects the ultrasonic field; (2) the position of the ultrasonic transducer and liquid level in the tissue culture well determines the maximum pressure amplitude in the bioreactor, but the pressure can be controlled by measuring the transducer input electrical impedance and manipulating the applied voltage; and (3) the position of pressure nodes are influenced by ultrasonic frequency and liquid level; this will affect the response of cells to applied ultrasound. On the cellular level, it was shown that chondrocytes respond to ultrasound with frequency dependence. A predicted resonance frequency near 5MHz matched experimental results showing maximum expression of load inducible genes at 5MHz. Mechanical stresses are concentrated near the nucleus at resonance, alluding to the possibility that the nucleus may directly sense ultrasonic stimulation. We postulate that ultrasound influences the transport of p-ERK to the nucleus or causes minor chromatin reorganization, leading to the observed frequency dependent gene expression. We linked in vitro ultrasonic stimulation to in vivo mechanical stimulation generated by natural movement. The chondrocyte's response to impact is under-damped, and the cell oscillates with a frequency close to the model predicted resonance. It appears that ultrasound applied close to the cell's resonant frequency effectively recreates the mechanical stimulation experienced by cells during natural movement. Ultrasonic bioreactors may therefore reproduce physiological conditions just as well as more complex bioreactors.

Louw, Tobias M.

71

Improved contrast ultrasound with tissue harmonic minimizing pulse.  

PubMed

We have computed predistorted pulses that minimize tissue harmonics to < -25 dB compared to fundamental over a 4-cm depth in the focal region using a Hankel transform-based algorithm. The results indicate their potential in achieving patient independent improvement in contrast with microbubbles using wideband ultrasonic transducers at high mechanical indices. PMID:18334331

Krishnan, Kajoli B; Thomenius, Kai E

2008-01-01

72

Analysis of tissue surrounding thyroid nodules by ultrasound digital images.  

PubMed

Since US is not easily reproducible, the digital image analysis (IA) has been proposed so that the image evaluation is not subjective. In fact, IA meets the criteria of objectivity, accurateness, and reproducibility by a matrix of pixels whose value is displayed in a gray level. This study aims at evaluating via IA the tissue surrounding a thyroid nodule (backyard tissue, BT) from goitres with benign (b-BT) and malignant (m-BT) lesions. Sixty-nine US images of thyroid nodules surrounded by adequate thyroid tissue was classified as normoechoic and homogeneous were enrolled as study group. Forty-three US images from normal thyroid (NT) glands were included as controls. Digital images of 800 × 652 pixels were acquired at a resolution of eight bits with a 256 gray levels depth. By one-way ANOVA, the 43 NT glands were not statistically different (P = 0.91). Mean gray level of normal glands was significantly higher than b-BT (P = 0.026), and m-BT (P = 0.0001), while no difference was found between b-BT and m-BT (P = 0.321). NT tissue boundary external to the nodule was found at 6.0 ± 0.5 mm in cancers and 4.0 ± 0.5 mm in benignancies (P = 0.001). These data should indicate that the tissue surrounding a thyroid nodule may be damaged even when assessed as normal by US. This is of interest to investigate the extranodular effects of thyroid tumors. PMID:24997646

Trimboli, Pierpaolo; Bini, Fabiano; Andrioli, Massimiliano; Giovanella, Luca; Thorel, Maria Francesca; Ceriani, Luca; Valabrega, Stefano; Lenzi, Andrea; Drudi, Francesco Maria; Marinozzi, Franco; Romanelli, Francesco

2014-07-01

73

3-D ultrasound-guided robotic needle steering in biological tissue.  

PubMed

Robotic needle steering systems have the potential to greatly improve medical interventions, but they require new methods for medical image guidance. Three-dimensional (3-D) ultrasound is a widely available, low-cost imaging modality that may be used to provide real-time feedback to needle steering robots. Unfortunately, the poor visibility of steerable needles in standard grayscale ultrasound makes automatic segmentation of the needles impractical. A new imaging approach is proposed, in which high-frequency vibration of a steerable needle makes it visible in ultrasound Doppler images. Experiments demonstrate that segmentation from this Doppler data is accurate to within 1-2 mm. An image-guided control algorithm that incorporates the segmentation data as feedback is also described. In experimental tests in ex vivo bovine liver tissue, a robotic needle steering system implementing this control scheme was able to consistently steer a needle tip to a simulated target with an average error of 1.57 mm. Implementation of 3-D ultrasound-guided needle steering in biological tissue represents a significant step toward the clinical application of robotic needle steering. PMID:25014948

Adebar, Troy K; Fletcher, Ashley E; Okamura, Allison M

2014-12-01

74

Detection of magnetic nanoparticles in tissue using magneto-motive ultrasound  

NASA Astrophysics Data System (ADS)

The purpose of this study was to demonstrate the magneto-motive ultrasonic detection of superparamagnetic iron oxide (SPIO) nanoparticles as a marker of macrophage recruitment in tissue. The capability of ultrasound to detect SPIO nanoparticles (core diameter ~20 nm) taken up by murine liver macrophages was investigated. Eight mice were sacrificed two days after the intravenous administration of four SPIO doses (1.5, 1.0, 0.5, and 0.1 mmol Fe/kg body weight). In the iron-laden livers, ultrasound Doppler measurements showed a frequency shift in response to an applied time-varying magnetic field. M-mode scan and colour power Doppler images of the iron-laden livers also demonstrated nanoparticle movement under focused magnetic field excitation. In the livers of two saline injected control mice, no movement was observed using any ultrasound imaging modes. The results of our experiments indicate that ultrasound imaging of magneto-motive excitation is a candidate imaging modality to identify tissue-based macrophages containing SPIO nanoparticles.

Oh, Junghwan; Feldman, Marc D.; Kim, Jeehyun; Condit, Chris; Emelianov, Stanislav; Milner, Thomas E.

2006-08-01

75

Limited damage of tissue mimic caused by a collapsing bubble under low-frequency ultrasound exposure.  

PubMed

In this study, we investigated the bubble induced serious damage to tissue mimic exposed to 27-kHz ultrasound. The initial bubble radius ranged from 80 to 100 ?m, which corresponded approximately to the experimentally-evaluated resonant radius of the given ultrasound frequency. The tissue mimic consisted of 10 wt% gelatine gel covered with cultured canine kidney epithelial cells. The collapsing bubble behaviour during the ultrasound exposure with negative peak pressures of several hundred kPa was captured by a high-speed camera system. After ultrasound exposure, a cell viability test was conducted based on microscopic bright-field images and fluorescence images for living and dead cells. In the viability test, cells played a role in indicating the damaged area. The bubble oscillations killed the cells, and on occasion detached layers of cultured cells from the gel. The damaged area was comparable or slightly larger than the initial bubble size, and smaller than the maximum bubble size. We concluded that only a small area in close proximity to the bubble could be damaged even above transient cavitation threshold. PMID:24751130

Yoshida, Kenji; Obata, Kazuya; Tsukamoto, Akira; Ushida, Takashi; Watanabe, Yoshiaki

2014-08-01

76

Pulsed cavitational ultrasound therapy for controlled tissue homogenization  

Microsoft Academic Search

Methods were investigated to acoustically control the extent to which cavitation-mediated tissue homogenization is responsible for lesion formation in vitro. These results may guide potential therapeutic procedures that induce damage predominantly via mechanical disruption and, thereby, avoid limitations associated with thermal ablative modalities. Porcine myocardium was insonified at 750 kHz using pulse sequences consisting of high-amplitude pulses (22 MPa Pr)

Jessica E. Parsons; Charles A. Cain; Gerald D. Abrams; J. Brian Fowlkes

2006-01-01

77

Ultrasound  

MedlinePLUS

... findings that might indicate an increased risk for Down syndrome A pregnancy ultrasound may also be done in ... weeks of pregnancy to look for signs of Down syndrome or other problems in the developing baby. This ...

78

Ultrasound  

MedlinePLUS

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

79

Ultrasound  

MedlinePLUS Videos and Cool Tools

... procedure for monitoring the baby’s development in the uterus. Ultrasound uses inaudible sound waves to produce a ... image of the baby while inside the mother’s uterus. The sound waves bounce off solid structures in ...

80

EGFP gene transfection into the synovial joint tissues of rats with rheumatoid arthritis by ultrasound-mediated microbubble destruction  

PubMed Central

The aim of the present study was to explore the feasibility of enhancing green fluorescent protein (EGFP) gene transfection into the synovial joint tissues of rats with rheumatoid arthritis (RA) by ultrasound-mediated microbubble destruction. An optimal SonoVue dose was determined using 40 normal rats categorized into five groups according to the various doses of microbubbles used. At 1 week after ultrasound irradiation, the rats were sacrificed. Damage to the joint synovial tissues was observed with hematoxylin and eosin histopathological staining under a microscope. A further 44 normal rats were used to establish a rat model of RA, and were then categorized into four groups: EGFP, ultrasound + EGFP, microbubbles + EGFP and ultrasound + microbubbles + EGFP. The last group was irradiated with ultrasound for 10 min following the injection of 300 ?l SonoVue and 10 ?g EGFP into the joint cavity. Rats were sacrificed after 3 days and synovial tissue was collected from the knee joints for observation of EGFP with fluorescence microscopy and analysis by quantitative polymerase chain reaction. EGFP expression was observed in the synovial tissues of all groups. However, high EGFP expression levels were observed in the ultrasound + microbubbles + EGFP group. No statistically significant differences (P>0.05) were observed in the EGFP expression levels between the EGFP, ultrasound + EGFP and microbubbles + EGFP groups. However, EGFP expression levels in the EGFP, ultrasound + EGFP and microbubbles + EGFP groups significantly differed (P<0.05) from that in the ultrasound + microbubbles + EGFP group. Therefore, ultrasound-mediated microbubble destruction improved EGFP transfection efficiency into the joint synovial tissues of rats with RA. PMID:24940446

JING, XIANG-XIANG; LIU, JIE; YANG, BING-ANG; FU, SHAO-QING; WU, TANG-NA; WANG, DONG-LIN

2014-01-01

81

Novel tissue mimicking materials for high frequency breast ultrasound phantoms.  

PubMed

The development and acoustical characterisation of a range of novel agar-based tissue mimicking material (TMMs) for use in clinically relevant, quality assurance (QA) and anthropomorphic breast phantoms are presented. The novel agar-based TMMs described in this study are based on a comprehensive, systematic variation of the ingredients in the International Electrotechnical Commission (IEC) TMM. A novel, solid fat-mimicking material was also developed and acoustically characterised. Acoustical characterisation was carried out using an in-house scanning acoustic macroscope at low (7.5 MHz) and high frequencies (20 MHz), using the pulse-echo insertion technique. The speeds of sound range from 1490 to 1570 m. s(-1), attenuation coefficients range from 0.1 to 0.9 dB. cm(?1). MHz(-1) and relative backscatter ranges from 0 to -20 dB. It was determined that tissues can be mimicked in terms of independently controllable speeds of sound and attenuation coefficients. These properties make these novel TMMs suitable for use in clinically relevant QA and anthropomorphic phantoms and would potentially be useful for other high frequency applications such as intravascular and small animal imaging. PMID:21084158

Cannon, Louise M; Fagan, Andrew J; Browne, Jacinta E

2011-01-01

82

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

PubMed Central

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

2012-01-01

83

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

PubMed

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 approximately 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. PMID:15104313

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

2004-03-21

84

New denoising technique for ultrasound images using morphological properties of speckle combined with tissue classifying parameters  

NASA Astrophysics Data System (ADS)

In this paper we introduce a new speckle suppression technique for medical ultrasound images that incorporates morphological properties of speckle as well as tissue classifying parameters. Each individual speckles is located, and, exploiting our prior knowledge on the tissue classification, it is determined whether this speckle is noise or a medically relevant detail. We apply the technique on images of neonatal brains affected by White Matter Damage (leukomalacia). The results show that applying an active contour on a processed image, in order to segment the affected areas, yields a segmentation much closer to that of an expert.

Stippel, Gjenna; Philips, Wilfried R.; Lemahieu, Ignace L.

2002-04-01

85

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

86

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

2013-10-01

87

TOMOGRAPHIC RECONSTRUCTION OF TISSUE PROPERTIES AND TEMPERATURE INCREASE FOR HIGH-INTENSITY FOCUSED ULTRASOUND APPLICATIONS  

PubMed Central

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

2013-01-01

88

Ultrasound-guided three-dimensional needle steering in biological tissue with curved surfaces.  

PubMed

In this paper, we present a system capable of automatically steering a bevel-tipped flexible needle under ultrasound guidance toward a physical target while avoiding a physical obstacle embedded in gelatin phantoms and biological tissue with curved surfaces. An ultrasound pre-operative scan is performed for three-dimensional (3D) target localization and shape reconstruction. A controller based on implicit force control is developed to align the transducer with curved surfaces to assure the maximum contact area, and thus obtain an image of sufficient quality. We experimentally investigate the effect of needle insertion system parameters such as insertion speed, needle diameter and bevel angle on target motion to adjust the parameters that minimize the target motion during insertion. A fast sampling-based path planner is used to compute and periodically update a feasible path to the target that avoids obstacles. We present experimental results for target reconstruction and needle insertion procedures in gelatin-based phantoms and biological tissue. Mean targeting errors of 1.46±0.37mm, 1.29±0.29mm and 1.82±0.58mm are obtained for phantoms with inclined, curved and combined (inclined and curved) surfaces, respectively, for insertion distance of 86-103mm. The achieved targeting errors suggest that our approach is sufficient for targeting lesions of 3mm radius that can be detected using clinical ultrasound imaging systems. PMID:25455165

Abayazid, Momen; Moreira, Pedro; Shahriari, Navid; Patil, Sachin; Alterovitz, Ron; Misra, Sarthak

2015-01-01

89

New effects in absorption of ultrasound in intermediate state of high pure type I superconductor  

E-print Network

The research on the longitudinal ultrasound absorption in an intermediate state of the high pure Gallium single crystal at the frequency of 50-190MHz at the temperatures of 0,37-0,75 K, using the impulse method, is conducted. The new effects in the absorption of ultrasound in an intermediate state of the high pure type I superconductor are discovered. The big oscillations in the dependence of the ultrasound absorption on the magnetic field in an intermediate state of the high pure Gallium single crystal are experimentally observed at the magnitudes of magnetic field below the critical magnetic field. The maximum of the monotonic absorption of longitudinal ultrasound in an intermediate state of the high pure type I superconductor is also obtained. The possible original theoretical mechanisms to explain the nature of big oscillations in the dependence of the ultrasound absorption on the magnetic field in an intermediate state of the high pure type I superconductor are proposed.

Shepelev, Anatoly G; Filimonov, Genady D

2012-01-01

90

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 ...

91

Deep-tissue focal fluorescence imaging with digitally time-reversed ultrasound-encoded light  

PubMed Central

Fluorescence imaging is one of the most important research tools in biomedical sciences. However, scattering of light severely impedes imaging of thick biological samples beyond the ballistic regime. Here we directly show focusing and high-resolution fluorescence imaging deep inside biological tissues by digitally time-reversing ultrasound-tagged light with high optical gain (~5×105). We confirm the presence of a time-reversed optical focus along with a diffuse background—a corollary of partial phase conjugation—and develop an approach for dynamic background cancellation. To illustrate the potential of our method, we image complex fluorescent objects and tumour microtissues at an unprecedented depth of 2.5 mm in biological tissues at a lateral resolution of 36 ?m×52 ?m and an axial resolution of 657 ?m. Our results set the stage for a range of deep-tissue imaging applications in biomedical research and medical diagnostics. PMID:22735456

Wang, Ying Min; Judkewitz, Benjamin; DiMarzio, Charles A.; Yang, Changhuei

2012-01-01

92

Synergistic ablation of liver tissue and liver cancer cells with high-intensity focused ultrasound and ethanol.  

PubMed

We investigated the combined effect of ethanol and high-intensity focused ultrasound (HIFU), first, on heating and cavitation bubble activity in tissue-mimicking phantoms and porcine liver tissues and, second, on the viability of HepG2 liver cancer cells. Phantoms or porcine tissues were injected with ethanol and then subjected to HIFU at acoustic power ranging from 1.2 to 20.5 W (HIFU levels 1-7). Cavitation events and the temperature around the focal zone were measured with a passive cavitation detector and embedded type K thermocouples, respectively. HepG2 cells were subjected to 4% ethanol solution in growth medium (v/v) just before the cells were exposed to HIFU at 2.7, 8.7 or 12.0 W for 30 s. Cell viability was measured 2, 24 and 72 h post-treatment. The results indicate that ethanol and HIFU have a synergistic effect on liver cancer ablation as manifested by greater temperature rise and lesion volume in liver tissues and reduced viability of liver cancer cells. This effect is likely caused by reduction of the cavitation threshold in the presence of ethanol and the increased rate of ethanol diffusion through the cell membrane caused by HIFU-induced streaming, sonoporation and heating. PMID:24798386

Hoang, Nguyen H; Murad, Hakm Y; Ratnayaka, Sithira H; Chen, Chong; Khismatullin, Damir B

2014-08-01

93

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

94

Interlaced photoacoustic and ultrasound imaging system with real-time coregistration for ovarian tissue characterization  

NASA Astrophysics Data System (ADS)

Coregistered ultrasound (US) and photoacoustic imaging are emerging techniques for mapping the echogenic anatomical structure of tissue and its corresponding optical absorption. We report a 128-channel imaging system with real-time coregistration of the two modalities, which provides up to 15 coregistered frames per second limited by the laser pulse repetition rate. In addition, the system integrates a compact transvaginal imaging probe with a custom-designed fiber optic assembly for in vivo detection and characterization of human ovarian tissue. We present the coregistered US and photoacoustic imaging system structure, the optimal design of the PC interfacing software, and the reconfigurable field programmable gate array operation and optimization. Phantom experiments of system lateral resolution and axial sensitivity evaluation, examples of the real-time scanning of a tumor-bearing mouse, and ex vivo human ovaries studies are demonstrated.

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

2014-07-01

95

Interlaced photoacoustic and ultrasound imaging system with real-time coregistration for ovarian tissue characterization.  

PubMed

Coregistered ultrasound (US) and photoacoustic imaging are emerging techniques for mapping the echogenic anatomical structure of tissue and its corresponding optical absorption. We report a 128-channel imaging system with real-time coregistration of the two modalities, which provides up to 15 coregistered frames per second limited by the laser pulse repetition rate. In addition, the system integrates a compact transvaginal imaging probe with a custom-designed fiber optic assembly for in vivo detection and characterization of human ovarian tissue. We present the coregistered US and photoacoustic imaging system structure, the optimal design of the PC interfacing software, and the reconfigurable field programmable gate array operation and optimization. Phantom experiments of system lateral resolution and axial sensitivity evaluation, examples of the real-time scanning of a tumor-bearing mouse, and ex vivo human ovaries studies are demonstrated. PMID:25069009

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

2014-07-01

96

Lesions in Porcine Liver Tissues Created by Continuous High Intensity Ultrasound Exposures in Vitro  

NASA Astrophysics Data System (ADS)

Lesions in porcine liver tissues created by continuous high intensity focused ultrasound (HIFU) exposures in vitro are theoretically and experimentally investigated, with the transmitter moving along a linear path at a fixed speed. Numerical simulations of the lesion formation are performed based on the Khokhlov—Zabolotskaya—Kuznetov equation and the bio-heat equation. In order to verify the theoretical predictions, experiments are performed in the one-dimensional scanning mode to measure the cross-sectional area of lesions created in the in vitro porcine liver exposed to 1.01-MHz HIFU pulses with the acoustic power of 70 W. The results indicate that, compared to the traditional discrete treatment protocol, the application of a continuous scanning model can create more uniform lesions in tissues and significantly reduces the total treatment time from 47s to 30s.

Zhang, Zhe; Chen, Tao; Zhang, Dong

2013-02-01

97

Ultrasound beam simulations in inhomogeneous tissue geometries using the hybrid angular spectrum method.  

PubMed

The angular spectrum method is a fast, accurate and computationally efficient method for modeling wave propagation. However, the traditional angular spectrum method assumes that the region of propagation has homogenous properties. In this paper, the angular spectrum method is extended to calculate ultrasound wave propagation in inhomogeneous tissue geometries, important for clinical efficacy, patient safety, and treatment reliability in MR-guided focused ultrasound surgery. The inhomogeneous tissue region to be modeled is segmented into voxels, each voxel having a unique speed of sound, attenuation coefficient, and density. The pressure pattern in the 3-D model is calculated by alternating between the space domain and the spatial-frequency domain for each plane of voxels in the model. The new technique was compared with the finite-difference time-domain technique for a model containing attenuation, refraction, and reflection and for a segmented human breast model; although yielding essentially the same pattern, it results in a reduction in calculation times of at least two orders of magnitude. PMID:22711405

Vyas, Urvi; Christensen, Douglas

2012-06-01

98

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

99

Considering Angle Selection When Using Ultrasound Electrode Displacement Elastography to Evaluate Radiofrequency Ablation of Tissues  

PubMed Central

Percutaneous radiofrequency ablation (RFA) is a minimally invasive treatment to thermally destroy tumors. Ultrasound-based electrode-displacement elastography is an emerging technique for evaluating the region of RFA-induced lesions. The angle between the imaging probe and the RFA electrode can influence electrode-displacement elastography when visualizing the ablation zone. We explored the angle effect on electrode-displacement elastography to measure the ablation zone. Phantoms embedded with meatballs were fabricated and then ablated using an RFA system to simulate RFA-induced lesions. For each phantom, a commercial ultrasound scanner with a 7.5?MHz linear probe was used to acquire raw image data at different angles, ranging from 30° to 90° at increments of 10°, to construct electrode-displacement images and facilitate comparisons with tissue section images. The results revealed that the ablation regions detected using electrode-displacement elastography were highly correlated with those from tissue section images when the angle was between 30° and 60°. However, the boundaries of lesions were difficult to distinguish, when the angle was larger than 60°. The experimental findings suggest that angle selection should be considered to achieve reliable electrode-displacement elastography to describe ablation zones. PMID:24971347

Li, Qiang; Chen, Pin-Yu; Wang, Chiao-Yin; Liu, Hao-Li; Teng, Jianfu

2014-01-01

100

Ex Vivo characterization of canine liver tissue viscoelasticity after high-intensity focused ultrasound ablation.  

PubMed

The potential of elasticity imaging to detect high-intensity focused ultrasound (HIFU) lesions on the basis of their distinct biomechanical properties is promising. However, information on the quantitative mechanical properties of the tissue and the optimal intensity at which to determine the best contrast parameters is scarce. In this study, fresh canine livers were ablated using combinations of ISPTA intensities of 5.55, 7.16 and 9.07 kW/cm(2) and durations of 10 and 30 s ex vivo, resulting in six groups of ablated tissues. Biopsy samples were then interrogated using dynamic shear mechanical testing within the range of 0.1-10 Hz to characterize the tissue's post-ablation viscoelastic properties. All mechanical parameters were found to be frequency dependent. Compared with unablated cases, all six groups of ablated tissues had statistically significant higher complex shear modulus and shear viscosity. However, among the ablated groups, both complex shear modulus and shear viscosity were found to monotonically increase in groups 1-4 (5.55 kW/cm(2) for 10 s, 7.16 kW/cm(2) for 10 s, 9.07 kW/cm(2) for 10 s, and 5.55 kW/cm(2) for 30 s, respectively), but to decrease in groups 5 and 6 (7.16 kW/cm(2) for 30 s, and 9.07 kW/cm(2) for 30 s, respectively). For groups 5 and 6, the temperature was expected to exceed the boiling point, and therefore, the decreased stiffening could be due to the compromised integrity of the tissue microstructure. Future studies will entail estimation tissue mechanical properties in vivo and perform real-time monitoring of tissue alterations during ablation. PMID:24315395

Shahmirzadi, Danial; Hou, Gary Y; Chen, Jiangang; Konofagou, Elisa E

2014-02-01

101

Biomechanics-Based Curvature Estimation for Ultrasound-guided Flexible Needle Steering in Biological Tissues.  

PubMed

Needle-based procedures are commonly performed during minimally invasive surgery for treatment and diagnosis. Accurate needle tip placement is important for the success of the procedures. Misplacement of the needle tip might cause unsuccessful treatment or misdiagnosis. Robot-assisted needle insertion systems have been developed in order to steer flexible bevel-tipped needles. However, current systems depend on the information of maximum needle curvature, which is estimated by performing prior insertions. This work presents a new three-dimensional flexible needle steering system which integrates an optimal steering control, ultrasound-based needle tracking system, needle deflection model, online needle curvature estimation and offline curvature estimation based on biomechanics properties. The online and the offline curvature estimations are used to update the steering control in real time. The system is evaluated by experiments in gelatin phantoms and biological tissues (chicken breast tissues). The average targeting error in gelatin phantoms is 0.42 ± 0.17 mm, and in biological tissues is 1.63 ± 0.29 mm. The system is able to accurately steer a flexible needle in multi-layer phantoms and biological tissues without performing prior insertions to estimate the maximum needle curvature. PMID:25465619

Moreira, Pedro; Misra, Sarthak

2014-12-01

102

Prediction of Difficult Laryngoscopy in Obese Patients by Ultrasound Quantification of Anterior Neck Soft Tissue1  

PubMed Central

Prediction of difficult laryngoscopy in obese patients is challenging. In 50 morbidly obese patients, we quantified the neck soft tissue from skin to anterior aspect of trachea at the vocal cords using ultrasound. Thyromental distance <6 cm, mouth opening <4 cm, limited neck mobility, Mallampati score >2, abnormal upper teeth, neck circumference >45 cm, and sleep apnoea were considered predictors of difficult laryngoscopy. Of the nine (18%) difficult laryngoscopy cases, seven had obstructive sleep apnoea history; whereas, only 2 of the 41 easy laryngoscopy patients did (P<0.001). Difficult laryngoscopy patients had larger neck circumference [50 (3.8) vs. 43.5 (2.2) cm; P<0.001] and more pre-tracheal soft tissue [28 (2.7) mm vs. 17.5 (1.8) mm; P<0.001] [mean (SD)]. Soft tissue values completely separated difficult and easy laryngoscopies. None of the other predictors correlated with difficult laryngoscopy. Thus, an abundance of pretracheal soft tissue at the level of vocal cords is a good predictor of difficult laryngoscopy in obese patients. PMID:14616599

Ezri, T.; Gewürtz, G.; Sessler, D.I.; Medalion, B.; Szmuk, P.; Hagberg, C.; Susmallian, S.

2005-01-01

103

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

104

Comparison of three models at high frequency for ultrasound tissue scattering  

NASA Astrophysics Data System (ADS)

A mammary carcinoma was grown in mice and imaged with an ultrasound transducer operating with a center frequency of 65 MHz. Quantitative ultrasound (QUS) analysis was used to characterize the tumors using the bandwidth of 30 to 85 MHz. Three models (Gaussian scatterer, fluid-filled sphere, and a new cell scatterer) for scattering were examined and scatterer property estimates were compared to real tissue morphology as seen from optical microscope images of the tumors. The Gaussian scattering model did not fit the data well compared to the fluid-filled sphere and new cell scatterer models. The fluid-filled sphere model fit the measurements better than any other model but did not yield scatterer property estimates that resembled underlying structure. Using the fluid-filled sphere model, the average estimated scatterer diameter was 25.5+/-0.14 ?m. A new cell scatterer model was developed, which was based on scattering from a cell by incorporating the effects of the cytoskeleton and nucleus. The new cell scatterer model yielded estimates that appeared to reflect underlying structure more accurately. Using the new cell scatterer model, the average estimated nuclear diameter was 15.6+/-2.2 ?m compared with 13.2 ?m as measured from optical microscope images.

Oelze, Michael; O'Brien, William; Zachary, James

2005-04-01

105

Paraffin-gel tissue-mimicking material for ultrasound-guided needle biopsy phantom.  

PubMed

Paraffin-gel waxes have been investigated as new soft tissue-mimicking materials for ultrasound-guided breast biopsy training. Breast phantoms were produced with a broad range of acoustical properties. The speed of sound for the phantoms ranged from 1425.4 ± 0.6 to 1480.3 ± 1.7 m/s at room temperature. The attenuation coefficients were easily controlled between 0.32 ± 0.27 dB/cm and 2.04 ± 0.65 dB/cm at 7.5 MHz, depending on the amount of carnauba wax added to the base material. The materials do not suffer dehydration and provide adequate needle penetration, with a Young's storage modulus varying between 14.7 ± 0.2 kPa and 34.9 ± 0.3 kPa. The phantom background material possesses long-term stability and can be employed in a supine position without changes in geometry. These results indicate that paraffin-gel waxes may be promising materials for training radiologists in ultrasound biopsy procedures. PMID:24035622

Vieira, Sílvio L; Pavan, Theo Z; Junior, Jorge E; Carneiro, Antonio A O

2013-12-01

106

Estimating dynamic changes of tissue attenuation coefficient during high-intensity focused ultrasound treatment  

PubMed Central

Background This study investigated the dynamic changes of tissue attenuation coefficients before, during, and after high-intensity focused ultrasound (HIFU) treatment at different total acoustic powers (TAP) in ex vivo porcine muscle tissue. It further assessed the reliability of employing changes in tissue attenuation coefficient parameters as potential indicators of tissue thermal damage. Methods Two-dimensional pulse-echo radio frequency (RF) data were acquired before, during, and after HIFU exposure to estimate changes in least squares attenuation coefficient slope (??) and attenuation coefficient intercept (??0). Using the acquired RF data, ?? and ??0 images, along with conventional B-mode ultrasound images, were constructed. The dynamic changes of ?? and ??0, averaged in the region of interest, were correlated with B-mode images obtained during the HIFU treatment process. Results At a HIFU exposure duration of 40 s and various HIFU intensities (737–1,068 W/cm2), ?? and ??0 increased rapidly to values in the ranges 1.5–2.5 dB/(MHz.cm) and 4–5 dB/cm, respectively. This rapid increase was accompanied with the appearance of bubble clouds in the B-mode images. Bubble activities appeared as strong hyperechoic regions in the B-mode images and caused fluctuations in the estimated ?? and ??0 values. After the treatment, ?? and ??0 values gradually decreased, accompanied by fade-out of hyperechoic spots in the B-mode images. At 10 min after the treatment, they reached values in ranges 0.75–1 dB/(MHz.cm) and 1–1.5 dB/cm, respectively, and remained stable within those ranges. At a long HIFU exposure duration of around 10 min and low HIFU intensity (117 W/cm2), ?? and ??0 gradually increased to values of 2.2 dB/(MHz.cm) and 2.2 dB/cm, respectively. This increase was not accompanied with the appearance of bubble clouds in the B-mode images. After HIFU treatment, ?? and ??0 gradually decreased to values of 1.8 dB/(MHz.cm) and 1.5 dB/cm, respectively, and remained stable at those values. Conclusions ?? and ??0 estimations were both potentially reliable indicators of tissue thermal damage. In addition, ?? and ??0 images both had significantly higher contrast-to-speckle ratios compared to the conventional B-mode images and outperformed the B-mode images in detecting HIFU thermal lesions at all investigated TAPs and exposure durations. PMID:25516802

2013-01-01

107

High resolution imaging beyond the acoustic diffraction limit in deep tissue via ultrasound-switchable NIR fluorescence  

PubMed Central

Fluorescence imaging in deep tissue with high spatial resolution is highly desirable because it can provide details about tissue's structural, functional, and molecular information. Unfortunately, current fluorescence imaging techniques are limited either in penetration depth (microscopy) or spatial resolution (diffuse light based imaging) as a result of strong light scattering in deep tissue. To overcome this limitation, we developed an ultrasound-switchable fluorescence (USF) imaging technique whereby ultrasound was used to switch on/off the emission of near infrared (NIR) fluorophores. We synthesized and characterized unique NIR USF contrast agents. The excellent switching properties of these agents, combined with the sensitive USF imaging system developed in this study, enabled us to image fluorescent targets in deep tissue with spatial resolution beyond the acoustic diffraction limit. PMID:24732947

Pei, Yanbo; Wei, Ming-Yuan; Cheng, Bingbing; Liu, Yuan; Xie, Zhiwei; Nguyen, Kytai; Yuan, Baohong

2014-01-01

108

Abstract -A new methodology has been described using ultra-sound to possibly quantify the soft tissue artifact introduced in  

E-print Network

Abstract - A new methodology has been described using ultra- sound to possibly quantify the soft for computer based surgical sys- tems. Ultrasound is an affordable and portable imaging modali- ty which could as a possible ad-hoc exercise to model the trajectory of displace- ment to compensate for the soft tissue errors

Lee, WonSook

109

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

110

Hybrid optoacoustic and ultrasound biomicroscopy monitors’ laser-induced tissue modifications and magnetite nanoparticle impregnation  

NASA Astrophysics Data System (ADS)

Tissue modification under laser radiation is emerging as one of the advanced applications of lasers in medicine, with treatments ranging from reshaping and regeneration of cartilage to normalization of the intraocular pressure. Laser-induced structural alterations can be studied using conventional microscopic techniques applied to thin specimen. Yet, development of non-invasive imaging methods for deep tissue monitoring of structural alterations under laser radiation is of great importance, especially for attaining efficient feedback during the procedures. We developed a fast scanning biomicroscopy system that can simultaneously deliver both optoacoustic and pulse-echo ultrasound contrast from intact tissues and show that both modalities allow manifesting the laser-induced changes in cartilage and sclera. Furthermore, images of the sclera samples reveal a crater developing around the center of the laser-irradiated spot as well as a certain degree of thickening within the treated zone, presumably due to pore formation. Finally, we were able to observe selective impregnation of magnetite nanoparticles into the cartilage, thus demonstrating a possible contrast enhancement approach for studying specific treatment effects. Overall, the new imaging approach holds promise for development of noninvasive feedback control systems that could guarantee efficacy and safety of laser-based medical procedures.

Estrada, Héctor; Sobol, Emil; Baum, Olga; Razansky, Daniel

2014-12-01

111

Dual-mode registration of dynamic contrast-enhanced ultrasound combining tissue and contrast sequences.  

PubMed

This study proposes a new method for automatic, iterative image registration in the context of dynamic contrast-enhanced ultrasound (DCE-US) imaging. By constructing a cost function of image registration using a combination of the tissue and contrast-microbubble responses, this new method, referred to as dual-mode registration, performs alignment based on both tissue and vascular structures. Data from five focal liver lesions (FLLs) were used for the evaluation. Automatic registration based on the dual-mode registration technique and tissue-mode registration obtained using the linear response image sequence alone were compared to manual alignment of the sequence by an expert. Comparison of the maximum distance between the transformations applied by the automatic registration techniques and those from expert manual registration reference showed that the dual-mode registration provided better precision than the tissue-mode registration for all cases. The reduction of maximum distance ranged from 0.25 to 9.3mm. Dual-mode registration is also significantly better than tissue-mode registration for the five sequences with p-values lower than 0.03. The improved sequence alignment is also demonstrated visually by comparison of images from the sequences and the video playbacks of the motion-corrected sequences. This new registration technique better maintains a selected region of interest (ROI) within a fixed position of the image plane throughout the DCE-US sequence. This should reduce motion-related variability of the echo-power estimations and, thus, contribute to more robust perfusion quantification with DCE-US. PMID:24529339

Bouhlel, Nizar; Coron, Alain; Barrois, Guillaume; Lucidarme, Olivier; Bridal, S Lori

2014-07-01

112

Contrast-enhanced ultrasound analysis of tissue perfusion in tumor-bearing mice following treatment with endostatin combined with radiotherapy  

PubMed Central

The aim of this study was to observe the effects of Endostar (recombinant human endostatin) and radiotherapy, singly or in combination, on blood flow in mouse tumour tissue using ultrasound imaging. The ultrasound contrast agent, SonoVue, was used for the contrast-enhanced ultrasound examinations. SonoLiver software was used to analyse dynamic vascular patterns (DVPs) in the contrast process. Blood perfusion data were collected and statistical analysis was performed for data processing. Results were presented as DVP curves and quantitative parameters. Quantitative parameters showed statistically significant (P<0.05) differences in peak strength, rise time, time to peak and mean transit time among the various treatment groups. Changes in tumour blood perfusion were quantified by the assessment of contrast-enhanced ultrasound parameters. The results indirectly reflected the degree of change in angiogenesis in the tumour following experimental intervention. Ultrasound contrast imaging effectively showed the extent of the changes in vascularity and flow state. Therefore, contrast-enhanced ultrasound is suitable for use as an indicator of blood flow changes in an experimental model. PMID:24940439

GE, WEI; ZHENG, YONGFA; TAO, ZEZHANG

2014-01-01

113

Contrast-enhanced ultrasound analysis of tissue perfusion in tumor-bearing mice following treatment with endostatin combined with radiotherapy.  

PubMed

The aim of this study was to observe the effects of Endostar (recombinant human endostatin) and radiotherapy, singly or in combination, on blood flow in mouse tumour tissue using ultrasound imaging. The ultrasound contrast agent, SonoVue, was used for the contrast-enhanced ultrasound examinations. SonoLiver software was used to analyse dynamic vascular patterns (DVPs) in the contrast process. Blood perfusion data were collected and statistical analysis was performed for data processing. Results were presented as DVP curves and quantitative parameters. Quantitative parameters showed statistically significant (P<0.05) differences in peak strength, rise time, time to peak and mean transit time among the various treatment groups. Changes in tumour blood perfusion were quantified by the assessment of contrast-enhanced ultrasound parameters. The results indirectly reflected the degree of change in angiogenesis in the tumour following experimental intervention. Ultrasound contrast imaging effectively showed the extent of the changes in vascularity and flow state. Therefore, contrast-enhanced ultrasound is suitable for use as an indicator of blood flow changes in an experimental model. PMID:24940439

Ge, Wei; Zheng, Yongfa; Tao, Zezhang

2014-05-01

114

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

2013-08-01

115

Pulsed ultrasound enhances the delivery of nitric oxide from bubble liposomes to ex vivo porcine carotid tissue  

PubMed Central

Ultrasound-mediated drug delivery is a novel technique for enhancing the penetration of drugs into diseased tissue beds noninvasively. By encapsulating drugs into microsized and nanosized liposomes, the therapeutic can be shielded from degradation within the vasculature until delivery to a target site by ultrasound exposure. Traditional in vitro or ex vivo techniques to quantify this delivery profile include optical approaches, cell culture, and electrophysiology. Here, we demonstrate an approach to characterize the degree of nitric oxide (NO) delivery to porcine carotid tissue by direct measurement of ex vivo vascular tone. An ex vivo perfusion model was adapted to assess ultrasound-mediated delivery of NO. This potent vasodilator was coencapsulated with inert octafluoropropane gas to produce acoustically active bubble liposomes. Porcine carotid arteries were excised post mortem and mounted in a physiologic buffer solution. Vascular tone was assessed in real time by coupling the artery to an isometric force transducer. NO-loaded bubble liposomes were infused into the lumen of the artery, which was exposed to 1 MHz pulsed ultrasound at a peak-to-peak acoustic pressure amplitude of 0.34 MPa. Acoustic cavitation emissions were monitored passively. Changes in vascular tone were measured and compared with control and sham NO bubble liposome exposures. Our results demonstrate that ultrasound-triggered NO release from bubble liposomes induces potent vasorelaxation within porcine carotid arteries (maximal relaxation 31%±8%), which was significantly stronger than vasorelaxation due to NO release from bubble liposomes in the absence of ultrasound (maximal relaxation 7%±3%), and comparable with relaxation due to 12 ?M sodium nitroprusside infusions (maximal relaxation 32%±3%). This approach is a valuable mechanistic tool for assessing the extent of drug release and delivery to the vasculature caused by ultrasound. PMID:25336947

Sutton, JT; Raymond, JL; Verleye, MC; Pyne-Geithman, GJ; Holland, CK

2014-01-01

116

Implementation of a Rotational Ultrasound Biomicroscopy System Equipped with a High-Frequency Angled Needle Transducer — Ex Vivo Ultrasound Imaging of Porcine Ocular Posterior Tissues  

PubMed Central

The mechanical scanning of a single element transducer has been mostly utilized for high-frequency ultrasound imaging. However, it requires space for the mechanical motion of the transducer. In this paper, a rotational scanning ultrasound biomicroscopy (UBM) system equipped with a high-frequency angled needle transducer is designed and implemented in order to minimize the space required. It was applied to ex vivo ultrasound imaging of porcine posterior ocular tissues through a minimal incision hole of 1 mm in diameter. The retina and sclera for the one eye were visualized in the relative rotating angle range of 270° ? 330° and at a distance range of 6 ? 7 mm, whereas the tissues of the other eye were observed in relative angle range of 160° ? 220° and at a distance range of 7.5 ? 9 mm. The layer between retina and sclera seemed to be bent because the distance between the transducer tip and the layer was varied while the transducer was rotated. Certin features of the rotation system such as the optimal scanning angle, step angle and data length need to be improved for ensure higher accuracy and precision. Moreover, the focal length should be considered for the image quality. This implementation represents the first report of a rotational scanning UBM system. PMID:25254305

Bok, Tae-Hoon; Kim, Juho; Bae, Jinho; Lee, Chong Hyun; Paeng, Dong-Guk

2014-01-01

117

Real-Time Monitoring Of Regional Tissue Elasticity During FUS Focused Ultrasound Therapy Using Harmonic Motion Imaging  

NASA Astrophysics Data System (ADS)

The feasibility of the Harmonic Motion Imaging (HMI) technique for simultaneous monitoring and generation of focused ultrasound therapy using two separate focused ultrasound transducer elements has previously been shown. In this study, a new HMI technique is described that images tissue displacement induced by a harmonic radiation force induced using a single focused ultrasound element. First, wave propagation simulation models were used to compare the use of a single Amplitude-Modulated (AM) focused beam versus two overlapping focused beams as previously implemented for HMI. Simulation results indicated that, unlike in the two-beam configuration, the AM beam produced a consistent, stable focus for the applied harmonic radiation force. The AM beam thus offered the unique advantage of sustaining the application of the spatially-invariant radiation force. Experiments were then performed on gelatin gel phantoms and tissue in vitro bovine liver. The radiation force was generated by a 4.68 MHz focused transducer using a low-frequency Amplitude-Modulated (AM) RF-signal. RF data were acquired at 7.5 MHz with a PRF of 6.5 kHz and displacements were estimated using a 1D cross-correlation algorithm on successive RF signals. Furthermore, taking advantage of the real-time capability of our method, the change in the elastic properties was monitored during focused ultrasound (FUS) ablation of tissue in vitro bovine liver. Based on the harmonic displacements, their temperature-dependence, and the calculated acoustic radiation force, the change in the relative, regional stiffness could be monitored during heating and ablation, both using the displacement amplitude and the resulting phase shift change of the displacement relative to the radiation force temporal profile. In conclusion, the feasibility of using an AM radiation force for HMI for simultaneous monitoring and treatment during ultrasound therapy was demonstrated in phantoms and tissues in vitro. Further study of this method will include, ex vivo and in vivo, stiffness and temperature.

Maleke, Caroline; Pernot, Mathieu; Konofagou, Elisa

2006-05-01

118

A comparison of theoretical and experimental ultrasound field distributions in canine muscle tissue in vivo.  

PubMed

Relative ultrasound field distributions were measured using thermal techniques in canine thighs in vivo and in water. The experimental results were compared with distributions obtained from a numerical model based on the one-dimensional integration of the Rayleigh-Sommerfeld diffraction integral. The comparisons showed that the theoretical model is a good approximation to the distributions measured in water, with the agreement decreasing for regions in front of the acoustic focus. The main lobe profiles obtained in the muscle tissue also agreed well with both theoretical results and results measured in water (focussing was not lost). However, these in vivo distributions showed enlargement of the side lobes indicating scattering of the waves. It was also found that the interfaces between muscle groups produced considerable beam distortions as well as increased side lobe levels. Scattering of energy from the main lobe to the side lobes was verified by measurements of the peak intensity and the total acoustic power attenuation coefficients for passage of the beams through the thighs which showed that the former was about 40% higher than the latter. Also, absolute intensity values at the acoustic focus were measured in water using a hydrophone (0.5 mm active diameter) for 11 transducers ranging in frequency from 0.246 to 3.54 MHz. When these absolute values were compared with the model predictions, it was found that the model consistently overestimated the experimental data by a factor of less than 2. That is, the model can also be used to obtain upper bounds for absolute intensity values. Consequences of these results on ultrasound hyperthermia treatments are discussed. PMID:1566529

Moros, E G; Hynynen, K

1992-01-01

119

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

120

A new nonlinear parameter in the developed strain-to-applied strain of the soft tissues and its application in ultrasound elasticity imaging  

PubMed Central

Strain developed under quasi-static deformation has been mostly used in ultrasound elasticity imaging (UEI) to determine the stiffness change of tissues. However, the strain measure in UEI is often less sensitive to a subtle change of stiffness. This is particularly true for Crohn’s disease where we have applied strain imaging to the differentiation of acutely inflamed bowel from chronically fibrotic bowel. In this study, a new nonlinear elastic parameter of the soft tissues is proposed to overcome this limit. The purpose of this study is to evaluate the newly proposed method and demonstrate its feasibility in the UEI. A non-linear characteristic of soft tissues over a relatively large dynamic range of strain was investigated. A simplified tissue model based on a finite element (FE) analysis was integrated with a laboratory developed ultrasound radio frequency (RF) signal synthesis program. Two dimensional speckle tracking was applied to this model to simulate the nonlinear behavior of the strain developed in a target inclusion over the applied average strain to the surrounding tissues. A nonlinear empirical equation was formulated and optimized to best match the developed strain-to-applied strain relation obtained from the FE simulation. The proposed nonlinear equation was applied to in vivo measurements and nonlinear parameters were further empirically optimized. For an animal model, acute and chronic inflammatory bowel disease was induced in Lewis rats with trinitrobenzene sulfonic acid (TNBS)-ethanol treatments. After UEI, histopathology and direct mechanical measurements were performed on the excised tissues. The extracted non-linear parameter from the developed strain-to-applied strain relation differentiated the three different tissue types with 1.96 ± 0.12 for normal, 1.50 ± 0.09 for the acutely inflamed, and 1.03 ± 0.08 for the chronically fibrotic tissue. T-tests determined that the non-linear parameters between normal, acutely inflamed and fibrotic tissue types were statistically significantly different (normal/fibrotic (P = 0.0000185), normal/acutely inflamed (P = 0.0013), and fibrotic/acutely inflamed (P = 0.0029)). This technique may provide a sensitive and robust tool to assess subtle stiffness changes in tissues such as in acutely inflamed bowel wall. (E-mail: kangkim@upmc.edu) PMID:22266232

Xu, Jingping; Tripathy, Sakya.; Rubin, Jonathan. M.; Stidham, Ryan. W.; Johnson, Laura. A.; Higgins, Peter. D.; Kim, Kang.

2011-01-01

121

Experimental research of longitudinal ultrasound absorption in intermediate state of high pure type I superconductor  

E-print Network

The experimental research of the longitudinal ultrasound absorption in an intermediate state of the high pure Ga single crystal at the frequencies of 30 - 130 MHz at the temperatures of 0.4 - 0.5 K, using the impulse method, is completed. The new effects in the absorption of ultrasound in an intermediate state of the high pure type I superconductor are discovered. The giant oscillations in the dependence of the ultrasound absorption on the magnetic field at the magnitudes below the critical magnetic field, H longitudinal ultrasonic wave f and on the orientation of external magnetic field are reported. In the case of the high frequencies ultrasonic signal, the different behaviour of the monotonous part of the dep...

Shepelev, Anatoly G; Filimonov, Genady D

2012-01-01

122

Sound-speed and attenuation imaging of breast tissue using waveform tomography of transmission ultrasound data  

Microsoft Academic Search

Waveform tomography results are presented from 800 kHz ultrasound transmission scans of a breast phantom, and from an in vivo ultrasound breast scan: significant improvements are demonstrated in resolution over time-of-flight reconstructions. Quantitative reconstructions of both sound-speed and inelastic attenuation are recovered. The data were acquired in the Computed Ultrasound Risk Evaluation (CURE) system, comprising a 20 cm diameter solid-state

R. Gerhard Pratt; Lianjie Huang; Neb Duric; Peter Littrup

2007-01-01

123

Classification algorithm of ovarian tissue based on co-registered ultrasound and photoacoustic tomography  

NASA Astrophysics Data System (ADS)

Human ovarian tissue features extracted from photoacoustic spectra data, beam envelopes and co-registered ultrasound and photoacoustic images are used to characterize cancerous vs. normal processes using a support vector machine (SVM) classifier. The centers of suspicious tumor areas are estimated from the Gaussian fitting of the mean Radon transforms of the photoacoustic image along 0 and 90 degrees. Normalized power spectra are calculated using the Fourier transform of the photoacoustic beamformed data across these suspicious areas, where the spectral slope and 0-MHz intercepts are extracted. Image statistics, envelope histogram fitting and maximum output of 6 composite filters of cancerous or normal patterns along with other previously used features are calculated to compose a total of 17 features. These features are extracted from 169 datasets of 19 ex vivo ovaries. Half of the cancerous and normal datasets are randomly chosen to train a SVM classifier with polynomial kernel and the remainder is used for testing. With 50 times data resampling, the SVM classifier, for the training group, gives 100% sensitivity and 100% specificity. For the testing group, it gives 89.68+/- 6.37% sensitivity and 93.16+/- 3.70% specificity. These results are superior to those obtained earlier by our group using features extracted from photoacoustic raw data or image statistics only.

Li, Hai; Kumavor, Patrick D.; Alqasemi, Umar; Zhu, Quing

2014-03-01

124

Towards the feasibility of using ultrasound to determine mechanical properties of tissues in a bioreactor.  

PubMed

Our ultimate goal is to non-destructively evaluate mechanical properties of tissue-engineered (TE) cartilage using ultrasound (US). We used agarose gels as surrogates for TE cartilage. Previously, we showed that mechanical properties measured using conventional methods were related to those measured using US, which suggested a way to non-destructively predict mechanical properties of samples with known volume fractions. In this study, we sought to determine whether the mechanical properties of samples, with unknown volume fractions could be predicted by US. Aggregate moduli were calculated for hydrogels as a function of SOS, based on concentration and density using a poroelastic model. The data were used to train a statistical model, which we then used to predict volume fractions and mechanical properties of unknown samples. Young's and storage moduli were measured mechanically. The statistical model generally predicted the Young's moduli in compression to within <10% of their mechanically measured value. We defined positive linear correlations between the aggregate modulus predicted from US and both the storage and Young's moduli determined from mechanical tests. Mechanical properties of hydrogels with unknown volume fractions can be predicted successfully from US measurements. This method has the potential to predict mechanical properties of TE cartilage non-destructively in a bioreactor. PMID:25092421

Mansour, Joseph M; Gu, Di-Win Marine; Chung, Chen-Yuan; Heebner, Joseph; Althans, Jake; Abdalian, Sarah; Schluchter, Mark D; Liu, Yiying; Welter, Jean F

2014-10-01

125

Investigation of foreign objects in soft-tissue using a PE-CMOS ultrasound system: a preliminary comparative study  

NASA Astrophysics Data System (ADS)

In this study, we have tested the ability of four imaging modalities to investigate foreign objects in soft tissue. We inserted wood, plastic, glass, and aluminum objects into a pork sample to simulate traumatized soft tissue. Each object was inserted into the skin, then passed through the fat tissue layer and penetrated into the muscle layer. We then took images of the pork sample using four different modalities: (1) a C-Scan imaging prototype which consists of an unfocused transducer, a compound acoustic lens, and a 2D ultrasound sensor array based on the piezoelectric sensing complementary metal-oxide semiconductor (PE-CMOS) technology; (2) a portable B-Scan ultrasound system; (3) a conventional X-ray system; (4) and a computed radiography (CR) X-ray system. We found that the aluminum and glass objects were clearly visible in both conventional X-ray and CR X-ray images with good contrast-to-noise ratio (CNR); however, the wood and plastic objects could not be clearly seen using these modalities. However, we found that the wood, plastic, and glass objects, as well as the thicker aluminum object, were clearly visible in the C-Scan ultrasound images. Furthermore, the fold fibro structures of the fat and muscle tissues in the pork were observable using this modality. The C-Scan prototype images produce neither speckle nor geometry distortion. Both of these issues are commonly seen in B-Scan ultrasound. The results of this study also indicate that the C-Scan images have better CNRs for most foreign objects when compared to other imaging modalities.

Liu, Chu-Chuan; Lo, Shih-Chung Ben; Freedman, Matthew T.; Lasser, Marvin E.; Lasser, Bob; Kula, John; Wang, Yue Joseph; Hsieh, Tsung-I.; Sarcone, Anita

2006-03-01

126

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

Microsoft Academic Search

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,

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

2012-01-01

127

Contrast Enhanced Diagnostic Ultrasound Causes Renal Tissue Damage in a Porcine Model  

PubMed Central

Objective Glomerular capillary hemorrhage (GCH) has been reported and confirmed as a consequence of contrast-enhanced diagnostic ultrasound (CEDUS) of rat kidney. This study assessed renal tissue injury in the larger porcine model. Methods The right kidneys of anesthetized pigs were imaged in 8 groups of 4 pigs. A Vingmed System Five (General Electric Co. Cincinnati OH) was used at 1.5 MHz in B-mode to intermittently scan the kidney at 4 s intervals. A Sequoia 512 (Acuson, Mountain View CA) was used in the 1.5 MHz Cadence CPS mode with intermittent agent-clearance bursts at 4 s intervals. Kidneys were scanned transabdominally, or after laparotomy through a saline standoff. The Sequoia 512 probe was placed in contact with the kidney for one group. Definity (Lantheus Medical Imaging, N. Billerica, MA) was infused at 4 ?l/kg/min (diluted 33:1 in saline) for 4 min during scanning. Results Blood-filled urinary tubules were evident on the kidney surface for all groups, except for the group with the probe in contact with the kidney. GCH was found by histology in 31.7 % ± 9.8 % of glomeruli in the center of the scan plane for 1.7 MPa transabdominal scanning and 1.5 % ± 2.9 % of glomeruli in sham samples (P<0.05). In addition, hematuria was detected after scanning, and tubular obstruction occurred in some nephrons. Conclusion Renal tissue damage was induced by CEDUS in the porcine model. This result, together with previous studies in rats, support an hypothesis that GCH would occur in humans from similar CEDUS. PMID:20876892

Miller, Douglas L.; Dou, Chunyan; Wiggins, Roger C.

2010-01-01

128

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

PubMed Central

A new system is presented for generating controlled tissue heating with a clinical ultrasound scanner, and initial in vitro and in vivo results are presented that demonstrate both transient and sustained heating in the mild-hyperthermia range of 37–42ºC. The system consists of a Siemens Antares™ ultrasound scanner, a custom dual-frequency 3-row transducer array and an external temperature feedback control system. The transducer has 2 outer rows that operate at 1.5 MHz for tissue heating and a center row that operates at 5 MHz for B-mode imaging to guide the therapy. We compare the field maps obtained using a hydrophone against calculations of the ultrasound beam based on monochromatic and linear assumptions. Using the finite-difference time-domain (FDTD) method, we compare predicted time-dependent thermal profiles to measured profiles for soy tofu as a tissue-mimicking phantom. In vitro results show differential heating of 6ºC for chicken breast and tofu. In vivo tests of the system were performed on three mice bearing Met-1 tumors, which is a model of aggressive, metastatic and highly vascular breast cancer. In superficially implanted tumors, we demonstrate controlled heating to 42ºC. We show that the system is able to maintain the temperature to within 0.1ºC of the desired temperature both in vitro and in vivo. PMID:20064754

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

2009-01-01

129

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. PMID:22736690

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

2012-01-01

130

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

131

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 3.7 mm 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 5 minutes 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

2013-10-01

132

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%. PMID:22927890

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

2012-01-01

133

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. PMID:21937339

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

2012-01-01

134

Data Analysis and Tissue Type Assignment for Glioblastoma Multiforme  

PubMed Central

Glioblastoma multiforme (GBM) is characterized by high infiltration. The interpretation of MRSI data, especially for GBMs, is still challenging. Unsupervised methods based on NMF by Li et al. (2013, NMR in Biomedicine) and Li et al. (2013, IEEE Transactions on Biomedical Engineering) have been proposed for glioma recognition, but the tissue types is still not well interpreted. As an extension of the previous work, a tissue type assignment method is proposed for GBMs based on the analysis of MRSI data and tissue distribution information. The tissue type assignment method uses the values from the distribution maps of all three tissue types to interpret all the information in one new map and color encodes each voxel to indicate the tissue type. Experiments carried out on in vivo MRSI data show the feasibility of the proposed method. This method provides an efficient way for GBM tissue type assignment and helps to display information of MRSI data in a way that is easy to interpret. PMID:24724098

Li, Yuqian; Pi, Yiming; Liu, Xin; Liu, Yuhan; Van Cauter, Sofie

2014-01-01

135

Integrated photoacoustic, ultrasound and fluorescence platform for diagnostic medical imaging-proof of concept study with a tissue mimicking phantom  

PubMed Central

The structural and molecular heterogeneities of biological tissues demand the interrogation of the samples with multiple energy sources and provide visualization capabilities at varying spatial resolution and depth scales for obtaining complementary diagnostic information. A novel multi-modal imaging approach that uses optical and acoustic energies to perform photoacoustic, ultrasound and fluorescence imaging at multiple resolution scales from the tissue surface and depth is proposed in this paper. The system comprises of two distinct forms of hardware level integration so as to have an integrated imaging system under a single instrumentation set-up. The experimental studies show that the system is capable of mapping high resolution fluorescence signatures from the surface, optical absorption and acoustic heterogeneities along the depth (>2cm) of the tissue at multi-scale resolution (<1µm to <0.5mm). PMID:25071954

James, Joseph; Murukeshan, Vadakke Matham; Woh, Lye Sun

2014-01-01

136

Microbubble type and distribution dependence of focused ultrasound-induced blood-brain barrier opening.  

PubMed

Focused ultrasound, in the presence of microbubbles, has been used non-invasively to induce reversible blood-brain barrier (BBB) opening in both rodents and non-human primates. This study was aimed at identifying the dependence of BBB opening properties on polydisperse microbubble (all clinically approved microbubbles are polydisperse) type and distribution by using a clinically approved ultrasound contrast agent (Definity microbubbles) and in-house prepared polydisperse (IHP) microbubbles in mice. A total of 18 C57 BL/6 mice (n = 3) were used in this study, and each mouse was injected with either Definity or IHP microbubbles via the tail vein. The concentration and size distribution of activated Definity and IHP microbubbles were measured, and the microbubbles were diluted to 6 × 10(8)/mL before injection. Immediately after microbubble administration, mice were subjected to focused ultrasound with the following parameters: frequency = 1.5 MHz, pulse repetition frequency = 10 Hz, 1000 cycles, in situ peak rarefactional acoustic pressures = 0.3, 0.45 and 0.6 MPa for a sonication duration of 60 s. Contrast-enhanced magnetic resonance imaging was used to confirm BBB opening and allowed for image-based analysis. Permeability of the treated region and volume of BBB opening did not significantly differ between the two types of microbubbles (p > 0.05) at peak rarefractional acoustic pressures of 0.45 and 0.6 MPa, whereas IHP microbubbles had significantly higher permeability and opening volume (p < 0.05) at the relatively lower pressure of 0.3 MPa. The results from this study indicate that microbubble type and distribution could have significant effects on focused ultrasound-induced BBB opening at lower pressures, but less important effects at higher pressures, possibly because of the stable cavitation that governs the former. This difference may have become less significant at higher pressures, where inertial cavitation typically occurs. PMID:24239362

Wang, Shutao; Samiotaki, Gesthimani; Olumolade, Oluyemi; Feshitan, Jameel A; Konofagou, Elisa E

2014-01-01

137

Development of a Tissue-Mimicking Phantom for Evaluating the Focusing Performance of High Intensity Focused Ultrasound  

SciTech Connect

Objectives: To develop a tissue mimicking phantom which can be used to evaluate the focusing performance of the HIFU transducer, and the phantom should has the same acoustic characteristic and thermotics characteristic as the biological tissue. Materials and methods: The tissue mimicking phantom was made from water, gelatin, fresh biologic tissue Its ultrasonic parameters (attenuation coefficient) of the phantom was measured by the method of radiation pressure, and thermotics parameters of the phantom, including thermal conductivity, specific heat/fusion point et al were tested under the Measurement meter. The HIFU biological effect of the phantom was evaluated under the Model JC focused ultrasound tumor therapeutic system, developed and produced by Chongqing HIFU Technology Co. Ltd (working frequency: 0.7MHz; acoustic power: 200W; focal distance: 135mm; Acoustic focal region: 3x3x25 cubic mm). Results: The self-made phantom is sable, has smooth and glossy appearance, well-distributed construction, and good elasticity. We measured the followed values for acoustic and thermal properties: density 1049{+-}2 kg/m3; attenuation 0.532{+-}0.017 dB/cm (0.8 MHz), 0.612{+-}0.021 dB/cm (1.0 MHz); thermal conductivity 0.76{+-}0.08 W/m/- deg. C; specific heat 3653{+-}143 J/kg- deg. C; fusion point154{+-}8 deg. C. The BFR induced in the phantom after HIFU exposure was stable in its size and appearance. Conclusion: We produced and improved one tissue mimicking phantom successfully which had semblable ultrasound and thermphysical properties like the soft tissue, and can replace the bovine liver to investigate the HIFU biological effect and to detect the focusing performance of the HIFU energy transducer. The research was supported by Chongqing University of Medical Science (CX200320)

Jing Zongyu; Li Faqi; Zou Jiangzhong; Wang Zhibiao [Institute of Ultrasound Engineering in Medicine, Biomedical Engineering Dept., Chongqing University of Medical Sciences, Chongqing 400016 (China)

2006-05-08

138

Detecting tissue optical and mechanical properties with an ultrasound modulated optical imaging system in reflection detection geometry  

PubMed Central

Tissue optical and mechanical properties are correlated to tissue pathologic changes. This manuscript describes a dual-mode ultrasound modulated optical imaging system capable of sensing local optical and mechanical properties in reflection geometry. The optical characterisation was achieved by the acoustic radiation force assisted ultrasound modulated optical tomography (ARF-UOT) with laser speckle contrast detection. Shear waves generated by the ARF were also tracked optically by the same system and the shear wave speed was used for the elasticity measurement. Tissue mimicking phantoms with multiple inclusions buried at 11 mm depth were experimentally scanned with the dual-mode system. The inclusions, with higher optical absorption and/or higher stiffness than background, were identified based on the dual results and their stiffnesses were quantified. The system characterises both optical and mechanical properties of the inclusions compared with the ARF-UOT or the elasticity measurement alone. Moreover, by detecting the backward scattered light in reflection detection geometry, the system is more suitable for clinical applications compared with transmission geometry.

Cheng, Yi; Li, Sinan; Eckersley, Robert J.; Elson, Daniel S.; Tang, Meng-Xing

2014-01-01

139

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

140

Real-Time Assessment of Tissue Hypoxia In Vivo with Combined Photoacoustics and High-Frequency Ultrasound  

PubMed Central

Purpose: In preclinical cancer studies, non-invasive functional imaging has become an important tool to assess tumor development and therapeutic effects. Tumor hypoxia is closely associated with tumor aggressiveness and is therefore a key parameter to be monitored. Recently, photoacoustic (PA) imaging with inherently co-registered high-frequency ultrasound (US) has reached preclinical applicability, allowing parallel collection of anatomical and functional information. Dual-wavelength PA imaging can be used to quantify tissue oxygen saturation based on the absorbance spectrum differences between hemoglobin and deoxyhemoglobin. Experimental Design: A new bi-modal PA/US system for small animal imaging was employed to test feasibility and reliability of dual-wavelength PA for measuring relative tissue oxygenation. Murine models of pancreatic and colon cancer were imaged, and differences in tissue oxygenation were compared to immunohistochemistry for hypoxia in the corresponding tissue regions. Results: Functional studies proved feasibility and reliability of oxygenation detection in murine tissue in vivo. Tumor models exhibited different levels of hypoxia in localized regions, which positively correlated with immunohistochemical staining for hypoxia. Contrast-enhanced imaging yielded complementary information on tissue perfusion using the same system. Conclusion: Bimodal PA/US imaging can be utilized to reliably detect hypoxic tumor regions in murine tumor models, thus providing the possibility to collect anatomical and functional information on tumor growth and treatment response live in longitudinal preclinical studies. PMID:24723982

Gerling, Marco; Zhao, Ying; Nania, Salvatore; Norberg, K. Jessica; Verbeke, Caroline S.; Englert, Benjamin; Kuiper, Raoul V.; Bergström, Åsa; Hassan, Moustapha; Neesse, Albrecht; Löhr, J. Matthias; Heuchel, Rainer L.

2014-01-01

141

Photoacoustic detection and optical spectroscopy of high-intensity focused ultrasound-induced thermal lesions in biologic tissue  

SciTech Connect

Purpose: The aims of this study are: (a) to investigate the capability of photoacoustic (PA) method in detecting high-intensity focused ultrasound (HIFU) treatments in muscle tissuesin vitro; and (b) to determine the optical properties of HIFU-treated and native tissues in order to assist in the interpretation of the observed contrast in PA detection of HIFU treatments. Methods: A single-element, spherically concaved HIFU transducer with a centre frequency of 1 MHz was utilized to create thermal lesions in chicken breast tissuesin vitro. To investigate the detectability of HIFU treatments photoacoustically, PA detection was performed at 720 and 845 nm on seven HIFU-treated tissue samples. Within each tissue sample, PA signals were acquired from 22 locations equally divided between two regions of interest within two volumes in tissue – a HIFU-treated volume and an untreated volume. Optical spectroscopy was then carried out on 10 HIFU-treated chicken breast specimens in the wavelength range of 500–900 nm, in 1-nm increments, using a spectrophotometer with an integrating sphere attachment. The authors’ optical spectroscopy raw data (total transmittance and diffuse reflectance) were used to obtain the optical absorption and reduced scattering coefficients of HIFU-induced thermal lesions and native tissues by employing the inverse adding-doubling method. The aforementioned interaction coefficients were subsequently used to calculate the effective attenuation coefficient and light penetration depth of HIFU-treated and native tissues in the wavelength range of 500–900 nm. Results: HIFU-treated tissues produced greater PA signals than native tissues at 720 and 845 nm. At 720 nm, the averaged ratio of the peak-to-peak PA signal amplitude of HIFU-treated tissue to that of native tissue was 3.68 ± 0.25 (mean ± standard error of the mean). At 845 nm, the averaged ratio of the peak-to-peak PA signal amplitude of HIFU-treated tissue to that of native tissue was 3.75 ± 0.26 (mean ± standard error of the mean). The authors’ spectroscopic investigation has shown that HIFU-treated tissues have a greater optical absorption and reduced scattering coefficients than native tissues in the wavelength range of 500–900 nm. In fact, at 720 and 845 nm, the ratio of the optical absorption coefficient of HIFU-treated tissues to that of native tissues was 1.13 and 1.17, respectively; on the other hand, the ratio of the reduced scattering coefficient of HIFU-treated tissues to that of native tissues was 13.22 and 14.67 at 720 and 845 nm, respectively. Consequently, HIFU-treated tissues have a higher effective attenuation coefficient and a lower light penetration depth than native tissues in the wavelength range 500–900 nm. Conclusions: Using a PA approach, HIFU-treated tissues interrogated at 720 and 845 nm optical wavelengths can be differentiated from untreated tissues. Based on the authors’ spectroscopic investigation, the authors conclude that the observed PA contrast between HIFU-induced thermal lesions and untreated tissue is due, in part, to the increase in the optical absorption coefficient, the reduced scattering coefficient and, therefore, the deposited laser energy fluence in HIFU-treated tissues.

Alhamami, Mosa; Kolios, Michael C.; Tavakkoli, Jahan, E-mail: jtavakkoli@ryerson.ca [Department of Physics, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3 (Canada)] [Department of Physics, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3 (Canada)

2014-05-15

142

Noninvasive Quantification of In Vitro Osteoblastic Differentiation in 3D Engineered Tissue Constructs Using Spectral Ultrasound Imaging  

PubMed Central

Non-destructive monitoring of engineered tissues is needed for translation of these products from the lab to the clinic. In this study, non-invasive, high resolution spectral ultrasound imaging (SUSI) was used to monitor the differentiation of MC3T3 pre-osteoblasts seeded within collagen hydrogels. SUSI was used to measure the diameter, concentration and acoustic attenuation of scatterers within such constructs cultured in either control or osteogenic medium over 21 days. Conventional biochemical assays were used on parallel samples to determine DNA content and calcium deposition. Construct volume and morphology were accurately imaged using ultrasound. Cell diameter was estimated to be approximately 12.5–15.5 µm using SUSI, which corresponded well to measurements of fluorescently stained cells. The total number of cells per construct assessed by quantitation of DNA content decreased from 5.6±2.4×104 at day 1 to 0.9±0.2×104 at day 21. SUSI estimation of the equivalent number of acoustic scatters showed a similar decreasing trend, except at day 21 in the osteogenic samples, which showed a marked increase in both scatterer number and acoustic impedance, suggestive of mineral deposition by the differentiating MC3T3 cells. Estimation of calcium content by SUSI was 41.7±11.4 µg/ml, which agreed well with the biochemical measurement of 38.7±16.7 µg/ml. Color coded maps of parameter values were overlaid on B-mode images to show spatiotemporal changes in cell diameter and calcium deposition. This study demonstrates the use of non-destructive ultrasound imaging to provide quantitative information on the number and differentiated state of cells embedded within 3D engineered constructs, and therefore presents a valuable tool for longitudinal monitoring of engineered tissue development. PMID:24465680

Peterson, Alexis W.; Caldwell, David J.; Stegemann, Jan P.; Deng, Cheri X.

2014-01-01

143

Comparison of finite element and heated disc models of tissue heating by ultrasound  

Microsoft Academic Search

This paper compares different techniques used to model the heating caused by ultrasound (US) in a phantom containing a layer of bone mimic covered by agar gel. Results from finite element (FE) models are compared with those from two techniques based on the point-source solution to the bioheat transfer equation (BHTE): one in which the bone mimic is considered to

Claire Doody; Francis A. Duck; Victor F. Humphrey

2000-01-01

144

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

2012-02-21

145

Stereotypic Laryngeal and Respiratory Motor Patterns Generate Different Call Types in Rat Ultrasound Vocalization  

PubMed Central

Rodents produce highly variable ultrasound whistles as communication signals unlike many other mammals, who employ flow-induced vocal fold oscillations to produce sound. The role of larynx muscles in controlling sound features across different call types in ultrasound vocalization (USV) was investigated using laryngeal muscle electromyographic (EMG) activity, subglottal pressure measurements and vocal sound output in awake and spontaneously behaving Sprague–Dawley rats. Results support the hypothesis that glottal shape determines fundamental frequency. EMG activities of thyroarytenoid and cricothyroid muscles were aligned with call duration. EMG intensity increased with fundamental frequency. Phasic activities of both muscles were aligned with fast changing fundamental frequency contours, for example in trills. Activities of the sternothyroid and sternohyoid muscles, two muscles involved in vocal production in other mammals, are not critical for the production of rat USV. To test how stereotypic laryngeal and respiratory activity are across call types and individuals, sets of ten EMG and subglottal pressure parameters were measured in six different call types from six rats. Using discriminant function analysis, on average 80% of parameter sets were correctly assigned to their respective call type. This was significantly higher than the chance level. Since fundamental frequency features of USV are tightly associated with stereotypic activity of intrinsic laryngeal muscles and muscles contributing to build-up of subglottal pressure, USV provide insight into the neurophysiological control of peripheral vocal motor patterns. PMID:23423862

RIEDE, TOBIAS

2014-01-01

146

Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid  

MedlinePLUS

... are similar to sonar used by boats and submarines. The ultrasound image is immediately visible on a ... patient), as well as the type of body structure and composition of body tissue through which the ...

147

SOUND-SPEED AND ATTENUATION IMAGING OF BREAST TISSUE USING WAVEFORM TOMOGRAPHY OF TRANSMISSION ULTRASOUND DATA  

SciTech Connect

Waveform tomography results are presented from 800 kHz ultrasound transmission scans of a breast phantom, and from an in vivo ultrasound breast scan: significant improvements are demonstrated in resolution over time-of-flight reconstructions. Quantitative reconstructions of both sound-speed and inelastic attenuation are recovered. The data were acquired in the Computed Ultrasound Risk Evaluation (CURE) system, comprising a 20 cm diameter solid-state ultrasound ring array with 256 active, non-beamforming transducers. Waveform tomography is capable of resolving variations in acoustic properties at sub-wavelength scales. This was verified through comparison of the breast phantom reconstructions with x-ray CT results: the final images resolve variations in sound speed with a spatial resolution close to 2 mm. Waveform tomography overcomes the resolution limit of time-of-flight methods caused by finite frequency (diffraction) effects. The method is a combination of time-of-flight tomography, and 2-D acoustic waveform inversion of the transmission arrivals in ultrasonic data. For selected frequency components of the waveforms, a finite-difference simulation of the visco-acoustic wave equation is used to compute synthetic data in the current model, and the data residuals are formed by subtraction. The residuals are used in an iterative, gradient-based scheme to update the sound-speed and attenuation model to produce a reduced misfit to the data. Computational efficiency is achieved through the use of time-reversal of the data residuals to construct the model updates. Lower frequencies are used first, to establish the long wavelength components of the image, and higher frequencies are introduced later to provide increased resolution.

HUANG, LIANJIE [Los Alamos National Laboratory; PRATT, R. GERHARD [Los Alamos National Laboratory; DURIC, NEB [Los Alamos National Laboratory; LITTRUP, PETER [Los Alamos National Laboratory

2007-01-25

148

Sound-speed and attenuation imaging of breast tissue using waveform tomography of transmission ultrasound data  

NASA Astrophysics Data System (ADS)

Waveform tomography results are presented from 800 kHz ultrasound transmission scans of a breast phantom, and from an in vivo ultrasound breast scan: significant improvements are demonstrated in resolution over time-of-flight reconstructions. Quantitative reconstructions of both sound-speed and inelastic attenuation are recovered. The data were acquired in the Computed Ultrasound Risk Evaluation (CURE) system, comprising a 20 cm diameter solid-state ultrasound ring array with 256 active, non-beamforming transducers. Waveform tomography is capable of resolving variations in acoustic properties at sub-wavelength scales. This was verified through comparison of the breast phantom reconstructions with x-ray CT results: the final images resolve variations in sound speed with a spatial resolution close to 2 mm. Waveform tomography overcomes the resolution limit of time-of-flight methods caused by finite frequency (diffraction) effects. The method is a combination of time-of-flight tomography, and 2-D acoustic waveform inversion of the transmission arrivals in ultrasonic data. For selected frequency components of the waveforms, a finite-difference simulation of the visco-acoustic wave equation is used to compute synthetic data in the current model, and the data residuals are formed by subtraction. The residuals are used in an iterative, gradient-based scheme to update the sound-speed and attenuation model to produce a reduced misfit to the data. Computational efficiency is achieved through the use of time-reversal of the data residuals to construct the model updates. Lower frequencies are used first, to establish the long wavelength components of the image, and higher frequencies are introduced later to provide increased resolution.

Pratt, R. Gerhard; Huang, Lianjie; Duric, Neb; Littrup, Peter

2007-03-01

149

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. PMID:20018433

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

2009-01-01

150

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

PubMed

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 been investigated previously and found to not 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/cm(2) 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 with calculations using weak shock theory and the shock amplitudes obtained from nonlinear modeling and 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 as a result of shock waves is therefore important to HIFU, and clinicians should be aware of the potential for very rapid boiling because it alters treatments. PMID:20018433

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

2010-02-01

151

Needle Steering in Biological Tissue using Ultrasound-based Online Curvature Estimation  

E-print Network

in a homogenous gelatin phantom, a two-layer gelatin phantom, and a biological tissue phantom composed of a gelatin layer and in vitro chicken tissue. In all experiments, virtual obstacles and targets move in order phantom composed of gelatin and biological tissue. Steerable needles have been introduced to enable

North Carolina at Chapel Hill, University of

152

Method of and Apparatus for Histological Human Tissue Characterization Using Ultrasound  

NASA Technical Reports Server (NTRS)

A method and apparatus for determining important histological characteristics of tissue, including a determination of the tissue's health is discussed. Electrical pulses are converted into meaningful numerical representations through the use of Fourier Transforms. These numerical representations are then used to determine important histological characteristics of tissue. This novel invention does not require rectification and thus provides for detailed information from the ultrasonic scan.

Yost, William T. (Inventor); Cantrell, John H. (Inventor); Taler, George A. (Inventor)

1998-01-01

153

Method of and Apparatus for Histological Human Tissue Characterization Using Ultrasound  

NASA Technical Reports Server (NTRS)

A method and apparatus for determining important histological characteristics of tissue, including a determination of the tissue's health. Electrical pulses are converted into meaningful numerical representations through the use of Fourier Transforms. These numerical representations are then used to determine important histological characteristics of tissue. This novel invention does not require rectification and thus provides for detailed information from the ultrasonic scan.

Yost, William T. (Inventor); Cantrell, John H. (Inventor); TalEr, George A. (Inventor)

1999-01-01

154

Electromagnetically tracked ultrasound for small animal imaging  

Microsoft Academic Search

The fusion of computed tomography (CT) and ultrasound (US) imaging has recently been examined for guiding interventional procedures such as biopsy, local drug delivery and radiofrequency ablation. During combined CT\\/US procedures, US facilitates real time visualization of blood flow and tissue structure, while CT provides a three-dimensional view of an extended region and is capable of differentiating tissue types based

Charles F. Caskey; Mario Hlawitschka; Shengping Qin; Katherine W. Ferrara

2010-01-01

155

HOX D13 expression across 79 tumor tissue types.  

PubMed

HOX genes control normal development, primary cellular processes and are characterized by a unique genomic network organization. Locus D HOX genes play an important role in limb generation and mesenchymal condensation. Dysregulated HOXD13 expression has been detected in breast cancer, melanoma, cervical cancer and astrocytomas. We have investigated the epidemiology of HOXD13 expression in human tissues and its potential deregulation in the carcinogenesis of specific tumors. HOXD13 homeoprotein expression has been detected using microarray technology comprising more than 4,000 normal and neoplastic tissue samples including 79 different tumor categories. Validation of HOXD13 expression has been performed, at mRNA level, for selected tumor types. Significant differences are detectable between specific normal tissues and corresponding tumor types with the majority of cancers showing an increase in HOXD13 expression (16.1% normal vs. 57.7% cancers). In contrast, pancreas and stomach tumor subtypes display the opposite trend. Interestingly, detection of the HOXD13 homeoprotein in pancreas-tissue microarrays shows that its negative expression has a significant and adverse effect on the prognosis of patients with pancreatic cancer independent of the T or N stage at the time of diagnosis. Our study provides, for the first time, an overview of a HOX protein expression in a large series of normal and neoplastic tissue types, identifies pancreatic cancer as one of the most affected by the HOXD13 hoemoprotein and underlines the way homeoproteins can be associated to human cancerogenesis. PMID:19488988

Cantile, Monica; Franco, Renato; Tschan, Adrienne; Baumhoer, Daniel; Zlobec, Inti; Schiavo, Giulia; Forte, Iris; Bihl, Michel; Liguori, Giuseppina; Botti, Gerardo; Tornillo, Luigi; Karamitopoulou-Diamantis, Eva; Terracciano, Luigi; Cillo, Clemente

2009-10-01

156

An innovative ultrasound foot scanner system for measuring the change in biomechanical properties of plantar tissue from sitting to standing.  

PubMed

The present study investigated the reliability of an innovative ultrasound foot scanner system in assessing the thickness and stiffness of plantar soft tissue and the comparison of stiffness and thickness in sitting and standing. Fifteen young healthy individuals were examined. The target sites on the foot sole for investigation included the heel pad, the fifth metatarsal head, the second metatarsal head, the first metatarsal head, and the pulp of the hallux. The test (day 1) and retest (day 2) were performed 1 week apart at the exact time with humidity and temperature of the assessment room under control. The thickness and stiffness of the plantar soft tissue obtained in sitting and standing positions on day 1 were used for comparison. The results showed significant test-retest reliability [intraclass correlation coefficient(3,2)>0.90, P<0.001] at all five sites in both sitting and standing positions. When changing from sitting to standing, the plantar soft tissue became significantly thinner (with decrease ranging from 10 to 14% at various sites) and stiffer (with increase ranging from 123 to 164% at various sites, all P<0.05). The present innovative system is a reliable device for the measurement of the thickness and stiffness of plantar soft tissue in either the sitting or the standing position. The change in positions from sitting to standing resulted in a significant thinning and stiffening of plantar soft tissues. This system could be a potential clinical device to monitor the biomechanical properties of plantar tissue in the elderly or in patients with diseases such as diabetes to estimate the risk of developing foot ulcer or other foot complications. PMID:25426574

Ng, Thomas Ka-Wai; Zheng, Yong-Ping; Kwan, Rachel Lai-Chu; Cheing, Gladys Lai-Ying

2014-11-25

157

Combined Ultrasound and Photoacoustic Imaging to Noninvasively Assess Burn Injury and Selectively Monitor a Regenerative Tissue-Engineered Construct.  

PubMed

Current biomedical imaging tools have limitations in accurate assessment of the severity of open and deep burn wounds involving excess bleeding and severe tissue damage. Furthermore, sophisticated imaging techniques are needed for advanced therapeutic approaches such as noninvasive monitoring of stem cells seeded and applied in a biomedical 3D scaffold to enhance wound repair. The present work introduces a novel application of combined ultrasound (US) and photoacoustic (PA) imaging to assess both burn injury and skin tissue regeneration. Tissue structural damage and bleeding throughout the epidermis and dermis up to the subcutaneous skin layer were imaged noninvasively by US/PA imaging. Gold nanoparticle-labeled adipose-derived stem cells (ASCs) within a PEGylated fibrin 3D gel were implanted in a rodent model of cutaneous burn injury. ASCs were successfully tracked up to two weeks and were distinguished from host tissue components (e.g. epidermis, fat, and blood vessels) through spectroscopic PA imaging. The structure and function of blood vessels (vessel density and perfusion) in the wound bed undergoing skin tissue regeneration were monitored qualitatively and semi-quantitatively by the developed imaging approach. Imaging-based analysis demonstrated ASC localization in the top layer of skin and a higher density of regenerating blood vessels in the treated groups. This was corroborated with histological analysis showing localization of fluorescently-labeled ASCs and smooth muscle alpha actin-positive blood vessels. Overall, the US/PA imaging-based strategy coupled with gold nanoparticles has a great potential for stem cell therapies and tissue engineering due to its noninvasiveness, safety, selectivity, and ability to provide long-term monitoring. PMID:25384558

Nam, Seung Yun; Chung, Eunna; Suggs, Laura J; Emelianov, Stanislav Y

2014-11-10

158

Ultrasonic tissue-type imaging (TTI) for planning treatment of prostate cancer  

NASA Astrophysics Data System (ADS)

Our research is intended to develop ultrasonic methods for characterizing cancerous prostate tissue and thereby to improve the effectiveness of biopsy guidance, therapy targeting, and treatment monitoring. We acquired radio-frequency (RF) echo-signal data and clinical variables, e.g., PSA, during biopsy examinations. We computed spectra of the RF signals in each biopsied region, and trained neural network classifers with over 3,000 sets of data using biopsy data as the gold standard. For imaging, a lookup table returned scores for cancer likelihood on a pixel-by-pixel basis from spectral-parameter and PSA values. Using ROC analyses, we compared classification performance of artificial neural networks (ANNs) to conventional classification with a leave-one-patient-out approach intended to minimize the chance of bias. Tissue-type images (TTIs) were compared to prostatectomy histology to further assess classification performance. ROC-curve areas were greater for ANNs than for the B-mode-based classification by more than 20%, e.g., 0.75 +/- 0.03 for neural-networks vs. 0.64 +/- 0.03 for B-mode LOSs. ANN sensitivity was 17% better than the sensitivity range of ultrasound-guided biopsies. TTIs showed tumors that were entirely unrecognized in conventional images and undetected during surgery. We are investigating TTIs for guiding prostrate biopsies, and for planning radiation dose-escalation and tissue-sparing options, and monitoring prostrate cancer.

Feleppa, Ernest J.; Ketterling, Jeffrey A.; Porter, Christopher R.; Gillespie, John; Wuu, Cheng-Shie; Urban, Stella; Kalisz, Andrew; Ennis, Ronald D.; Schiff, Peter B.

2004-04-01

159

Two types of brown adipose tissue in humans  

PubMed Central

During the last years the existence of metabolically active brown adipose tissue in adult humans has been widely accepted by the research community. Its unique ability to dissipate chemical energy stored in triglycerides as heat makes it an attractive target for new drugs against obesity and its related diseases. Hence the tissue is now subject to intense research, the hypothesis being that an expansion and/or activation of the tissue is associated with a healthy metabolic phenotype. Animal studies provide evidence for the existence of at least two types of brown adipocytes. Apart from the classical brown adipocyte that is found primarily in the interscapular region where it constitutes a thermogenic organ, a second type of brown adipocyte, the so-called beige adipocyte, can appear within white adipose tissue depots. The fact that the two cell types develop from different precursors suggests that they might be recruited and stimulated by different cues and therefore represent two distinct targets for therapeutic intervention. The aim of this commentary is to discuss recent work addressing the question whether also humans possess two types of brown adipocytes and to highlight some issues when looking for molecular markers for such cells. PMID:24575372

Lidell, Martin E; Betz, Matthias J; Enerbäck, Sven

2014-01-01

160

Cytoglobin: A Novel Globin Type Ubiquitously Expressed in Vertebrate Tissues  

Microsoft Academic Search

Vertebrates possess multiple respiratory globins that differ in terms of structure, function, and tissue distribution. Three types of globins have been described so far: hemoglobin facilitates the transport of oxygen in the blood, myoglobin serves oxygen transport and storage in the muscle, and neuroglobin has a yet unidentified function in nerve cells. Here we report the identification of a fourth

Thorsten Burmester; Bettina Ebner; Bettina Weich; Thomas Hankeln

161

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. PMID:23573167

Girault, Jean-Marc

2013-01-01

162

Effect of substrate choice and tissue type on tissue preparation for spectral histopathology by Raman microspectroscopy.  

PubMed

Raman spectroscopy is a non-destructive, non-invasive, rapid and economical technique which has the potential to be an excellent method for the diagnosis of cancer and understanding disease progression through retrospective studies of archived tissue samples. Historically, biobanks are generally comprised of formalin fixed paraffin preserved tissue and as a result these specimens are often used in spectroscopic research. Tissue in this state has to be dewaxed prior to Raman analysis to reduce paraffin contributions in the spectra. However, although the procedures are derived from histopathological clinical practice, the efficacy of the dewaxing procedures that are currently employed is questionable. Ineffective removal of paraffin results in corruption of the spectra and previous experiments have shown that the efficacy can depend on the dewaxing medium and processing time. The aim of this study was to investigate the influence of commonly used spectroscopic substrates (CaF2, Spectrosil quartz and low-E slides) and the influence of different histological tissue types (normal, cancerous and metastatic) on tissue preparation and to assess their use for spectral histopathology. Results show that CaF2 followed by Spectrosil contribute the least to the spectral background. However, both substrates retain paraffin after dewaxing. Low-E substrates, which exhibit the most intense spectral background, do not retain wax and resulting spectra are not affected by paraffin peaks. We also show a disparity in paraffin retention depending upon the histological identity of the tissue with abnormal tissue retaining more paraffin than normal. PMID:24308030

Fullwood, Leanne M; Griffiths, Dave; Ashton, Katherine; Dawson, Timothy; Lea, Robert W; Davis, Charles; Bonnier, Franck; Byrne, Hugh J; Baker, Matthew J

2014-01-21

163

Analysis of Temperature Rise Induced by High-Intensity Focused Ultrasound in Tissue-Mimicking Gel Considering Cavitation Bubbles  

NASA Astrophysics Data System (ADS)

High-intensity focused ultrasound (HIFU) causes a selective temperature rise in tissue and is used as a noninvasive method for tumor treatment. However, there is a problem in that it typically takes several hours to treat a large tumor. The development of a highly efficient method is required to shorten the treatment time. It is known that cavitation bubbles generated by HIFU enhance HIFU heating. In this study, the enhancement of the heating effect by cavitation was estimated in a numerical simulation solving a bio-heat transfer equation (BHTE) by increasing the absorption coefficients in and out of the volume of cavitation bubbles. The absorption coefficients were obtained by a curve fitting the temperature rise near the focal point between experiment and simulation. The results show that cavitation bubbles caused the increase in ultrasonic absorption not only in but also near the volume of cavitation bubbles.

Asai, Ayumu; Okano, Hiroki; Yoshizawa, Shin; Umemura, Shin-ichiro

2013-07-01

164

Backward-mode multiwavelength photoacoustic scanner using a planar Fabry-Perot polymer film ultrasound sensor for high-resolution three-dimensional imaging of biological tissues  

Microsoft Academic Search

A multiwavelength backward-mode planar photoacoustic scanner for 3D imaging of soft tissues to depths of several millimeters with a spatial resolution in the tens to hundreds of micrometers range is described. The system comprises a tunable optical parametric oscillator laser system that provides nanosecond laser pulses between 600 and 1200 nm for generating the photoacoustic signals and an optical ultrasound

Edward Zhang; Jan Laufer; Paul Beard

2008-01-01

165

Transrectal Ablation Of Prostate Tissue Using Focused Ultrasound N.T. Sanghvil.2, R.S. Foster3, R. Bihrle3, F.J. Fry', M. Phillips' and  

E-print Network

attempting to improve cost-effectiveness of treatment (which is highly dependent upon the length, ultrasound can also be focused deep within the body to destroy small regions of tissue without causing damage protocol was devised to evaluate the safety and clinical effectiveness in humans. MATERIALS AND METHODS

Illinois at Urbana-Champaign, University of

166

Thermal fixation of swine liver tissue after magnetic resonance-guided high-intensity focused ultrasound ablation.  

PubMed

The aim of this study was to investigate experimental conditions for efficient and controlled in vivo liver tissue ablation by magnetic resonance (MR)-guided high-intensity focused ultrasound (HIFU) in a swine model, with the ultimate goal of improving clinical treatment outcome. Histological changes were examined both acutely (four animals) and 1 wk after treatment (five animals). Effects of acoustic power and multiple sonication cycles were investigated. There was good correlation between target size and observed ablation size by thermal dose calculation, post-procedural MR imaging and histopathology, when temperature at the focal point was kept below 90°C. Structural histopathology investigations revealed tissue thermal fixation in ablated regions. In the presence of cavitation, mechanical tissue destruction occurred, resulting in an ablation larger than the target. Complete extra-corporeal MR-guided HIFU ablation in the liver is feasible using high acoustic power. Nearby large vessels were preserved, which makes MR-guided HIFU promising for the ablation of liver tumors adjacent to large veins. PMID:24768489

Courivaud, Frédéric; Kazaryan, Airazat M; Lund, Alice; Orszagh, Vivian C; Svindland, Aud; Marangos, Irina Pavlik; Halvorsen, Per Steinar; Jebsen, Peter; Fosse, Erik; Hol, Per Kristian; Edwin, Bjørn

2014-07-01

167

Comparison of pulsed photothermal radiometry, optical coherence tomography and ultrasound for melanoma thickness measurement in PDMS tissue phantoms.  

PubMed

Melanoma accounts for 75% of all skin cancer deaths. Pulsed photothermal radiometry (PPTR), optical coherence tomography (OCT) and ultrasound (US) are non-invasive imaging techniques that may be used to measure melanoma thickness, thus, determining surgical margins. We constructed a series of PDMS tissue phantoms simulating melanomas of different thicknesses. PPTR, OCT and US measurements were recorded from PDMS tissue phantoms and results were compared in terms of axial imaging range, axial resolution and imaging time. A Monte Carlo simulation and three-dimensional heat transfer model was constructed to simulate PPTR measurement. Experimental results show that PPTR and US can provide a wide axial imaging range (75 ?m-1.7 mm and 120-910 ?m respectively) but poor axial resolution (75 and 120 ?m respectively) in PDMS tissue phantoms, while OCT has the most superficial axial imaging range (14-450 ?m) but highest axial resolution (14 ?m). The Monte Carlo simulation and three-dimensional heat transfer model give good agreement with PPTR measurement. PPTR and US are suited to measure thicker melanoma lesions (>400 ?m), while OCT is better to measure thin melanoma lesions (<400 ?m). PMID:20954204

Wang, Tianyi; Mallidi, Srivalleesha; Qiu, Jinze; Ma, Li L; Paranjape, Amit S; Sun, Jingjing; Kuranov, Roman V; Johnston, Keith P; Milner, Thomas E

2011-05-01

168

Feasibility of optoacoustic visualization of high-intensity focused ultrasound-induced thermal lesions in live tissue  

PubMed Central

A 3-D optoacoustic imaging system was used to visualize thermal lesions produced in vivo using high-intensity focused ultrasound (HIFU). A 7.5-MHz, surgical, focused transducer with a radius of curvature of 35 mm and an aperture diameter of 23 mm was used to generate HIFU. A pulsed laser, which could operate at 755 nm and 1064 nm, was used to illuminate excised tissue and mice using a bifurcated fiber bundle resulting in two wide beams of light. Tomographic images were obtained while the specimens were rotated within a sphere outlined by a concave arc-shaped array of 64 piezo-composite transducers. These images were then combined to reconstruct 3-D volume images (voxel resolution 0.5 mm), which were acquired before and after HIFU exposure. In vivo optoacoustic images acquired at 1064 nm provided visualization of HIFU lesions. The lesion was indicated by a negative optoacoustic contrast. The molecular nature of such contrast may possibly be associated with reduction of the optical absorption due to reduced concentration of blood, tissue dehydration, denaturation of proteins and porphyrins, and reduction of thermoacoustic efficiency in the thermally treated tissue. These preliminary results demonstrate the potential of optoacoustic imaging to assess and monitor the progress of HIFU therapy. PMID:20459235

Chitnis, Parag V.; Brecht, Hans-Peter; Su, Richard; Oraevsky, Alexander A.

2010-01-01

169

An improved tissue-mimicking polyacrylamide hydrogel phantom for visualizing thermal lesions with high-intensity focused ultrasound.  

PubMed

A recipe was created to improve the tissue-mimicking (TM) bovine serum albumin (BSA) polyacrylamide hydrogel (PAG) reported in our previous study (Choi MJ, Guntur SR, Lee KI, Paeng DG, Coleman AJ. Ultrasound Med Biol 2013; 29:439-448). In that work, the concentration of acrylamide in TM BSA PAG was increased to make its attenuation coefficient the same as that of a tissue. However, this increase made the PAG stiffer and less homogeneous. In addition, the increase in acrylamide caused a significant increase in temperature over the denaturation threshold of BSA during polymerization, which required forced cooling so that the PAG did not become opaque at room temperature after polymerization. To eliminate those shortcomings, we substituted the increased acrylamide with a viscous polysaccharide liquid (corn syrup). The concentration of corn syrup was optimized to 20% (w/v, tested in the volume of 50 mL), so that the acoustic properties of the PAG would be close to those of human liver. The improved TM (iTM) BSA PAG constructed in this study had a speed of sound of 1588 ± 9 m/s, an attenuation coefficient of 0.51 ± 0.06 dB cm(-1) at 1 MHz and a backscattering coefficient of 0.22 ± 0.09 × 10(-3) sr(-1) cm(-1) MHz(-1). The density and acoustic impedance were 1057 kg/m(3) and 1.68 MRayl, respectively, and the non-linear parameter (B/A) was 5.9 ± 0.3. The thermal, optical and mechanical properties were almost the same as those of the BSA PAG (Lafon et al.2005). Experimental verification indicated that the thermal lesions visualized in the proposed iTM BSA PAG by high-intensity focused ultrasound were highly reproducible. In conclusion, iTM BSA PAG was proven to eliminate TM BSA PAG shortcomings effectively and is expected to be a promising test phantom for clinical high-intensity focused ultrasound device. PMID:25220272

Guntur, Sitaramanjaneya Reddy; Choi, Min Joo

2014-11-01

170

Analysis of the potential for coded excitation to improve the detection of tissue and blood motion in medical ultrasound  

E-print Network

Doppler ultrasound imaging modalities arguably represent one of the most complex task performed (usually in real time) by ultrasound scanners. At the heart of these techniques lies the ability to detect and estimate soft ...

Lamboul, Benjamin

2010-01-01

171

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

172

Scale Space Texture Classification Using Combined Classifiers with Application to Ultrasound Tissue Characterization  

E-print Network

tissue characterization for discrimination of normal liver from cirrhosis yields prom- ising results or at least one lobe is completely affected. In diffused liver diseases like cirrhosis, the texture of liver

Duin, Robert P.W.

173

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

174

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

175

Miniaturized fiber-optic ultrasound probes for endoscopic tissue analysis by micro-opto-mechanical technology.  

PubMed

A new Micro-Opto-Mechanical System (MOMS) technology for the fabrication of optoacoustic probes on optical fiber is presented. The technology is based on the thermoelastic emission of ultrasonic waves from patterned carbon films for generation and on extrinsic polymer Fabry-Perot acousto-optical transducers for detection, both fabricated on miniaturized single-crystal silicon frames used to mount the ultrasonic transducers on the tip of an optical fiber. Thanks to the fabrication process adopted, high miniaturization levels are reached in the MOMS devices, demonstrating fiber-optic emitters and detectors with minimum diameter around 350 and 250 ?m respectively. A thorough functional testing of the ultrasound emitters mounted on 200 and 600 ?m diameter optical fibers is presented, in which the fiber-optic emitter with a diameter of 200 ?m shows generated acoustic pressures with peak-to-peak value up to 2.8 MPa with rather flat emission spectra extended beyond 150 MHz. The possibility to use the presented optoacoustic sources in conjunction with the fiber-optic acousto-optical detectors within a minimally invasive probe is also demonstrated by successfully measuring the ultrasonic echo reflected from a rigid surface immersed in water with various concentration of scatterers. The resulting spectra highlight the possibility to discriminate the effects due to frequency selective attenuation in a very wide range of frequencies within a biological medium using the presented fiber-optic probes. PMID:24573502

Vannacci, E; Belsito, L; Mancarella, F; Ferri, M; Veronese, G P; Roncaglia, A; Biagi, E

2014-06-01

176

Ultrasound and photoacoustic imaging to monitor vascular growth in tissue engineered constructs  

Microsoft Academic Search

Quantitative and qualitative monitoring of neovascular growth is required in many vascular tissue engineering applications. For example, the contribution of progenitor cells in growing microvasculature has been demonstrated; however, the process of vascularization from progenitor cells is not well understood. Therefore, there is a need for an imaging technique that is consistent, easy to use, and can quantitatively assess the

Seung Yun Nam; Srivalleesha Mallidi; Ge Zhang; Laura J. Suggs; Stanislav Emelianov

2009-01-01

177

Influence of Temperature-Dependent Thermal Parameters on Temperature Elevation of Tissue Exposed to High-Intensity Focused Ultrasound: Numerical Simulation.  

PubMed

High-intensity focused ultrasound (HIFU) has been used successfully as a non-invasive modality in treating solid tumors. The temperature rise HIFU irradiation causes in a tissue depends on the thermal properties of the tissue. This study was motivated by our observation that the thermal properties of a tissue vary significantly with temperature (Guntur SR, Lee KI, Paeng DG, Coleman AJ, Choi MJ. Ultrasound Med Biol 2013;39:1771-1784). This research investigated how significantly the alteration of tissue thermal parameters, in the ranges of values measured at 25°C-90°C, affects prediction of the temperature elevation of tissue under the same HIFU exposure. The numerical simulation was performed by coupling a non-linear Khokhlov-Zabolotskaya-Kuznetsov equation with a bio-heat transfer function. In the conventional method of prediction, the thermal parameters were set as constants measured at room temperature (25°C). This study compared the conventional prediction with those predicted with different thermal parameters measured at the various temperatures up to 90°C. The results indicated that the conventional method significantly overestimated the rise in focal temperature in the liver tissue exposed to a clinical HIFU field, compared with the prediction made using thermal parameters measured at temperatures that cause thermal denaturation. This finding suggests that temperature-dependent thermal parameters should be considered in predicting the temperature rise in a tissue to avoid use of an insufficient thermal dose in treatment planning for HIFU surgery. PMID:25638316

Guntur, Sitaramanjaneya Reddy; Choi, Min Joo

2015-03-01

178

[Treatment of a solitary adenoma of the parathyroid gland with ultrasound-guided percutaneous Radio-Frequency-Tissue-Ablation (RFTA)].  

PubMed

Radio-Frequency-Tissue-Ablation (RFTA) for the treatment of primary and secondary tumours of the liver has been used for several years, but this minimally invasive treatment is not limited to the liver. A patient suffering from symptomatic postmenopausal osteoporosis, additionally having primary hyperparathyroidism since 1995, refused a surgical resection of the adenoma of the parathyroid gland. Sonographically a 16 mm hypoechoic tumour dorsal of the right upper pole of the thyroid gland was detected. Osteodensitometry: severe osteoporosis of the lumbar spine (88 % of the norm for this age group). Blood check: Elevation of serum calcium level (3.1mmol/l) and serum parathormone level 274 pg/dl (N: 10-50). A percutaneous ultrasound guided RFTA of the adenoma of the thyroid gland was carried out. After RFTA the serum parathormone levels and the serum calcium levels dropped back to normal. The patient was followed-up for one year. For the first time a sufficient therapy for osteoporosis comprising calcium, etidronate and cholecalciferol could be carried out. The osteodensitometry carried out one year after treatment showed an increase in bone density. For the treatment of symptomatic primary hyperparathyroidism RFTA can be a therapeutic alternative for patients with contraindications for surgery. PMID:12168145

Hänsler, J; Harsch, I A; Strobel, D; Hahn, E G; Becker, D

2002-06-01

179

Correlation of Femoral and Lumbar DXA and Calcaneal Ultrasound, Measured In Situ with Intact Soft Tissues, with the In Vitro Failure Loads of the Proximal Femur  

Microsoft Academic Search

:   The objective of this study was to determine experimentally the sex-specific correlation of femoral and lumbar DXA and calcaneal\\u000a ultrasound, measured in situ, with the in vitro failure loads of the proximal femur. Fifty-eight cadavers with intact skin\\u000a and soft tissues (34 male, aged 81.2 ± 8.7 years; 24 female, aged 83.7 ± 10.6 years) were examined. The bone

E.-M. Lochmüller; J.-B. Zeller; D. Kaiser; F. Eckstein; J. Landgraf; R. Putz; R. Steldinger

1998-01-01

180

Study on the refractive index matching effect of ultrasound on optical clearing of bio-tissues based on the derivative total reflection method.  

PubMed

In recent years, the tissue optical clearing (OC) technique in the biomedicine field has drawn lots of attention. Various physical and chemical methods have been introduced to improve the efficacy of OC. In this study, the effect of the combination of glycerol and ultrasound treatment on OC of in vitro porcine muscle tissues has been investigated. The refractive index (RI) matching mechanism of OC was directly observed based on the derivative total reflection method. A theoretical model was used to simulate the proportion of tissue fluid in the illuminated area. Moreover, the total transmittance spectra have been obtained by a spectrometer over the range from 450 nm to 700 nm. The administration of glycerol and ultrasound has led to an increase of the RI of background medium and a more RI matching environment was achieved. The experimental results support the validity of the ultrasound treatment for OC. The RI matching mechanism has been firstly quantitatively analyzed based on the derivative total reflection method. PMID:25360366

Zeng, Huanhuan; Wang, Jin; Ye, Qing; Deng, Zhichao; Mei, Jianchun; Zhou, Wenyuan; Zhang, Chunping; Tian, Jianguo

2014-10-01

181

Study on the refractive index matching effect of ultrasound on optical clearing of bio-tissues based on the derivative total reflection method  

PubMed Central

In recent years, the tissue optical clearing (OC) technique in the biomedicine field has drawn lots of attention. Various physical and chemical methods have been introduced to improve the efficacy of OC. In this study, the effect of the combination of glycerol and ultrasound treatment on OC of in vitro porcine muscle tissues has been investigated. The refractive index (RI) matching mechanism of OC was directly observed based on the derivative total reflection method. A theoretical model was used to simulate the proportion of tissue fluid in the illuminated area. Moreover, the total transmittance spectra have been obtained by a spectrometer over the range from 450 nm to 700 nm. The administration of glycerol and ultrasound has led to an increase of the RI of background medium and a more RI matching environment was achieved. The experimental results support the validity of the ultrasound treatment for OC. The RI matching mechanism has been firstly quantitatively analyzed based on the derivative total reflection method. PMID:25360366

Zeng, Huanhuan; Wang, Jin; Ye, Qing; Deng, Zhichao; Mei, Jianchun; Zhou, Wenyuan; Zhang, Chunping; Tian, Jianguo

2014-01-01

182

Microbubble Type and Distribution Dependence of Focused Ultrasound Induced Blood Brain Barrier Opening  

PubMed Central

Focused Ultrasound (FUS) in the presence of microbubbles has been used to non-invasively induce reversible blood brain barrier (BBB) opening in both rodents and non-human primates. This study aims at identifying the dependence of the BBB opening properties on the polydisperse microbubble (since all clinically approved microbubbles are polydisperse) type and distribution by using clinically approved UCA (Definity®) and in-house made polydisperse microbubbles (IHP) in mice. A total of 18 C57BL/6 mice (n = 3) were used in this study, and each mouse received either Definity® or IHP microbubbles via tail vein injection. The concentration and size distribution of both the activated Definity® and IHP microbubbles were measured and diluted to 6×108/ml prior to injection. Immediately after the microbubble administration, FUS sonications were carried out with the following parameters: frequency of 1.5 MHz, pulse repetition frequency of 10 Hz, 1000 cycles, in situ peak rarefactional acoustic pressures of 0.3 MPa, 0.45 MPa, and 0.6 MPa for a sonication duration of 60 s. Contrast-enhanced magnetic resonance imaging (MRI) was used to confirm the BBB opening and allowed for image-based analysis. The permeability of the treated region and volumes of BBB opening using the two types of microbubbles did not show significant difference (P > 0.05) for PRPs of 0.45 MPa and 0.6 MPa, while IHP microbubbles showed significantly higher permeability and volume of opening (P < 0.05) at the relatively lower pressure of 0.3 MPa. The results from this study indicate that the microbubble type and distribution could have significant effects on the FUS-induced BBB opening at lower, but less important at higher, pressure levels, possibly due to the stable cavitation that governs the former. This difference may have become less significant at higher FUS pressure levels where inertial cavitation typically occurs. PMID:24239362

Wang, Shutao; Samiotaki, Gesthimani; Olumolade, Oluyemi; Feshitan, Jameel A.; Konofagou, Elisa E.

2014-01-01

183

Overexpression of type VI collagen in neoplastic lung tissues  

PubMed Central

Type VI collagen (COL6), an extracellular matrix protein, is important in maintaining the integrity of lung tissue. An increase in COL6 mRNA and protein deposition was found in the lungs of patients with pulmonary fibrosis, a chronic inflammatory condition with a strong association with lung cancer. In the present study, we demonstrated overexpression of COL6 in the lungs of non-small cell lung cancers. We hypothesized that excessive COL6 in the lung interstitium may exert stimulatory effects on the adjacent cells. In vitro stimulation of monocytes with COL6 resulted in the production of IL-23, which may promote tumor development in an environment of IL-23-mediated lung inflammation, where tissue modeling occurs concurrently with excessive COL6 production. In addition, COL6 was capable of stimulating signaling pathways that activate focal adhesion kinase and extracellular signal-regulated kinase 1/2 in lung epithelial cells, which may also facilitate the development of lung neoplasms. Taken together, our data suggest the potential role of COL6 in promoting lung neoplasia in diseased lungs where COL6 is overexpressed. PMID:25176343

VOILES, LARRY; LEWIS, DAVID E.; HAN, LING; LUPOV, IVAN P.; LIN, TSANG-LONG; ROBERTSON, MICHAEL J.; PETRACHE, IRINA; CHANG, HUA-CHEN

2014-01-01

184

Overexpression of type VI collagen in neoplastic lung tissues.  

PubMed

Type VI collagen (COL6), an extracellular matrix protein, is important in maintaining the integrity of lung tissue. An increase in COL6 mRNA and protein deposition was found in the lungs of patients with pulmonary fibrosis, a chronic inflammatory condition with a strong association with lung cancer. In the present study, we demonstrated overexpression of COL6 in the lungs of non-small cell lung cancers. We hypothesized that excessive COL6 in the lung interstitium may exert stimulatory effects on the adjacent cells. In vitro stimulation of monocytes with COL6 resulted in the production of IL-23, which may promote tumor development in an environment of IL-23-mediated lung inflammation, where tissue modeling occurs concurrently with excessive COL6 production. In addition, COL6 was capable of stimulating signaling pathways that activate focal adhesion kinase and extracellular signal?regulated kinase 1/2 in lung epithelial cells, which may also facilitate the development of lung neoplasms. Taken together, our data suggest the potential role of COL6 in promoting lung neoplasia in diseased lungs where COL6 is overexpressed. PMID:25176343

Voiles, Larry; Lewis, David E; Han, Ling; Lupov, Ivan P; Lin, Tsang-Long; Robertson, Michael J; Petrache, Irina; Chang, Hua-Chen

2014-11-01

185

Noninvasive pulsed focused ultrasound allows spatiotemporal control of targeted homing for multiple stem cell types in murine skeletal muscle and the magnitude of cell homing can be increased through repeated applications  

PubMed Central

Stem cells are promising therapeutics for cardiovascular diseases and intravenous injection is the most desirable route of administration clinically. Subsequent homing of exogenous stem cells to pathological loci is frequently required for therapeutic efficacy and is mediated by chemo attractants (cell adhesion molecules, cytokines, and growth factors). Homing processes are inefficient and depend on short-lived pathological inflammation that limits the window of opportunity for cell injections. Noninvasive pulsed focused ultrasound (plus), which emphasizes mechanical ultrasound-tissue interactions, can be precisely targeted in the body and is a promising approach to target and maximize stem cell delivery by stimulating chemo attractant expression in plus-treated tissue prior to cell infusions. We demonstrate that plus is nondestructive to marine skeletal muscle tissue (no necrosis, hemorrhage, or muscle stem cell activation) and initiates a largely M2-type macrophage response. We also demonstrate local up regulation of chemo attractants in plus-treated skeletal muscle leads to enhance homing, permeability, and retention of human mesenchymal stem cells (MSC) and human endothelial precursor cells (EPC). Furthermore, the magnitude of MSC or EPC homing was increased when plus treatments and cell infusions were repeated daily. This study demonstrates that plus defines transient “molecular zip codes” of elevated chemo attractants in targeted muscle tissue, which effectively provides spatiotemporal control and tenability of the homing process for multiple stem cell types. plus is a clinically-translatable modality that may ultimately improve homing efficiency and flexibility of cell therapies for cardiovascular diseases. PMID:23922277

Burks, Scott R.; Ziadloo, Ali; Kim, Saejeong J.; Nguyen, Ben A.; Frank, Joseph A.

2013-01-01

186

The Speed of Sound and Attenuation of an IEC Agar-Based Tissue-Mimicking Material for High Frequency Ultrasound Applications  

PubMed Central

This study characterized the acoustic properties of an International Electromechanical Commission (IEC) agar-based tissue mimicking material (TMM) at ultrasound frequencies in the range 10–47 MHz. A broadband reflection substitution technique was employed using two independent systems at 21°C ± 1°C. Using a commercially available preclinical ultrasound scanner and a scanning acoustic macroscope, the measured speeds of sound were 1547.4 ± 1.4 m?s?1 and 1548.0 ± 6.1 m?s?1, respectively, and were approximately constant over the frequency range. The measured attenuation (dB?cm?1) was found to vary with frequency f (MHz) as 0.40f + 0.0076f2. Using this polynomial equation and extrapolating to lower frequencies give values comparable to those published at lower frequencies and can estimate the attenuation of this TMM in the frequency range up to 47 MHz. This characterisation enhances understanding in the use of this TMM as a tissue equivalent material for high frequency ultrasound applications. PMID:22502881

Sun, Chao; Pye, Stephen D.; Browne, Jacinta E.; Janeczko, Anna; Ellis, Bill; Butler, Mairead B.; Sboros, Vassilis; Thomson, Adrian J.W.; Brewin, Mark P.; Earnshaw, Charles H.; Moran, Carmel M.

2012-01-01

187

Visibility of foreign bodies in soft tissue in plain radiographs, computed tomography, magnetic resonance imaging, and ultrasound. An in vitro study.  

PubMed

We compared conventional plain radiography, computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound (US) with respect to their suitability for detecting foreign bodies in soft tissue in an in vitro model using a cow tongue to simulate orofacial soft tissues. Four samples of different sizes of fractured tooth crown, pieces of amalgam, glass, asphalt, composite, dry wood, and stone were each embedded under a 2-cm-thick flap on the caudal surface of the tongue. Plain radiographs revealed all the materials except wood, and there was some variation in the subjectively evaluated radiopacity of the materials which indicated the nature of the foreign bodies concerned. MRI proved to be the least suitable imaging method, as particles with a metallic content gave rise to powerful interference artifacts. CT and especially US proved to be suitable imaging methods for foreign-body detection in soft tissue. Amalgam produced a metallic streaking artifact in CT, which visualized wood as gas density, and depicted all the other materials as similar hyperdense masses. Ultrasound was both sensitive and specific in detecting foreign bodies in soft tissue. The particles were better defined in form and size with CT and US than with MRI or plain radiography. We conclude that when plain radiographs, history, and clinical examination fail to reveal the presence of superficial foreign bodies, US or CT can serve as an alternative method. PMID:8320449

Oikarinen, K S; Nieminen, T M; Mäkäräinen, H; Pyhtinen, J

1993-04-01

188

Quantitative ultrasound and vertebral fractures in patients with type 2 diabetes.  

PubMed

Patients with type 2 diabetes (T2DM) are known to have increased risks of femoral neck and vertebral fractures, although their bone mineral density (BMD) is normal or even slightly increased compared to non-DM controls. This observation suggests that bone fragility not reflected by BMD, possibly deterioration of bone quality, may participate in their fracture risks. Quantitative ultrasound (QUS), unlike BMD, could possibly evaluate bone quality, especially the microarchitecture, and therefore may be useful for assessing fracture risk in T2DM. To test this hypothesis, we measured calcaneal QUS as well as BMD at the lumbar spine, femoral neck, and 1/3 radius in 96 women (mean age 66.6 years old) and 99 men (64.7 years old) with T2DM, and examined their associations with prevalent vertebral fractures (VFs). Calcaneal QUS was performed by CM-200 (Elk Corp., Osaka, Japan), and speed of sound (SOS) values were obtained. BMD was measured by QDR4500 (Hologic, Waltham, MA). In T2DM patients, VFs were found in 33 and 45 subjects in women and men, respectively. When compared between subjects with and without VFs, there were no significant differences in values of SOS or BMD at any site between the groups in either gender. The distribution of SOS as a function of age showed that those with VFs were scattered widely, and there were no SOS thresholds for VFs in either gender. Logistic regression analysis adjusted for age and BMI showed that either SOS or BMD was not significantly associated with the presence of VFs in either gender. These results show that QUS as well as BMD are unable to discriminate T2DM patients with prevalent VFs from those without VFs. It seems necessary to seek other imaging modalities or biochemical markers evaluating bone fragility and fracture risk in T2DM. PMID:21437613

Yamaguchi, Toru; Yamamoto, Masahiro; Kanazawa, Ippei; Yamauchi, Mika; Yano, Shozo; Tanaka, Nobuko; Nitta, Eri; Fukuma, Asako; Uno, Seiko; Sho-no, Tomoko; Sugimoto, Toshitsugu

2011-09-01

189

Anterior thigh composition measured using ultrasound imaging to quantify relative thickness of muscle and non-contractile tissue: a potential biomarker for musculoskeletal health.  

PubMed

This study aimed to use ultrasound imaging to provide objective data on the effects of ageing and gender on relative thickness of quadriceps muscle and non-contractile tissue thickness (subcutaneous fat, SF, combined with perimuscular fascia). In 136 healthy males and females (aged 18-90?years n = 63 aged 18-35?years; n = 73 aged 65-90) images of the anterior thigh (dominant) were taken in relaxed supine using B-mode ultrasound imaging. Thickness of muscle, SF and perimuscular fascia were measured, and percentage thickness of total anterior thigh thickness calculated. Independent t-tests compared groups. Correlation between tissue thickness and BMI was examined using Pearson's coefficient. Muscle thickness was: 39? ± ?8?mm in young males, 29? ± ?6?mm in females, 25? ± ?4?mm in older males and 20? ± ?5?mm in females. Percentage muscle to thigh thickness was greater in young participants (p = 0.001). Percentage SF and fascia was 17? ± ?6% in young and 26? ± ?8% in older males, 32? ± ?7% in young and 44? ± ?7% in older females. BMI was similar for age and correlated moderately with non-contractile tissue (r = 0.54; p < 0.001) and poorly with muscle (r = -0.01; p = 0.93). In conclusion, this novel application of ultrasound imaging as a simple and rapid means of assessing thigh composition (relative thickness of muscle and non-contractile tissue) may help inform health status, e.g. in older people at risk of frailty and loss of mobility, and aid monitoring effects of weight loss or gain, deconditioning and exercise. PMID:25243984

Agyapong-Badu, Sandra; Warner, Martin; Samuel, Dinesh; Narici, Marco; Cooper, Cyrus; Stokes, Maria

2014-10-01

190

Finite element modeling of tissue for optimal ultrasonic transducer array design  

Microsoft Academic Search

Tissue characterization using ultrasound scattering has been routinely used to extract the cellular properties of tissue. Ultrasonic backscattered radio frequency (RF) data is analyzed to provide estimates of the size, shape and concentration of a wide range of tissues. These tissue parameters form a feature space that can be used to discriminate between tissue types as well as indicate the

Clyde Clarke; D. Carl White; Ralph Etienne-cummings

2008-01-01

191

Effect of biological characteristics of different types of uterine fibroids, as assessed with t2-weighted magnetic resonance imaging, on ultrasound-guided high-intensity focused ultrasound ablation.  

PubMed

The aims of this study were to assess the effects of the biological characteristics of different types of uterine fibroids, as assessed with T2-weighted magnetic resonance imaging (MRI), on ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation. Thirty-five patients with 39 symptomatic uterine fibroids who underwent myomectomy or hysterectomy were enrolled. Before surgery, the uterine fibroids were subdivided into hypo-intense, iso-intense, heterogeneous hyper-intense and homogeneous hyper-intense categories based on signal intensity on T2-weighted MRI. Tissue density and moisture content were determined in post-operative samples and normal uterine tissue, the isolated uterine fibroids were subjected to USgHIFU, and the extent of ablation was measured using triphenyltetrazolium chloride. Hematoxylin and eosin staining and sirius red staining were undertaken to investigate the organizational structure of the uterine fibroids. Estrogen and progesterone receptor expression was assayed via immunohistochemical staining. The mean diameter of uterine fibroids was 6.9 ± 2.8 cm. For all uterine fibroids, the average density and moisture content were 10.7 ± 0.7 mg/mL and 75.7 ± 2.4%, respectively; and for the homogeneous hyper-intense fibroids, 10.3 ± 0.5 mg/mL and 76.6 ± 2.3%. The latter subgroup had lower density and higher moisture content compared with the other subgroups. After USgHIFU treatment, the extent of ablation of the hyper-intense fibroids was 102.7 ± 42.1 mm(2), which was significantly less than those of the hypo-intense and heterogeneous hyper-intense fibroids. Hematoxylin and eosin staining and sirius red staining revealed that the homogeneous hyper-intense fibroids had sparse collagen fibers and abundant cells. Immunohistochemistry results revealed that estrogen and progesterone receptors were highly expressed in the homogeneous hyper-intense fibroids. This study revealed that lower density, higher moisture content, sparse collagen fibers, abundant cells and overexpression of estrogen and progesterone receptors are important biological characteristics that resulted in poor efficacy in the treatment of homogeneous hyper-intense fibroids. PMID:25542494

Zhao, Wen-Peng; Chen, Jin-Yun; Chen, Wen-Zhi

2015-02-01

192

Influence of different sized nanoparticles combined with ultrasound on the optical properties of in vitro normal and cancerous human lung tissue studied with OCT and diffuse reflectance spectra  

NASA Astrophysics Data System (ADS)

The present study is concerned with the in vitro study of different sized titanium dioxide (TiO2) nanoparticles’ (NPs) penetration and accumulation in human normal lung (NL) tissue and lung adenocarcinoma tumor (LAT) tissue by the methods of continuous optical coherence tomography (OCT) monitoring and diffuse reflectance (DR) spectra measurement, and their evaluating the effects of TiO2 NPs in two sizes (60?nm and 100?nm) and their combination with ultrasound (US) on the optical properties of human NL and LAT tissue. Spectral measurements indicate that TiO2 NPs penetrate and accumulate into the tissues and thus induce enhancement of DR. The averaged and normalized OCT signal intensity suggests that light penetration depth is significantly enlarged by ultrasound. The average attenuation coefficient of NL tissue changes from 5.10? ± ?0.26?mm?1 to 3.12? ± ?0.43?mm?1 and 2.15? ± ?0.54?mm?1 at 120?min for 60?nm TiO2 NPs and 60?nm TiO2NPs/US treatment, respectively, and from 5.54? ± ?0.46?mm?1 to 3.24? ± ?0.73?mm?1 and 2.69? ± ?0.34?mm?1 at 150?min for 100?nm TiO2 NPs and 100?nm TiO2NPs/US, respectively. The average attenuation coefficient of LAT tissue changes from 9.12? ± ?0.54?mm?1 to 4.54? ± ?0.39?mm?1 and 3.61? ± ?0.38?mm?1 at 120?min for 60?nm TiO2 NPs and 60?nm TiO2NPs/US treatment, respectively, and from 9.79? ± ?0.32?mm?1 to 5.12? ± ?0.47?mm?1 and 4.89? ± ?0.59?mm?1 at 150?min for 100?nm TiO2 NPs and 100?nm TiO2NPs/US, respectively. The results suggest that the optical properties of NL and LAT tissues are greatly influenced by TiO2 NPs and their combination with ultrasound.

Zhou, L. P.; Wu, G. Y.; Wei, H. J.; Guo, Z. Y.; Yang, H. Q.; He, Y. H.; Xie, S. S.; Liu, Y.

2014-11-01

193

Simplified and miniaturized procedure based on ultrasound-assisted cytosol preparation for the determination of Cd and Cu bound to metallothioneins in mussel tissue by ICP-MS.  

PubMed

A simplified and miniaturized procedure for the determination of Cd and Cu bound to metallothioneins (MTs) by ICP-MS in mussel tissue has been developed. Cytosol preparation was based on the indirect sonication of slurries containing the lyophilized sample dispersed in 1 mL of extractant by means of a sonoreactor Cup-Horn. Rabbit liver MTs (Apo-MT-I, Apo-MT-II and Cd(7)-MT-II) and a conventional cytosol preparation procedure were used for validation purposes. The usual heating step and additional centrifugations of the conventional procedure for cytosol preparation can be omitted when using ultrasound treatment. The possible effect of denaturation on MTs and its effect on the metal bound to MTs were evaluated. Variables influencing the ultrasound-assisted cytosol preparation procedure were carefully optimized for simultaneous determination of both metals. Chromatographic conditions to separate the MT fraction from other proteins present in cytosols were also studied. Six samples can be processed within 3 min of sonication. An acid ultrasound-assisted extraction procedure with diluted acid was also proposed for determining total Cd and Cu. Finally, Cd and Cu bound to MTs as well as total Cd and Cu were determined in mussels from Pontevedra and Ares-Betanzos coastal inlets (Galicia, Spain). PMID:22483885

Lavilla, Isela; Costas, Marta; Gil, Sandra; Corderí, Sandra; Sánchez, Goretti; Bendicho, Carlos

2012-05-15

194

An endothelial storage granule for tissue-type plasminogen activator.  

PubMed

In previous studies we have shown that, after stimulation by a receptor ligand such as thrombin, tissue-type plasminogen activator (tPA) and von Willebrand factor (vWf) will be acutely released from human umbilical vein endothelial cells (HUVEC). However, the mechanisms involved in the secretion of these two proteins differ in some respects, suggesting that the two proteins may be stored in different secretory granules. By density gradient centrifugation of rat lung homogenates, a particle was identified that contained nearly all tPA activity and antigen. This particle had an average density of 1.11-1.12 g/ml, both in Nycodenz density gradients and in sucrose density gradients. A similar density distribution of tPA was found for a rat endothelial cell line and for HUVEC. After thrombin stimulation of HUVEC to induce tPA secretion, the amount of tPA present in high-density fractions decreased, concomitant with the release of tPA into the culture medium and a shift in the density distribution of P-selectin. vWf, known to be stored in Weibel-Palade bodies, showed an identical distribution to tPA in Nycodenz gradients. In contrast, the distribution in sucrose gradients of vWf from both rat and human lung was very different from that of tPA, suggesting that tPA and vWf were not present in the same particle. Using double-immunofluorescence staining of HUVEC, tPA- and vWf-containing particles showed a different distribution by confocal microscopy. The distribution of tPA also differed from the distribution of tissue factor pathway inhibitor, endothelin-1, and caveolin. By immunoelectronmicroscopy, immunoreactive tPA could be demonstrated in small vesicles morphologically different from the larger Weibel-Palade bodies. It is concluded that tPA in endothelial cells is stored in a not-previously-described, small and dense (d = 1.11-1.12 g/ml) vesicle, which is different from a Weibel-Palade body. PMID:9314543

Emeis, J J; van den Eijnden-Schrauwen, Y; van den Hoogen, C M; de Priester, W; Westmuckett, A; Lupu, F

1997-10-01

195

An Endothelial Storage Granule for Tissue-Type Plasminogen Activator  

PubMed Central

In previous studies we have shown that, after stimulation by a receptor ligand such as thrombin, tissue-type plasminogen activator (tPA) and von Willebrand factor (vWf) will be acutely released from human umbilical vein endothelial cells (HUVEC). However, the mechanisms involved in the secretion of these two proteins differ in some respects, suggesting that the two proteins may be stored in different secretory granules. By density gradient centrifugation of rat lung homogenates, a particle was identified that contained nearly all tPA activity and antigen. This particle had an average density of 1.11–1.12 g/ml, both in Nycodenz density gradients and in sucrose density gradients. A similar density distribution of tPA was found for a rat endothelial cell line and for HUVEC. After thrombin stimulation of HUVEC to induce tPA secretion, the amount of tPA present in high-density fractions decreased, concomitant with the release of tPA into the culture medium and a shift in the density distribution of P-selectin. vWf, known to be stored in Weibel-Palade bodies, showed an identical distribution to tPA in Nycodenz gradients. In contrast, the distribution in sucrose gradients of vWf from both rat and human lung was very different from that of tPA, suggesting that tPA and vWf were not present in the same particle. Using double-immunofluorescence staining of HUVEC, tPA- and vWf-containing particles showed a different distribution by confocal microscopy. The distribution of tPA also differed from the distribution of tissue factor pathway inhibitor, endothelin-1, and caveolin. By immunoelectronmicroscopy, immunoreactive tPA could be demonstrated in small vesicles morphologically different from the larger Weibel-Palade bodies. It is concluded that tPA in endothelial cells is stored in a not-previously-described, small and dense (d = 1.11– 1.12 g/ml) vesicle, which is different from a Weibel-Palade body. PMID:9314543

Emeis, J.J.; Eijnden-Schrauwen, Y. van den; Hoogen, C.M. van den; Priester, W. de; Westmuckett, A.; Lupu, F.

1997-01-01

196

High intensity focused ultrasound (HIFU) and ethanol induced tissue ablation: Thermal lesion volume and temperature ex vivo  

NASA Astrophysics Data System (ADS)

HIFU is the upcoming technology for noninvasive or minimally invasive tumor ablation via the localized acoustic energy deposition at the focal region within the tumor target. The presence of cavitation bubbles had been shown to improve the therapeutic effect of HIFU. In this study, we have investigated the effect of HIFU on temperature rise and cavitation bubble activity in ethanol-treated porcine liver and kidney tissues. We have also explored changes in the viability and proliferation rate of HepG2, SW1376, and FB1 cancer cells with their exposure to ethanol and HIFU. Tissues were submerged in 95% ethanol for five hours and then exposed to HIFU generated by a 1.1 MHz transducer or injected into focal spot before HIFU exposure. Cavitation events were measured by a passive cavitation detection technique for a range of acoustic power from 1.17 W to 20.52 W. The temperature around the focal zone was measured by type K or type E thermocouples embedded in the samples. In experiments with cancer cells, 2.7 millions cells were treated with concentration of ethanol at concentration 2%, 4%, 10%, 25%, and 50% and the cell were exposed to HIFU with power of 2.73 W, 8.72 W, and 12.0 W for 30 seconds. Our data show that the treatment of tissues with ethanol reduces the threshold power for inertial cavitation and increases the temperature rise. The exposure of cancer cells to various HIFU power only showed a higher number of viable cells 24 to 72 hours after HIFU exposure. On the other hand, both the viability and proliferation rate were significantly decreased in cells treated with ethanol and then HIFU at 8.7 W and 12.0 W even at ethanol concentration of 2 and 4 percent. In conclusion, the results of our study indicate that percutaneous ethanol injection (PEI) and HIFU have a synergistic effect on cancer cells ablation.

Hoang, Nguyen Hai

197

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., Jr.; Liu, Frank W.; Stevenson, David K.; Kermit, Eben L.

1997-12-01

198

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

199

Musculoskeletal interventional ultrasound.  

PubMed

Ultrasound is a nonionizing, low-cost, portable imaging technique for the evaluation of tendons, muscles, joints, soft tissue masses, and cysts, especially in patients unable to tolerate computed tomography or magnetic resonance imaging. These advantages make ultrasound an ideal modality for guiding musculoskeletal interventions. Its real-time capabilities allow continuous observation of needle placement into the targeted area and direct visualization of interventions such as injection of medication while avoiding other soft tissue structures or nearby neurovascular bundles. After a brief overview of the technical factors involved in performing ultrasound-guided musculoskeletal interventions, this article reviews commonly performed percutaneous procedures in the musculoskeletal system. PMID:18095250

Joines, Melissa M; Motamedi, Kambiz; Seeger, Leanne L; DiFiori, John P

2007-06-01

200

Tissue cryobanking for conservation programs: effect of tissue type and storage time after death.  

PubMed

In this study, we investigated the temporal post-mortem limits, within which there will be guarantees of obtaining living cells from several tissues of sheep and cattle and the effect of vitrification on the ability of cells from tissue stored at different times. Muscle tissue and auricular cartilage were stored at 4°C for 5, 48, 72, 96 and 216 h post-mortem (hpm). Tissue samples were sorted into two groups: one group was in vitro cultured immediately after storage and the other was vitrified after storage and then in vitro cultured. In cattle and sheep, no differences in subconfluence rates were observed between the two experimental groups. At the same time, no significant differences were observed in the number of days required in culture to reach confluence between non-vitrified and vitrified groups when tissues were stored at 4°C for different times. In sheep, while the population doubling times (PDT) were similar in cartilage cells from vitrified and non-vitrified tissues and stored at 4°C for 5 and 216 hpm, PDT of muscle cells were longer in 216 hpm stored groups than in 5 hpm stored groups. In bovine, although the PDT of muscle cells were similar for 5 and 216 hpm and both vitrified and non-vitrified tissues and the PDT were longer in cartilage cells from vitrified than from non-vitrified tissues. In conclusion, although storage times and vitrification have different effects on tissues from cattle and sheep, this study showed that living cells could be obtained from all groups. Therefore, cartilage and muscle tissues can be stored at 4°C for 216 hpm and used for cyrobanking. PMID:22271151

Caputcu, Arzu Tas; Akkoc, Tolga; Cetinkaya, Gaye; Arat, Sezen

2013-03-01

201

Determination and Quantification of Collagen Types in Tissues Using HPLC-MS\\/MS  

Microsoft Academic Search

A method for the determination and quantification of collagen types (I - V) using sample pretreatment has been developed. This work is a continuation of our previous work dealing with the determination of collagen types I and III in tissues (1). The tissues (rat placenta and porcine cartilage) were firstly homogenized with a pestle in a grinding mortar with liquid

Statis Pataridis; Adam Eckhardt; Katerina Mikulikova; Pavla Sedlakova; Ivan Miksik

2009-01-01

202

3D conformal MRI-controlled transurethral ultrasound prostate therapy: validation of numerical simulations and demonstration in tissue-mimicking gel phantoms.  

PubMed

MRI-controlled transurethral ultrasound therapy uses a linear array of transducer elements and active temperature feedback to create volumes of thermal coagulation shaped to predefined prostate geometries in 3D. The specific aims of this work were to demonstrate the accuracy and repeatability of producing large volumes of thermal coagulation (>10 cc) that conform to 3D human prostate shapes in a tissue-mimicking gel phantom, and to evaluate quantitatively the accuracy with which numerical simulations predict these 3D heating volumes under carefully controlled conditions. Eleven conformal 3D experiments were performed in a tissue-mimicking phantom within a 1.5T MR imager to obtain non-invasive temperature measurements during heating. Temperature feedback was used to control the rotation rate and ultrasound power of transurethral devices with up to five 3.5 × 5 mm active transducer elements. Heating patterns shaped to human prostate geometries were generated using devices operating at 4.7 or 8.0 MHz with surface acoustic intensities of up to 10 W cm(-2). Simulations were informed by transducer surface velocity measurements acquired with a scanning laser vibrometer enabling improved calculations of the acoustic pressure distribution in a gel phantom. Temperature dynamics were determined according to a FDTD solution to Pennes' BHTE. The 3D heating patterns produced in vitro were shaped very accurately to the prostate target volumes, within the spatial resolution of the MRI thermometry images. The volume of the treatment difference falling outside ± 1 mm of the target boundary was, on average, 0.21 cc or 1.5% of the prostate volume. The numerical simulations predicted the extent and shape of the coagulation boundary produced in gel to within (mean ± stdev [min, max]): 0.5 ± 0.4 [-1.0, 2.1] and -0.05 ± 0.4 [-1.2, 1.4] mm for the treatments at 4.7 and 8.0 MHz, respectively. The temperatures across all MRI thermometry images were predicted within -0.3 ± 1.6 °C and 0.1 ± 0.6 °C, inside and outside the prostate respectively, and the treatment time to within 6.8 min. The simulations also showed excellent agreement in regions of sharp temperature gradients near the transurethral and endorectal cooling devices. Conformal 3D volumes of thermal coagulation can be precisely matched to prostate shapes with transurethral ultrasound devices and active MRI temperature feedback. The accuracy of numerical simulations for MRI-controlled transurethral ultrasound prostate therapy was validated experimentally, reinforcing their utility as an effective treatment planning tool. PMID:21030751

Burtnyk, Mathieu; N'Djin, William Apoutou; Kobelevskiy, Ilya; Bronskill, Michael; Chopra, Rajiv

2010-11-21

203

3D conformal MRI-controlled transurethral ultrasound prostate therapy: validation of numerical simulations and demonstration in tissue-mimicking gel phantoms  

NASA Astrophysics Data System (ADS)

MRI-controlled transurethral ultrasound therapy uses a linear array of transducer elements and active temperature feedback to create volumes of thermal coagulation shaped to predefined prostate geometries in 3D. The specific aims of this work were to demonstrate the accuracy and repeatability of producing large volumes of thermal coagulation (>10 cc) that conform to 3D human prostate shapes in a tissue-mimicking gel phantom, and to evaluate quantitatively the accuracy with which numerical simulations predict these 3D heating volumes under carefully controlled conditions. Eleven conformal 3D experiments were performed in a tissue-mimicking phantom within a 1.5T MR imager to obtain non-invasive temperature measurements during heating. Temperature feedback was used to control the rotation rate and ultrasound power of transurethral devices with up to five 3.5 × 5 mm active transducer elements. Heating patterns shaped to human prostate geometries were generated using devices operating at 4.7 or 8.0 MHz with surface acoustic intensities of up to 10 W cm-2. Simulations were informed by transducer surface velocity measurements acquired with a scanning laser vibrometer enabling improved calculations of the acoustic pressure distribution in a gel phantom. Temperature dynamics were determined according to a FDTD solution to Pennes' BHTE. The 3D heating patterns produced in vitro were shaped very accurately to the prostate target volumes, within the spatial resolution of the MRI thermometry images. The volume of the treatment difference falling outside ±1 mm of the target boundary was, on average, 0.21 cc or 1.5% of the prostate volume. The numerical simulations predicted the extent and shape of the coagulation boundary produced in gel to within (mean ± stdev [min, max]): 0.5 ± 0.4 [-1.0, 2.1] and -0.05 ± 0.4 [-1.2, 1.4] mm for the treatments at 4.7 and 8.0 MHz, respectively. The temperatures across all MRI thermometry images were predicted within -0.3 ± 1.6 °C and 0.1 ± 0.6 °C, inside and outside the prostate respectively, and the treatment time to within 6.8 min. The simulations also showed excellent agreement in regions of sharp temperature gradients near the transurethral and endorectal cooling devices. Conformal 3D volumes of thermal coagulation can be precisely matched to prostate shapes with transurethral ultrasound devices and active MRI temperature feedback. The accuracy of numerical simulations for MRI-controlled transurethral ultrasound prostate therapy was validated experimentally, reinforcing their utility as an effective treatment planning tool.

Burtnyk, Mathieu; Apoutou N'Djin, William; Kobelevskiy, Ilya; Bronskill, Michael; Chopra, Rajiv

2010-11-01

204

A case of definitive type 2 autoimmune pancreatitis diagnosed using endoscopic ultrasound-guided fine needle aspiration biopsy.  

PubMed

A 29-year-old man with ulcerative colitis presented to the hospital complaining of persistent back pain. Pancreatic enzymes and tumor markers were elevated; imaging showed diffuse narrowing of the main pancreatic duct associated with diffuse pancreatic enlargement. We therefore performed an endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) biopsy of the pancreas using a 19-gauge needle. Histopathology revealed interlobular fibrosis, neutrophil infiltration in the intralobular ducts and acini, and very few immunoglobulin G4-positive cells. The patient was diagnosed with type 2 autoimmune pancreatitis and started on oral steroids; subsequently, we observed an improvement in the pancreatic enlargement and duct narrowing. Histologically proven type 2 autoimmune pancreatitis is rare in Japan. PMID:25373380

Yano, Masaaki; Nishikawa, Masashi; Asai, Jun; Urabe, Takeshi; Ito, Hiroshi

2014-11-01

205

Histoacryl tissue adhesive in some types of retinal detachment surgery.  

PubMed Central

Preserved human scleral graft and histoacryl-blue tissue adhesive were used in four cases of retinal detachment surgery to obtain scleral buckling effect and to protect staphylomatous or necrotic scleral areas. The use of histoacryl produced a strong and resistant adhesion between the host and the preserved scleral patch. The postoperative inflammatory reaction was mild and disappeared within one week. PMID:987798

Regenbogen, L.; Romano, A.; Zuckerman, M.; Stein, R.

1976-01-01

206

valuation of the in vivo contrast using fast spin echo MRI sequences between tissues and thermal lesions in rabbit produced by high intensity focused ultrasound  

NASA Astrophysics Data System (ADS)

In this paper the goal was to measure the contrast to noise ratio (CNR) of fast spin echo (FSE) magnetic resonance imaging (MRI) sequences in detecting thermal lesions created by high intensity focused ultrasound (HIFU) in rabbit kidney, liver, heart, and brain and lamb pancreas. A spherically focused transducer was used which is navigated inside MRI by a custom made positioning device. A simple simulation model was developed which predicts the CNR for the two FSE MRI sequences. The maximum contrast measured with T1-W FSE ranges from 10 to 25. For all 5 tissues of interest if one uses TR between 400 and 500 ms the contrast is maximized. The T1, and T2 value of lesion depends strongly on the host tissue and is always lower than the host tissue. The greater the difference in T1 value, the greater the CNR. The simulated model for predicting the CNR was proven successful. The CNR measured with T2-W FSE varies between 12 and 15 for all 5 tissues. With T2-W FSE if one uses TE between 40 and 50 ms, the contrast is maximized.

Damianou, Christakis; Ioannides, Kleanthis; Hadjisavas, Venediktos; Milonas, Nikos; Couppis, Andreas; Iosif, Demitris

2010-03-01

207

Course Outline Course Medical Physics /BME 575: Diagnostic Ultrasound Physics  

E-print Network

1 Course Outline Course Medical Physics /BME 575: Diagnostic Ultrasound Physics Session Spring 2014 Acoustic properties of tissue 4 18th February Ultrasound Transducers 5 20th February Ultrasound Transducers 5 25th February Test 1: Chapters 1-4 27th February Ultrasound Transducers 5 4th March Ultrasound

Walker, Thad G.

208

Investigation of foreign objects in soft-tissue using a PE-CMOS ultrasound system: a preliminary comparative study  

Microsoft Academic Search

In this study, we have tested the ability of four imaging modalities to investigate foreign objects in soft tissue. We inserted wood, plastic, glass, and aluminum objects into a pork sample to simulate traumatized soft tissue. Each object was inserted into the skin, then passed through the fat tissue layer and penetrated into the muscle layer. We then took images

Chu-Chuan Liu; Shih-Chung Ben Lo; Matthew T. Freedman; Marvin E. Lasser; Bob Lasser; John Kula; Yue Joseph Wang; Tsung-I. Hsieh; Anita Sarcone

2006-01-01

209

The characteristic ultrasound features of specific types of ovarian pathology (review).  

PubMed

Characterizing ovarian masses enables patients with malignancy to be appropriately triaged for treatment by subspecialist gynecological oncologists, which has been shown to optimize care and improve survival. Furthermore, correctly classifying benign masses facilitates the selection of patients with ovarian pathology that may either not require intervention, or be suitable for minimal access surgery if intervention is required. However, predicting whether a mass is benign or malignant is not the only clinically relevant information that we need to know before deciding on appropriate treatment. Knowing the specific histology of a mass is becoming of increasing importance as management options become more tailored to the individual patient. For example predicting a mucinous borderline tumor gives the opportunity for fertility sparing surgery, and will highlight the need for further gastrointestinal assessment. For benign disease, predicting the presence of an endometrioma and possible deeply infiltrating endometriosis is important when considering both who should perform and the extent of surgery. An examiner's subjective assessment of the morphological and vascular features of a mass using ultrasonography has been shown to be highly effective for predicting whether a mass is benign or malignant. Many masses also have features that enable a reliable diagnosis of the specific pathology of a particular mass to be made. In this narrative review we aim to describe the typical morphological features seen on ultrasound of different adnexal masses and illustrate these by showing representative ultrasound images. PMID:25406094

Sayasneh, Ahmad; Ekechi, Christine; Ferrara, Laura; Kaijser, Jeroen; Stalder, Catriona; Sur, Shyamaly; Timmerman, Dirk; Bourne, Tom

2015-02-01

210

The characteristic ultrasound features of specific types of ovarian pathology (Review)  

PubMed Central

Characterizing ovarian masses enables patients with malignancy to be appropriately triaged for treatment by subspecialist gynecological oncologists, which has been shown to optimize care and improve survival. Furthermore, correctly classifying benign masses facilitates the selection of patients with ovarian pathology that may either not require intervention, or be suitable for minimal access surgery if intervention is required. However, predicting whether a mass is benign or malignant is not the only clinically relevant information that we need to know before deciding on appropriate treatment. Knowing the specific histology of a mass is becoming of increasing importance as management options become more tailored to the individual patient. For example predicting a mucinous borderline tumor gives the opportunity for fertility sparing surgery, and will highlight the need for further gastrointestinal assessment. For benign disease, predicting the presence of an endometrioma and possible deeply infiltrating endometriosis is important when considering both who should perform and the extent of surgery. An examiner’s subjective assessment of the morphological and vascular features of a mass using ultrasonography has been shown to be highly effective for predicting whether a mass is benign or malignant. Many masses also have features that enable a reliable diagnosis of the specific pathology of a particular mass to be made. In this narrative review we aim to describe the typical morphological features seen on ultrasound of different adnexal masses and illustrate these by showing representative ultrasound images. PMID:25406094

SAYASNEH, AHMAD; EKECHI, CHRISTINE; FERRARA, LAURA; KAIJSER, JEROEN; STALDER, CATRIONA; SUR, SHYAMALY; TIMMERMAN, DIRK; BOURNE, TOM

2015-01-01

211

Obstetrical Ultrasound  

MedlinePLUS

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

212

Scrotal Ultrasound  

MedlinePLUS

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

213

Ultrasound - Breast  

MedlinePLUS

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

214

Abdominal Ultrasound  

MedlinePLUS

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

215

Ultrasound -- Vascular  

MedlinePLUS

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

216

Topographical Control of Ocular Cell Types for Tissue Engineering  

PubMed Central

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 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. PMID:23744715

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

2014-01-01

217

Feasibility of using ultrasound contrast agents to increase the size of thermal lesions induced by non-focused transducers: in vitro demonstration in tissue mimicking phantom.  

PubMed

Miniature flat ultrasound transducers have shown to be effective for a large variety of thermal therapies, but the associated superficial heating implicates developing original strategies in order to extend therapeutic depth. The goal of the present paper is to use ultrasound contrast agents (UCA) to increase remote attenuation and heating. Theoretical simulations demonstrated that increasing attenuation from 0.27 to 0.8 Np/cm at 10 MHz beyond a distance of 18 mm from the transducer should result in longer thermal damages due to protein coagulation in a tissue mimicking phantom. Contrast agents (BR14, Bracco, Plan-les-Ouates, Switzerland) were embedded in thermo-sensitive gel and attenuations ranging from 0.27 to 1.33 Np/cm were measured at 10 MHz for concentrations of BR14 between 0 and 4.8%. Thermal damages were then induced in several gels, which had different layering configurations. Thermal damages, 12.8mm in length, were obtained in homogeneous gels. When mixing contrast agents at a concentration of 3.2% beyond a first 18 mm-thick layer of homogeneous gel, the thermal damages reached 21.5mm in length. This work demonstrated that contrast agents can be used for increasing attenuation remotely and extending therapeutic depth induced by a non-focused transducer. Additional work must be done in vivo in order to verify the remote-only distribution of bubbles and associated increase in attenuation. PMID:18796342

Lafon, Cyril; Murillo-Rincon, Adriana; Goldenstedt, Cédric; Chapelon, Jean Yves; Mithieux, François; Owen, Neil R; Cathignol, Dominique

2009-02-01

218

Combination of high-intensity focused ultrasound irradiation and hydroxyapatite nanoparticle injection to injure normal goat liver tissue in vivo without costal bone incision.  

PubMed

The aims of this study were to evaluate the in vivo safety of intravenous nano-hydroxyapatite (nano-HA), to explore how nano-HA might influence the effects of high-intensity focused ultrasound (HIFU) on normal liver tissue, and to investigate whether intravenous nano-HA could enhance HIFU for hepatocellular carcinoma ablation in a goat model. The present study, for the first time, indicated that the delivery of abundant nano-HA into the body over short periods of time could be assembled by the hepatic reticuloendothelial system, subsequently leading to a rapid rise of ultrasound-induced overheating, and ultimately resulting in enlargement of the coagulation necrotic area for ablated hepatocellular carcinoma in goats both in vivo and ex vivo. On the other hand, therapeutic doses of nano-HA were much lower than the lethal dose, and consequently presented transient and mild abnormalities of hepatic enzymes and renal function during the first 24 h after nano-HA injection. These results suggested that the combined application of nano-HA and HIFU is potentially a more effective alternative option compared to surgery for hepatocellular carcinoma local ablation in a safe and feasible manner. PMID:25366724

Liu, L; Xiao, Z; Xiao, Y; Wang, Z; Li, F; Li, M; Peng, X

2014-01-01

219

Gold nanoparticle targeted photoacoustic cavitation for potential deep tissue imaging and therapy  

PubMed Central

The laser generation of vapor bubbles around plasmonic nanoparticles can be enhanced through the application of an ultrasound field; a technique referred to as photoacoustic cavitation. The combination of light and ultrasound allows for bubble formation at lower laser fluence and peak negative ultrasound pressure than can be achieved using either modality alone. The growth and collapse of these bubbles leads to local mechanical disruption and acoustic emission, and can potentially be used to induce and monitor tissue therapy. Photoacoustic cavitation is investigated for a broad range of ultrasound pressures and nanoparticle concentrations for gold nanorods and nanospheres. The cavitation threshold fluences for both nanoparticle types are found to drastically reduce in the presence of an ultrasound field. The results indicate that photoacoustic cavitation can potentially be produced at depth in biological tissue without exceeding the safety limits for ultrasound or laser radiation at the tissue surface. PMID:23304648

Ju, Hengyi; Roy, Ronald A.; Murray, Todd W.

2012-01-01

220

Morphologic and Functional Changes in Nontumorous Liver Tissue After Radiofrequency Ablation in an In Vivo Model: Comparison of 18F-FDG PET\\/CT, MRI, Ultrasound, and CT  

Microsoft Academic Search

Rimlike contrast enhancement on morphologic imaging and increased tracer uptake on 18F-FDG PET in the periphery of the necrosis can hamper differentiation of residual tumor from re- generative tissue after radiofrequency ablation of liver lesions. ThisstudyusedMRI,CT,ultrasound,and 18F-FDGPET\\/CTtoas- sess the typical appearance of lesions in nontumorous animal liver tissue after radiofrequency ablation. Methods: Lesions were created by radiofrequency ablation of normal

Florian M. Vogt; Gerald Antoch; Patrick Veit; Lutz S. Freudenberg; Nina Blechschmid; Olaf Diersch; Andreas Bockisch; Hilmar Kuehl

221

Towards enabling ultrasound guidance in cervical cancer high-dose-rate brachytherapy  

NASA Astrophysics Data System (ADS)

MRI and Computed Tomography (CT) are used in image-based solutions for guiding High Dose Rate (HDR) brachytherapy treatment of cervical cancer. MRI is costly and CT exposes the patients to ionizing radiation. Ultrasound, on the other hand, is affordable and safe. The long-term goal of our work is to enable the use of multiparametric ultrasound imaging in image-guided HDR for cervical cancer. In this paper, we report the development of enabling technology for ultrasound guidance and tissue typing. We report a system to obtain the 3D freehand transabdominal ultrasound RF signals and B-mode images of the uterus, and a method for registration of ultrasound to MRI. MRI and 3D ultrasound images of the female pelvis were registered by contouring the uterus in the two modalities, creating a surface model, followed by rigid and B-spline deformable registration. The resulting transformation was used to map the location of the tumor from the T2-weighted MRI to ultrasound images and to determine cancerous and normal areas in ultrasound. B-mode images show a contrast for cancer vs. normal tissue. Our study shows the potential and the challenges of ultrasound imaging in guiding cervical cancer treatments.

Wong, Adrian; Sojoudia, Samira; Gaudet, Marc; Yap, Wan Wan; Chang, Silvia D.; Abolmaesumi, Purang; Aquino-Parsons, Christina; Moradi, Mehdi

2014-03-01

222

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. PMID:16934858

O'Brien, William D.

2007-01-01

223

Ultrasound-biophysics mechanisms.  

PubMed

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 non-thermal 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. PMID:16934858

O'Brien, William D

2007-01-01

224

In-vivo synthetic aperture flow imaging in medical ultrasound  

Microsoft Academic Search

A new method for acquiring flow images using synthetic aperture techniques in medical ultrasound is presented. The new approach makes it possible to have a continuous acquisition of flow data throughout the whole image simultaneously, and this can significantly improve blood velocity estimation. Any type of filter can be used for discrimination between tissue and blood flow without initialization, and

Svetoslav Ivanov Nikolov; Jmgen Arendt Jensen

2003-01-01

225

Intravascular ultrasound chirp imaging  

NASA Astrophysics Data System (ADS)

We demonstrate the feasibility of intravascular ultrasound (IVUS) chirp imaging as well as chirp reversal ultrasound contrast imaging at intravascular ultrasound frequency. Chirp excitations were emitted with a 34 MHz single crystal intravascular transducer and compared to conventional Gaussian-shaped pulses of equal acoustic pressure. The signal to noise ratio of the chirp images was increased by up to 9 dB relative to the conventional images. Imaging of contrast microbubbles was implemented by chirp reversal, achieving a contrast to tissue ratio of 12 dB. The method shows potential for intravascular imaging of structures in and beyond coronary atherosclerotic plaques including vasa vasorum.

Maresca, D.; Jansen, K.; Renaud, G.; van Soest, G.; Li, X.; Zhou, Q.; de Jong, N.; Shung, K. K.; van der Steen, A. F. W.

2012-01-01

226

Markov models of specular and diffuse scattering in restoration of medical ultrasound images  

Microsoft Academic Search

Observed medical ultrasound images are degraded representations of the true tissue reflectance. The specular reflections at boundaries between regions of different tissue types are blurred, and the diffuse scattering within such regions also contains speckle. This reduces the diagnostic value of such images. In order to remove both blur and speckle, the authors develop a maximum a posteriori deconvolution algorithm

J. H. Hokland; Patrick A. Kelly

1996-01-01

227

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

Code of Federal Regulations, 2011 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...

2011-04-01

228

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

...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....

2014-04-01

229

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

230

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

Code of Federal Regulations, 2012 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

231

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

Code of Federal Regulations, 2013 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...

2013-04-01

232

Prostate tissue characterization/classification in 144 patient population using wavelet and higher order spectra features from transrectal ultrasound images.  

PubMed

In this work, we have proposed an on-line computer-aided diagnostic system called "UroImage" that classifies a Transrectal Ultrasound (TRUS) image into cancerous or non-cancerous with the help of non-linear Higher Order Spectra (HOS) features and Discrete Wavelet Transform (DWT) coefficients. The UroImage system consists of an on-line system where five significant features (one DWT-based feature and four HOS-based features) are extracted from the test image. These on-line features are transformed by the classifier parameters obtained using the training dataset to determine the class. We trained and tested six classifiers. The dataset used for evaluation had 144 TRUS images which were split into training and testing sets. Three-fold and ten-fold cross-validation protocols were adopted for training and estimating the accuracy of the classifiers. The ground truth used for training was obtained using the biopsy results. Among the six classifiers, using 10-fold cross-validation technique, Support Vector Machine and Fuzzy Sugeno classifiers presented the best classification accuracy of 97.9% with equally high values for sensitivity, specificity and positive predictive value. Our proposed automated system, which achieved more than 95% values for all the performance measures, can be an adjunct tool to provide an initial diagnosis for the identification of patients with prostate cancer. The technique, however, is limited by the limitations of 2D ultrasound guided biopsy, and we intend to improve our technique by using 3D TRUS images in the future. PMID:23745787

Pareek, Gyan; Acharya, U Rajendra; Sree, S Vinitha; Swapna, G; Yantri, Ratna; Martis, Roshan Joy; Saba, Luca; Krishnamurthi, Ganapathy; Mallarini, Giorgio; El-Baz, Ayman; Al Ekish, Shadi; Beland, Michael; Suri, Jasjit S

2013-12-01

233

An Endothelial Storage Granule for Tissue-Type Plasminogen Activator  

Microsoft Academic Search

In previous studies we have shown that, after stimulation by a receptor ligand such as thrombin, tis- sue-type plasminogen activator (tPA) and von Wille- brand factor (vWf) will be acutely released from human umbilical vein endothelial cells (HUVEC). However, the mechanisms involved in the secretion of these two pro- teins differ in some respects, suggesting that the two pro- teins

J. J. Emeis; Y. van den Eijnden-Schrauwen; C. M. van den Hoogen; W. de Priester; A. Westmuckett; F. Lupu

1997-01-01

234

Ultrasound mediated delivery of drugs and genes to solid tumors  

PubMed Central

It has long been shown that therapeutic ultrasound can be used effectively to ablate solid tumors, and a variety of cancers are presently being treated in the clinic using these types of ultrasound exposures. There is, however, an ever-increasing body of preclinical literature that demonstrates how ultrasound energy can also be used non-destructively for increasing the efficacy of drugs and genes for improving cancer treatment. In this review, a summary of the most important ultrasound mechanisms will be given with a detailed description of how each one can be employed for a variety of applications. This includes the manner by which acoustic energy deposition can be used to create changes in tissue permeability for enhancing the delivery of conventional agents, as well as for deploying and activating drugs and genes via specially tailored vehicles and formulations. PMID:18474406

Frenkel, Victor

2008-01-01

235

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

236

An In Vivo Study of the Effects on Serum Glucose, Amylase and Histopathology of the Feline Pancreatic Tissue Treated by Focused Ultrasound  

PubMed Central

Pancreatic cancer is one of the most malignant neoplasms originating in the digestive system. Focused ultrasound (FUS) treatment instead of the surgery operation has been used to treat Pancreatic cancer noninvasively in clinical trials. The endocrine and exocrine glands in pancreas provide the two unique functions for a person to be healthy. It is critically important to find out if the FUS treatment can still keep the normal functions of the two glands. The goal of this study is to examine and analyze changes in histopathology and serum glucose and amylase levels of the targeted in-vivo felines after the FUS treatment. Various percentage volumes of pancreas of felines were insonified. The FUS treatment (7.5 MHz of central frequency; 5 W of acoustical power; transducer f-number ?=?0.33; 6 s insonification time per point) effectively generated coagulative necrosis at the insonified site while leaving tissue outside the insonified site intact. It was also observed that all felines endured well with the FUS treatment; changes introduced to pancreatic tissue after up to 50% of a pancreas by volume was insonified by the FUS procedure did not affect its normal endocrine and exocrine functions. PMID:24558434

Li, Chongyan; Wang, Zhibiao; Wu, Junru; Bai, Jin; Li, Faqi

2014-01-01

237

2-D PSTD Simulation of the time-reversed ultrasound-encoded deep-tissue imaging technique  

PubMed Central

We present a robust simulation technique to model the time-reversed ultrasonically encoded (TRUE) technique for deep-tissue imaging. The pseudospectral time-domain (PSTD) algorithm is employed to rigorously model the electromagnetic wave interaction of light propagating through a macroscopic scattering medium. Based upon numerical solutions of Maxwell’s equations, the amplitude and phase are accurately accounted for to analyze factors that affect the TRUE propagation of light through scattering media. More generally, we demonstrate the feasibility of modeling light propagation through a virtual tissue model of macroscopic dimensions with numerical solutions of Maxwell’s equations. PMID:24688821

Tseng, Snow H.; Ting, Wei-Lun; Wang, Shiang-Jiu

2014-01-01

238

Despeckling of medical ultrasound images  

Microsoft Academic Search

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

Oleg V. Michailovich; Allen Tannenbaum

2006-01-01

239

Collagen type II enhances chondrogenesis in adipose tissue-derived stem cells by affecting cell shape  

Microsoft Academic Search

Ideally, biomaterials have inductive properties, favoring specific lineage differentiation. For chondrogenic induction, these properties have been attributed to collagen type II. However, the underlying mechanisms are largely unknown. This study aimed to investigate whether collagen type II favors chondrogenic induction by affecting cell shape through ?1 integrins and Rho A\\/Rock signaling. For this purpose, adipose tissue–derived stem cells (ASCs) were

ZuFu Lu; Behrouz Zandieh Doulabi; ChunLing Huang; Ruud A. Bank; Marco N. Helder

2010-01-01

240

Atherosclerotic plaque tissue characterization in 2D ultrasound longitudinal carotid scans for automated classification: a paradigm for stroke risk assessment.  

PubMed

In the case of carotid atherosclerosis, to avoid unnecessary surgeries in asymptomatic patients, it is necessary to develop a technique to effectively differentiate symptomatic and asymptomatic plaques. In this paper, we have presented a data mining framework that characterizes the textural differences in these two classes using several grayscale features based on a novel combination of trace transform and fuzzy texture. The features extracted from the delineated plaque regions in B-mode ultrasound images were used to train several classifiers in order to prepare them for classification of new test plaques. Our CAD system was evaluated using two different databases consisting of 146 (44 symptomatic to 102 asymptomatic) and 346 (196 symptomatic and 150 asymptomatic) images. Both these databases differ in the way the ground truth was determined. We obtained classification accuracies of 93.1 and 85.3 %, respectively. The techniques are low cost, easily implementable, objective, and non-invasive. For more objective analysis, we have also developed novel integrated indices using a combination of significant features. PMID:23292291

Acharya, U Rajendra; Mookiah, Muthu Rama Krishnan; Vinitha Sree, S; Afonso, David; Sanches, Joao; Shafique, Shoaib; Nicolaides, Andrew; Pedro, L M; Fernandes E Fernandes, J; Suri, Jasjit S

2013-05-01

241

Simulation and validation of arterial ultrasound imaging and blood flow.  

PubMed

We reviewed the simulation and validation of arterial ultrasound imaging and blood flow assessment. The physical process of ultrasound imaging and measurement is complex, especially in disease. Simulation of physiological flow in a phantom with tissue equivalence of soft tissue, vessel wall and blood is now achievable. Outstanding issues are concerned with production of anatomical models, simulation of arterial disease, refinement of blood mimics to account for non-Newtonian behavior and validation of velocity measurements against an independent technique such as particle image velocimetry. String and belt phantoms offer simplicity of design, especially for evaluation of velocity estimators, and have a role as portable test objects. Electronic injection and vibrating test objects produce nonphysiologic Doppler signals, and their role is limited. Computational models of the ultrasound imaging and measurement process offer considerable flexibility in their ability to alter multiple parameters of both the propagation medium and ultrasound instrument. For these models, outstanding issues are concerned with the inclusion of different tissue types, multilayer arteries, inhomogeneous tissues and diseased tissues. PMID:18329162

Hoskins, Peter R

2008-05-01

242

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

243

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

PubMed

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 degrees 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 x 3 x 10 mm for the control point, and a temperature uncertainty of approximately 1 degrees 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. PMID:17473359

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

2007-05-21

244

Improved cardiac motion detection from ultrasound images using TDIOF: a combined B-mode/ tissue Doppler approach  

NASA Astrophysics Data System (ADS)

Quantitative motion analysis of echocardiographic images helps clinicians with the diagnosis and therapy of patients suffering from cardiac disease. Quantitative analysis is usually based on TDI (Tissue Doppler Imaging) or speckle tracking. These methods are based on two independent techniques - the Doppler Effect and image registration, respectively. In order to increase the accuracy of the speckle tracking technique and cope with the angle dependency of TDI, herein, a combined approach dubbed TDIOF (Tissue Doppler Imaging Optical Flow) is proposed. TDIOF is formulated based on the combination of B-mode and Doppler energy terms in an optical flow framework and minimized using algebraic equations. In this paper, we report on validations with simulated, physical cardiac phantom, and in-vivo patient data. It is shown that the additional Doppler term is able to increase the accuracy of speckle tracking, the basis for several commercially available echocardiography analysis techniques.

Tavakoli, Vahid; Stoddard, Marcus F.; Amini, Amir A.

2013-03-01

245

Assessment of ultrasound-assisted extraction as sample pre-treatment for the measurement of lead isotope ratios in marine biological tissues by multicollector inductively coupled plasma-mass spectrometry  

NASA Astrophysics Data System (ADS)

In this work, ultrasound-assisted extraction (UAE) was evaluated as a sample preparation procedure for lead isotope ratio measurements in marine biological tissues by multicollector inductively coupled plasma-mass spectrometry. 20 mg of marine biological tissue and 1 mL of acid extractant were sonicated for 3 min at 60% ultrasound amplitude. Matrix separation was performed in the supernatant using a chromatographic exchange resin (Sr-Spec™). Total elimination of organic matter was achieved during the separation step. Microwave-assisted digestion and dry-ashing were used for comparative purposes. No significant differences were found in lead isotope ratios at 95% of confidence level. UAE emerges as an advantageous alternative to classical methods for sample preparation owing to its simplicity and rapidity ( i.e. operation steps were reduced), low reagent consumption and low contamination risks.

Costas-Rodríguez, M.; Lavilla, Isela; Bendicho, Carlos

2011-06-01

246

Thyroid ultrasound  

PubMed Central

Thyroid ultrasonography has established itself as a popular and useful tool in the evaluation and management of thyroid disorders. Advanced ultrasound techniques in thyroid imaging have not only fascinated the radiologists but also attracted the surgeons and endocrinologists who are using these techniques in their daily clinical and operative practice. This review provides an overview of indications for ultrasound in various thyroid diseases, describes characteristic ultrasound findings in these diseases, and illustrates major diagnostic pitfalls of thyroid ultrasound. PMID:23776892

Chaudhary, Vikas; Bano, Shahina

2013-01-01

247

Studies of Bone Density, Quantitative Ultrasound, and Vertebral Fractures in Relation to Collagen Type I Alpha 1 Alleles in Elderly Women  

Microsoft Academic Search

Previous studies have demonstrated that an Sp1 binding site polymorphism in the collagen type I gene (COLIA1) is related to reduced bone mineral density (BMD) and osteoporotic fractures in certain populations, particularly in the elderly. We have examined the relationship among these COLIA1 Sp1 alleles, BMD, quantitative ultrasound properties of bone, and fractures in a population-based cohort of elderly women

R. U. Ashford; M. Luchetti; E. V. McCloskey; R. L. Gray; K. C. Pande; A. Dey; K. Kayan; S. H. Ralston; J. A. Kanis

2001-01-01

248

Type-1 pericytes participate in fibrous tissue deposition in aged skeletal muscle  

PubMed Central

In older adults, changes in skeletal muscle composition are associated with increased fibrosis, loss of mass, and decreased force, which can lead to dependency, morbidity, and mortality. Understanding the biological mechanisms responsible is essential to sustaining and improving their quality of life. Compared with young mice, aged mice take longer to recover from muscle injury; their tissue fibrosis is more extensive, and regenerated myofibers are smaller. Strong evidence indicates that cells called pericytes, embedded in the basement membrane of capillaries, contribute to the satellite-cell pool and muscle growth. In addition to their role in skeletal muscle repair, after tissue damage, they detach from capillaries and migrate to the interstitial space to participate in fibrosis formation. Here we distinguish two bona fide pericyte subtypes in the skeletal muscle interstitium, type-1 (Nestin-GFP?/NG2-DsRed+) and type-2 (Nestin-GFP+/NG2-DsRed+), and characterize their heretofore unknown specific roles in the aging environment. Our in vitro results show that type-1 and type-2 pericytes are either fibrogenic or myogenic, respectively. Transplantation studies in young animals indicate that type-2 pericytes are myogenic, while type-1 pericytes remain in the interstitial space. In older mice, however, the muscular regenerative capacity of type-2 pericytes is limited, and type-1 pericytes produce collagen, contributing to fibrous tissue deposition. We conclude that in injured muscles from aging mice, the pericytes involved in skeletal muscle repair differ from those associated with scar formation. PMID:24067916

Birbrair, Alexander; Zhang, Tan; Wang, Zhong-Min; Messi, Maria Laura; Mintz, Akiva

2013-01-01

249

Effects of low-power LED and therapeutic ultrasound in the tissue healing and inflammation in a tendinitis experimental model in rats.  

PubMed

This work evaluated the anti-inflammatory response of low-power light-emitting diode (LED) and ultrasound (US) therapies and the quality and rapidness of tendon repair in an experimental model of tendinitis, employing histomorphometry and Raman spectroscopy. Tendinitis was induced by collagenase into the right tendon of 35 male Wistar rats with an average weight of 230 g. The animals were randomly separated into seven groups of five animals each: tendinitis without treatment-control (TD7 and TD14, where 1 and 2 indicated sacrifice on the 7th and 14th day, respectively), tendinitis submitted to US therapy (US7 and US14) and tendinitis submitted to LED therapy (LED7 and LED14). Contralateral tendons of the TD group at the 14th day were used as the healthy group (H). US treatment was applied in pulsed mode at 10 %, 1 MHz frequency, 0.5 W/cm(2), 120 s. LED therapy parameters were 4 J/cm(2), 120 s, daily dose at the same time and same point. Sacrifice was performed on the 7th or 14th day. Histomorphometric analysis showed lower number of fibroblasts on the 14th day of therapy for the US-treated group, compared to the TD and LED, indicating lower tissue inflammation. Raman showed that the LED group had an increase in the amount of collagen I and III from the 7th to the 14th day, which would indicate more organized fibers and a better quality of the healing, and US showed lower collagen I synthesis in the 14th day compared to H, indicating a lower tissue reorganization. PMID:23660737

Moura Júnior, Manoel de Jesus; Arisawa, Emilia Ângela Loschiavo; Martin, Airton Abrahão; de Carvalho, Janderson Pereira; da Silva, José Mário Nunes; Silva, José Figueiredo; Silveira, Landulfo

2014-01-01

250

The future perspectives in transrectal prostate ultrasound guided biopsy  

PubMed Central

Prostate cancer is one of the most common neoplasms in men. Transrectal ultrasound (TRUS)-guided systematic biopsy has a crucial role in the diagnosis of prostate cancer. However, it shows limited value with gray-scale ultrasound alone because only a small number of malignancies are visible on TRUS. Recently, new emerging technologies in TRUS-guided prostate biopsy were introduced and showed high potential in the diagnosis of prostate cancer. High echogenicity of ultrasound contrast agent reflect the increased status of angiogenesis in tumor. Molecular imaging for targeting specific biomarker can be also used using ultrasound contrast agent for detecting angiogenesis or surface biomarker of prostate cancer. The combination of TRUS-guided prostate biopsy and ultrasound contrast agents can increase the accuracy of prostate cancer diagnosis. Elastography is an emerging ultrasound technique that can provide the information regarding tissue elasticity and stiffness. Tumors are usually stiffer than the surrounding soft tissue. In two types of elastography techniques, shearwave elastography has many potential in that it can provide quantitative information on tissue elasticity. Multiparametric magnetic resonance imaging (MRI) from high resolution morphologic and functional magnetic resonance (MR) technique enables to detect more prostate cancers. The combination of functional techniques including apparent diffusion coefficient map from diffusion weighted imaging, dynamic contrast enhanced MR and MR spectroscopy are helpful in the localization of the prostate cancer. MR-ultrasound (US) fusion image can enhance the advantages of both two modalities. With MR-US fusion image, targeted biopsy of suspicious areas on MRI is possible and fusion image guided biopsy can provide improved detection rate. In conclusion, with recent advances in multiparametric-MRI, and introduction of new US techniques such as contrast-enhanced US and elastography, TRUS-guided biopsy may evolve toward targeted biopsies rather than systematic biopsy for getting information reflecting the exact status of the prostate. PMID:25599070

Hwang, Sung II; Lee, Hak Jong

2014-01-01

251

Controlling collagen fiber microstructure in three-dimensional hydrogels using ultrasound  

PubMed Central

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

2013-01-01

252

Medical ultrasound with microbubbles  

Microsoft Academic Search

In the medical ultrasound applications, microbubbles are closely tied to the diagnostic\\/therapeutic uses. For diagnostic applications, their sound scattering properties yield improved imaging, when the microbubbles are used as contrast agents. The harmonics and subharmonics responses from the bubbles assist in distinguishing the acoustic scattering of blood from that of the surrounding tissue. The therapeutic use of microbubbles has recently

Yoichiro Matsumoto; John S. Allen; Shin Yoshizawa; Teiichiro Ikeda; Yukio Kaneko

2005-01-01

253

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

NASA Astrophysics Data System (ADS)

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

Arvanitis, Costas D.; Livingstone, Margaret S.; McDannold, Nathan

2013-07-01

254

Combined Ultrasound and MR Imaging to Guide Focused Ultrasound Therapies in the Brain  

PubMed Central

Purpose Several emerging therapies with potential for use in the brain harness effects produced by acoustic cavitation – the interaction between ultrasound and microbubbles either generated during sonication or introduced into the vasculature. Systems developed for transcranial MRI-guided focused ultrasound (MRgFUS) thermal ablation can enable their clinical translation, but methods for real-time monitoring and control are currently lacking. Acoustic emissions produced during sonication can provide information about the location, strength, and type of the microbubble oscillations within the ultrasound field, and they can be mapped in real-time using passive imaging approaches. Here, we tested whether such mapping can be achieved transcranially within a clinical brain MRgFUS system. Materials and Methods We integrated an ultrasound imaging array into the hemisphere transducer of the MRgFUS device. Passive cavitation maps were obtained during sonications combined with a circulating microbubble agent at 20 targets in the cingulate cortex in three macaques. The maps were compared with MRI-evident tissue effects. Results The system successfully mapped microbubble activity during both stable and inertial cavitation, which was correlated with MRI-evident transient blood-brain barrier disruption and vascular damage, respectively. The location of this activity was coincident with the resulting tissue changes within the expected resolution limits of the system. Conclusion While preliminary, these data clearly demonstrate, for the first time, that is possible to construct maps of stable and inertial cavitation transcranially, in a large animal model, and under clinically relevant conditions. Further, these results suggest that this hybrid ultrasound/MRI approach can provide comprehensive guidance for targeted drug delivery via blood-brain barrier disruption and other emerging ultrasound treatments, facilitating their clinical translation. We anticipate it will also prove to be an important research tool that will further the development of a broad range of microbubble-enhanced therapies. PMID:23788054

Arvanitis, Costas D.; Livingstone, Margaret S.; McDannold, Nathan

2013-01-01

255

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

256

Tissue preconditioning may explain concentric lesions in Baló's type of multiple sclerosis.  

PubMed

Lesions of Baló's concentric sclerosis are characterized by alternating layers of myelinated and demyelinated tissue. The reason for concentric demyelination in this variant of multiple sclerosis is unclear. In the present study we investigated the immunopathology in autopsy tissue of 14 patients with acute multiple sclerosis or fulminant exacerbations of chronic multiple sclerosis with Baló-type lesions in the CNS, focusing on the patterns of tissue injury in actively demyelinating lesions. We found that all active concentric lesions followed a pattern of demyelination that bears resemblances to hypoxia-like tissue injury. This was associated with high expression of inducible nitric oxide synthase in macrophages and microglia. At the edge of active lesions and, less consistently, in the outermost layer of preserved myelin, proteins involved in tissue preconditioning, such as hypoxia-inducible factor 1alpha and heat-shock protein 70, were expressed mainly in oligodendrocytes and to a lesser degree also in astrocytes and macrophages. Due to their neuroprotective effects, the rim of periplaque tissue, where these proteins are expressed, may be resistant to further damage in an expanding lesion and may therefore remain as a layer of preserved myelinated tissue. PMID:15774507

Stadelmann, Christine; Ludwin, Sam; Tabira, Takeshi; Guseo, Andras; Lucchinetti, Claudia F; Leel-Ossy, Lorant; Ordinario, Artemio T; Brück, Wolfgang; Lassmann, Hans

2005-05-01

257

Using data fusion to characterize breast tissue  

NASA Astrophysics Data System (ADS)

New ultrasound data, obtained with a circular experimental scanner, are compared with data obtained with standard X-ray CT. Ultrasound data obtained by scanning fixed breast tissue were used to generate images of sound speed and reflectivity. The ultrasound images exhibit approximately 1 mm resolution and about 20 dB of dynamic range. All data were obtained in a circular geometry. X-ray CT scans were used to generate X-ray images corresponding to the same 'slices' obtained with the ultrasound scanner. The good match of sensitivity, resolution and angular coverage between the ultrasound and X-ray data makes possible a direct comparison of the three types of images. We present the results of such a comparison for an excised breast fixed in formalin. The results are presented visually using various types of data fusion. A general correspondence between the sound speed, reflectivity and X-ray morphologies is found. The degree to which data fusion can help characterize tissue is assessed by examining the quantitative correlations between the ultrasound and X-ray images.

Duric, Nebojsa; Littrup, Peter J.; Leach, Richard, Jr.; Azevedo, Steve G.; Candy, James V.; Moore, Thomas; Chambers, David H.; Mast, Jeffrey E.; Holsapple, Earle

2002-04-01

258

Using Data Fusion to Characterize Breast Tissue  

SciTech Connect

New ultrasound data, obtained with a circular experimental scanner, are compared with data obtained with standard X-ray CT. Ultrasound data obtained by scanning fixed breast tissue were used to generate images of sound speed and reflectivity. The ultrasound images exhibit approximately 1 mm resolution and about 20 dB of dynamic range. All data were obtained in a circular geometry. X-ray CT scans were used to generate X-ray images corresponding to the same 'slices' obtained with the ultrasound scanner. The good match of sensitivity, resolution and angular coverage between the ultrasound and X-ray data makes possible a direct comparison of the three types of images. We present the results of such a comparison for an excised breast fixed in formalin. The results are presented visually using various types of data fusion. A general correspondence between the sound speed, reflectivity and X-ray morphologies is found. The degree to which data fusion can help characterize tissue is assessed by examining the quantitative correlations between the ultrasound and X-ray images.

Littrup, P; Duric, N; Leach, R R; Azevedo, S G; Candy, J V; Moore, T; Chambers, D H; Mast, J E; Johnson, S A; Holsapple, E

2002-01-23

259

Posttranslational Modifications in Type I Collagen from Different Tissues Extracted from Wild Type and Prolyl 3-Hydroxylase 1 Null Mice*  

PubMed Central

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

2013-01-01

260

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

2013-08-23

261

Connective Tissue Reflex Massage for Type 2 Diabetic Patients with Peripheral Arterial Disease: Randomized Controlled Trial  

Microsoft Academic Search

The objective of this study was to evaluate the efficacy of connective tissue massage to improve blood circulation and intermittent claudication symptoms in type 2 diabetic patients. A ran- domized, placebo-controlled trial was undertaken. Ninety-eight type 2 diabetes patients with stage I or II-a peripheral arterial disease (PAD) (Leriche-Fontaine classification) were random- ly assigned to a massage group or to

Adelaida Maria Castro-Sanchez; Carmen Moreno-Lorenzo; Guillermo A. Mataran-Penarrocha; Belen Feriche-Fernandez-Castanys; Genoveva Granados-Gamez; JoseManuel Quesada-Rubio

2009-01-01

262

Tissue-Type Plasminogen Activator and Its Inhibitor in Rat Aorta Effect of Endotoxin  

Microsoft Academic Search

Plasminogen activator (PA) and PA inhibitor (PAI) antigen, activity, and mRNA were analyzed in the three layers of rat aorta, and the effect of endotoxin on PA and PAI was studied. All PA activity in aorta was identified as tissue-type PA (TPA) activity; no urokinase-type PA was detected. In the tunica adventitia TPA activity, TPA antigen, and TPA mRNA were

T. Padro; P. H. A. Quax; P. Roholl; J. H. Verheijen; J. J. Emeis

263

Comparison of the effects of pitavastatin versus pravastatin on coronary artery plaque phenotype assessed by tissue characterization using serial virtual histology intravascular ultrasound.  

PubMed

Thin-cap fibroatheroma (TCFA) is the most common type of vulnerable plaque and is the precursor of plaque rupture. However, rupture of a TCFA is not the only mechanism underlying thrombus formation or acute coronary syndrome. Although statin therapy changes the composition of coronary artery plaques, the effects of statins, particularly different types of statins, on plaque phenotype have not been fully examined. This study compared the effects of pitavastatin versus pravastatin on coronary artery plaque phenotype assessed by virtual histology (VH) intravascular ultrasound (IVUS) in patients with angina pectoris (AP). Coronary atherosclerosis in nonculprit lesions was evaluated using VH-IVUS at baseline and 8 months after statin therapy; analyzable IVUS data were obtained from 83 patients with stable AP (39 patients treated with pitavastatin and 44 with pravastatin) and 36 patients with unstable AP (19 patients treated with pitavastatin and 17 with pravastatin). Pitavastatin had a strong effect on reducing pathologic intimal thickening (PIT), especially in patients with unstable AP, but had no impact on VH-TCFA or fibroatheroma (FA). By contrast, pravastatin had weak effects on reducing PIT, VH-TCFA, or FA. Increases in the number of calcified plaques were observed for both statins. In conclusion, pitavastatin and pravastatin changed coronary artery plaque phenotype as assessed by VH-IVUS in patients with AP. However, the effects of these statins on coronary artery plaque phenotype were different. PMID:24337500

Nozue, Tsuyoshi; Yamamoto, Shingo; Tohyama, Shinichi; Fukui, Kazuki; Umezawa, Shigeo; Onishi, Yuko; Kunishima, Tomoyuki; Sato, Akira; Nozato, Toshihiro; Miyake, Shogo; Takeyama, Youichi; Morino, Yoshihiro; Yamauchi, Takao; Muramatsu, Toshiya; Hibi, Kiyoshi; Terashima, Mitsuyasu; Michishita, Ichiro

2015-01-01

264

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. PMID:22866226

Powers, Jeff; Kremkau, Frederick

2011-01-01

265

Modeling of a Type II Photofrin-mediated Photodynamic Therapy Process in a Heterogeneous Tissue Phantom  

Microsoft Academic Search

We present a quantitative framework to model a Type II photodynamic therapy (PDT) process in the time domain in which a set of rate equations are solved to describe molecular reactions. Calculation of steady-state light distributions using a Monte Carlo method in a heterogeneous tissue phantom model demonstrates that the photon density differs signifi- cantly in a superficial tumor of

Xin-Hua Hu; Yuanming Feng; Jun Q. Lu; Ron R. Allison; Rosa E. Cuenca; Gordon H. Downie; Claudio H. Sibata

2005-01-01

266

Metabolic factors, adipose tissue, and plasminogen activator inhibitor-1 levels in Type 2 diabetes  

Technology Transfer Automated Retrieval System (TEKTRAN)

Plasminogen activator inhibitor-1 (PAI-1) production by adipose tissue is increased in obesity, and its circulating levels are high in type 2 diabetes. PAI-1 increases cardiovascular risk by favoring clot stability, interfering with vascular remodeling, or both. We investigated in obese diabetic per...

267

Distribution of laminin, fibronectin, and interstitial collagen type III in soft tissue tumours  

Microsoft Academic Search

The distributions of laminin, fibronectin, and interstitial collagen type III have been investigated in a series of 60 soft tissue tumours by immunochemistry. Positive laminin staining was seen in sites predicted by the distribution of ultrastructurally visible basal lamina. Pericellular laminin was present in all benign tumours of Schwann cell and smooth muscle origin examined, in the two malignant Schwannomas

A J dArdenne; P Kirkpatrick; B C Sykes

1984-01-01

268

A texture-based methodology for identifying tissue type in magnetic resonance images  

Microsoft Academic Search

We propose a methodology for discriminating between various types of normal and diseased brain tissue in medical images that utilizes vector quantization (VQ), an image compression technique, to extract discriminative texture features. Rather than focusing on images of the entire brain, we direct our attention to extracting local descriptors for individual regions of interest (ROIs) as determined by domain experts.

Michael Barnathan; Jingjing Zhang; Erickson Miranda; Vasileios Megalooikonomou; Scott Faro; Harvey Hensley; Luis Del Valle; Kamel Khalili; Jennifer Gordon; Feroze B. Mohamed

2008-01-01

269

Doppler ultrasound findings correlate with tissue vascularity and inflammation in surgical pathology specimens from patients with small intestinal Crohn’s disease  

PubMed Central

Background Crohn’s disease (CD) is routinely evaluated using clinical symptoms, laboratory variables, and the CD activity index (CDAI). However, clinical parameters are often nonspecific and do not precisely reflect the actual activity of CD small-intestinal lesions. The purposes of this prospective study were to compare color Doppler ultrasound (US) findings with histological findings from surgically resected specimens and confirm the hypothesis that color Doppler US can distinguish tissue inflammation and fibrosis. Methods Among 1764 consecutive patients who underwent color Doppler US examinations, 10 patients with CD (12 small-intestinal CD lesions) who underwent US examinations before elective small-intestine resection were evaluated in the present study. Areas of thickened intestinal walls were evaluated in terms of blood flow using color Doppler US imaging. The blood flow was semiquantitatively classified as “hyper-flow” and “hypo-flow” according to the Limberg score. Resected lesions were macroscopically and histopathologically processed. Inflammatory cell infiltration, fibrosis and vascularity were evaluated by myeloperoxidase (granulocytes), CD163 (macrophages), CD79a (B cells), CD3 (T cells), Masson’s trichrome (fibrosis), and factor VIII staining (vascular walls). All histopathological images were entered into virtual slide equipment and quantified using a quantitative microscopy integrated system (TissueMorph™). Results There were no significant differences in disease features or laboratory findings between “hypo-flow” lesions (n?=?4) and “hyper-flow” lesions (n?=?8). Histopathologically, “hyper-flow” lesions showed significantly greater bowel wall vascularity (factor VIII) (p?=?0.047) and inflammatory cell infiltration, including CD163 macrophages (p?=?0.008), CD3 T cells, and CD79a B cells (p?=?0.043), than did “hypo-flow” lesions. There was no apparent association between the blood flow and CDAI. Conclusions In this study, active CD lesions were macroscopically visible in surgical specimens of patients with increased blood flow on preoperative color Doppler US imaging. Additionally, these CD lesions exhibited significantly greater vascularity and numbers of inflammatory leukocytes microscopically. Color Doppler US may predict tissue inflammation and fibrosis in small-intenstinal CD lesions. PMID:24927748

2014-01-01

270

Allelic imbalance of tissue-type plasminogen activator (t-PA) gene expression in human brain tissue.  

PubMed

We have identified a single-nucleotide polymorphism (SNP) in the t-PA enhancer (-7351C>T), which is associated with endothelial t-PA release in vivo. In vitro studies demonstrated that this SNP is functional at the level of transcription. In the brain, t-PA has been implicated in both physiologic and pathophysiologic processes. The aim of the present study was to examine the effect of the t-PA -7351C>T SNP on t-PA gene expression in human brain tissue. Allelic mRNA expression was measured in heterozygous post-mortem brain tissues using quantitative TaqMan genotyping assay. Protein-DNA interactions were assessed using electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP). Significantly higher levels of t-PA mRNA were generated from chromosomes that harboured the wild-type -7351C allele, as compared to those generated from the mutant T allele (for the hippocampus, C to T allelic ratio of ~1.3, p=0.010, n=12; and for the cortex, C to T allelic ratio of ~1.2, p=0.017, n=12). EMSA showed reduced neuronal and astrocytic nuclear protein binding affinity to the T allele, and identified Sp1 and Sp3 as the major transcription factors that bound to the -7351 site. ChIP analyses confirmed that Sp1 recognises this site in intact cells. In conclusion, the t-PA -7351C>T SNP affects t-PA gene expression in human brain tissue. This finding might have clinical implications for neurological conditions associated with enhanced t-PA levels, such as in the acute phase of cerebral ischaemia, and also for stroke recovery. PMID:21437359

Tjarnlund-Wolf, A; Hultman, K; Curtis, M A; Faull, R L M; Medcalf, R L; Jern, C

2011-06-01

271

Biomarker-based ovarian carcinoma typing: a histological investigation in the Ovarian Tumor Tissue Analysis consortium  

PubMed Central

Background Ovarian carcinoma is composed of five major histological types which associate with outcome and predict therapeutic response. Our aim was to evaluate histological type assessments across centres participating in the Ovarian Tumor Tissue Analysis (OTTA) consortium using an immunohistochemical (IHC) prediction model. Methods Tissue microarrays (TMAs) and clinical data were available for 524 pathologically confirmed ovarian carcinomas. Centralized IHC was performed for ARID1A, CDKN2A, DKK1, HNF1B, MDM2, PGR, TP53, TFF3, VIM, and WT1, and three histological type assessments were compared: the original pathologic type, an IHC-based calculated type (termed TB_COSPv2), and a WT1-assisted TMA core review. Results The concordance between TB_COSPv2 type and original type was 73%. Applying WT1-assisted core review, the remaining 27% discordant cases subdivided into unclassifiable (6%), TB_COSPv2 error (6%), and original type error (15%). The largest discordant subgroup was classified as endometrioid carcinoma (EC) by original type and as high-grade serous carcinoma (HGSC) by TB_COSPv2. When TB_COSPv2 classification was used, the difference in overall survival of EC compared to HGSC became significant (RR 0.60, 95% CI 0.37–0.93, p=0.021), consistent with previous reports. In addition, 71 cases with unclear original type could be histologically classified by TB_COSPv2. Conclusions Research cohorts, particularly those across different centres within consortia, show significant variability in original histological type diagnosis. Our IHC-based reclassification produced more homogeneous types with respect to outcome than original type. Impact Biomarker-based classification of ovarian carcinomas is feasible, improves comparability of results across research studies, and can reclassify cases which lack reliable original pathology. PMID:23880734

Köbel, Martin; Kalloger, Steve E.; Lee, Sandra; Duggan, Máire A.; Kelemen, Linda E.; Prentice, Leah; Kalli, Kimberly R.; Fridley, Brooke L.; Visscher, Daniel W.; Keeney, Gary L.; Vierkant, Robert A.; Cunningham, Julie M.; Chow, Christine; Ness, Roberta B.; Moysich, Kirsten; Edwards, Robert; Modugno, Francesmary; Bunker, Clareann; Wozniak, Eva L.; Benjamin, Elizabeth; Gayther, Simon A.; Gentry-Maharaj, Aleksandra; Menon, Usha; Gilks, C. Blake; Huntsman, David G.; Ramus, Susan J.; Goode, Ellen L.

2014-01-01

272

Determination of clenbuterol in porcine tissues using solid-phase extraction combined with ultrasound-assisted dispersive liquid-liquid microextraction and HPLC-UV detection.  

PubMed

A new pretreatment method, solid-phase extraction combined with dispersive liquid-liquid microextration (SPE-DLLME), was proposed in first time for the determination of clenbuterol (CLB) in porcine tissue samples. The tissue samples were firstly extracted by SPE, then its eluents were used as dispersant of the followed DLLME for further purification and enrichment of CLB. Various parameters (such as the type of SPE sorbent, the type and volume of elution solvent, the type and volume of extractant and dispersant, etc.) that affected the efficiency of the two steps were optimized. Good linearity of CLB was ranged from 0.19 ?g/kg to 192 ?g/kg with correlation coefficient (r²) of 0.9995. The limit of detection (LOD) was 0.07 ?g/kg (S/N=3) and the recoveries at three spiked levels were ranged from 87.9% to 103.6% with the relative standard deviation (RSD) less than 3.9% (n=3). Under the optimized conditions, the enrichment factor (EF) for CLB could up to 62 folds. The presented method that combined the advantages of SPE and DLLME, had higher selectivity than SPE method and was successfully applied to the determination of CLB in tissue samples. PMID:21131242

Liu, Baomi; Yan, Hongyuan; Qiao, Fengxia; Geng, Yuru

2011-01-01

273

Multi-Tissue Computational Modeling Analyzes Pathophysiology of Type 2 Diabetes in MKR Mice  

PubMed Central

Computational models using metabolic reconstructions for in silico simulation of metabolic disorders such as type 2 diabetes mellitus (T2DM) can provide a better understanding of disease pathophysiology and avoid high experimentation costs. There is a limited amount of computational work, using metabolic reconstructions, performed in this field for the better understanding of T2DM. In this study, a new algorithm for generating tissue-specific metabolic models is presented, along with the resulting multi-confidence level (MCL) multi-tissue model. The effect of T2DM on liver, muscle, and fat in MKR mice was first studied by microarray analysis and subsequently the changes in gene expression of frank T2DM MKR mice versus healthy mice were applied to the multi-tissue model to test the effect. Using the first multi-tissue genome-scale model of all metabolic pathways in T2DM, we found out that branched-chain amino acids' degradation and fatty acids oxidation pathway is downregulated in T2DM MKR mice. Microarray data showed low expression of genes in MKR mice versus healthy mice in the degradation of branched-chain amino acids and fatty-acid oxidation pathways. In addition, the flux balance analysis using the MCL multi-tissue model showed that the degradation pathways of branched-chain amino acid and fatty acid oxidation were significantly downregulated in MKR mice versus healthy mice. Validation of the model was performed using data derived from the literature regarding T2DM. Microarray data was used in conjunction with the model to predict fluxes of various other metabolic pathways in the T2DM mouse model and alterations in a number of pathways were detected. The Type 2 Diabetes MCL multi-tissue model may explain the high level of branched-chain amino acids and free fatty acids in plasma of Type 2 Diabetic subjects from a metabolic fluxes perspective. PMID:25029527

Kumar, Amit; Harrelson, Thomas; Lewis, Nathan E.; Gallagher, Emily J.; LeRoith, Derek; Shiloach, Joseph; Betenbaugh, Michael J.

2014-01-01

274

Broadband miniature fiber optic ultrasound generator.  

PubMed

This paper presents the design, fabrication and characterization of a broadband miniature fiber optic ultrasound generator based on photoacoustic (PA) ultrasound generation principle for biomedical ultrasound imaging and ultrasound non-destructive test (NDT) applications. A novel PA generation material, gold nanocomposite, was synthesized by directly reducing gold nanoparticles within polydimethylsiloxane (PDMS) through a one-pot protocol. The fiber optic ultrasound generator was fabricated by coating the gold nanocomposite on the tip of the optical fiber. The efficiency of the PA generation using gold nanocomposite was increased 10(5) compared to using aluminum thin film and 10(3) compared to using graphite mixed within epoxy. The ultrasound profile and the acoustic distribution have been characterized. The amplitude of the generated ultrasound signal was as high as 0.64 MPa and the bandwidth was more than 20 MHz. This paper also demonstrated its capability for ultrasound imaging of a tissue specimen. PMID:25089431

Zou, Xiaotian; Wu, Nan; Tian, Ye; Wang, Xingwei

2014-07-28

275

A study of the ultrasound-targeted microbubble destruction based triplex-forming oligodexinucleotide delivery system to inhibit tissue factor expression  

PubMed Central

The efficiency of cellular uptake of triplex-forming oligodexinucleotides (TFO), and the inhibition of tissue factor (TF) is low. The aim of the present study was to improve the absorption of TFO, and increase the inhibition of TF induced by shear stress both in vitro and in vivo, by using an ultrasound-targeted microbubble destruction (UTMD)-based delivery system. TFO-conjugated lipid ultrasonic microbubbles (TFO-M) were first constructed and characterised. The absorption of TFO was observed by a fluorescence-based method, and the inhibition of TF by immunofluorescence and quantitative polymerase chain reaction. ECV304 human umbilical vein endothelial cells were subjected to fluid shear stress for 6 h after treatment with TFO conjugated lipid ultrasonic microbubbles without sonication (TFO-M group); TFO alone; TFO conjugated lipid ultrasonic microbubbles, plus immediate sonication (TFO+U group and TFO-M+U group); or mock treated with 0.9% NaCl only (SSRE group). The in vivo experiments were established in a similar manner to the in vitro experiments, except that TFO or TFO-M was injected into rats through the tail vein. Six hours after the preparation of a carotid stenosis model, the rats were humanely sacrificed. The transfection efficiency of TFO in the TFO-M+U group was higher as compared with the TFO-M and TFO+U group (P<0.01). The protein and mRNA expression of TF in the TFO-M+U group was significantly decreased both in vitro and in vivo (P<0.01), as compared with the TFO-M, TFO+U and SSRE groups. The UTMD-based TFO delivery system promoted the absorption of TFO and the inhibition of TF, and was therefore considered to be favorable for preventing thrombosis induced by shear stress. PMID:25355395

LIANG, WEIHUA; ZHANG, WEIWEI; ZHAO, SHIFU; LI, QIANNING; YANG, YIMING; LIANG, HUA; CENG, RONGCHUAN

2015-01-01

276

A study of the ultrasound-targeted microbubble destruction based triplex-forming oligodexinucleotide delivery system to inhibit tissue factor expression.  

PubMed

The efficiency of cellular uptake of triplex?forming oligodexinucleotides (TFO), and the inhibition of tissue factor (TF) is low. The aim of the present study was to improve the absorption of TFO, and increase the inhibition of TF induced by shear stress both in vitro and in vivo, by using an ultrasound?targeted microbubble destruction (UTMD)?based delivery system. TFO?conjugated lipid ultrasonic microbubbles (TFO?M) were first constructed and characterised. The absorption of TFO was observed by a fluorescence?based method, and the inhibition of TF by immunofluorescence and quantitative polymerase chain reaction. ECV304 human umbilical vein endothelial cells were subjected to fluid shear stress for 6 h after treatment with TFO conjugated lipid ultrasonic microbubbles without sonication (TFO?M group); TFO alone; TFO conjugated lipid ultrasonic microbubbles, plus immediate sonication (TFO+U group and TFO?M+U group); or mock treated with 0.9% NaCl only (SSRE group). The in vivo experiments were established in a similar manner to the in vitro experiments, except that TFO or TFO?M was injected into rats through the tail vein. Six hours after the preparation of a carotid stenosis model, the rats were humanely sacrificed. The transfection efficiency of TFO in the TFO?M+U group was higher as compared with the TFO?M and TFO+U group (P<0.01). The protein and mRNA expression of TF in the TFO?M+U group was significantly decreased both in vitro and in vivo (P<0.01), as compared with the TFO?M, TFO+U and SSRE groups. The UTMD?based TFO delivery system promoted the -absorption of TFO and the inhibition of TF, and was therefore considered to be favorable for preventing thrombosis induced by shear stress. PMID:25355395

Liang, Weihua; Zhang, Weiwei; Zhao, Shifu; Li, Qianning; Yang, Yiming; Liang, Hua; Ceng, Rongchuan

2015-02-01

277

Variation in amount of wild-type transthyretin in different fibril and tissue types in ATTR amyloidosis.  

PubMed

Familial transthyretin (TTR) amyloidosis is caused by a mutation in the TTR gene, although wild-type (wt) TTR is also incorporated into the amyloid fibrils. Liver transplantation (LT) is the prevailing treatment of the disease and is performed in order to eliminate the mutant TTR from plasma. The outcome of the procedure is varied; especially problematic is a progressive cardiomyopathy seen in some patients, presumably caused by continued incorporation of wtTTR. What determines the discrepancy in outcome is not clear. We have previously shown that two structurally distinct amyloid fibrils (with or without fragmented ATTR) are found among ATTRV30M patients. In this study, we investigated the proportion of wtATTR in cardiac and adipose amyloid from patients having either fibril type. It was found that cardiac amyloid more easily incorporates wtTTR than adipose amyloid, offering a potential explanation for the vulnerability of cardiac tissue for continued amyloidosis after LT. In cardiac tissue, fibrils with fragmented ATTR contained a higher wt proportion than fibrils without, suggesting that continued incorporation of wtTTR after LT, perhaps, can take place more easily in these patients. In adipose tissue, a rapid increase in wt proportion after LT indicates that a rather fast turnover of the deposits must occur. A difference in wt proportion between the fibril types was seen post-LT but not pre-LT, possibly caused by differences in turnover rate. Conclusively, this study further establishes the basic dissimilarities between the two fibril types and demonstrates that their role in LT outcome needs to be further investigated. PMID:21107516

Ihse, Elisabet; Suhr, Ole B; Hellman, Ulf; Westermark, Per

2011-02-01

278

Application of ultrasound as pretreatment for extraction of podophyllotoxin from rhizomes of Podophyllum peltatum.  

PubMed

The effect of high-power ultrasound pretreatment on the extraction of podophyllotoxin from Podophyllum peltatum was investigated. Direct sonication by an ultrasound probe horn was applied at 24 kHz and a number of factors were investigated: particle size (0.18-0.6 mm), type of solvent (0-100% aqueous ethanol), ultrasonic treatment time (2-40 min), and power of ultrasound (0-100% power intensity, maximum power: 78 W). The optimal condition of ultrasound was achieved with 0.425-0.6 mm particle size, 10 min sonication time, 35 W ultrasound power, and water as the medium. There was no obvious degradation of podophyllotoxin with ultrasound under the applied conditions, and an improvement in extractability was observed. The SEM microscopic structure change of treated samples disclosed the effect of ultrasound on the tissue cells. The increased pore volume and surface area after ultrasonic treatment also confirmed the positive effect of ultrasound pretreatment on the extraction yield of podophyllotoxin from the plant cells. PMID:21664168

Zhao, Shuna; Baik, Oon Doo

2012-01-01

279

Validation of four-dimensional ultrasound for targeting in minimally-invasive beating-heart surgery  

NASA Astrophysics Data System (ADS)

Ultrasound is garnering significant interest as an imaging modality for surgical guidance, due to its affordability, real-time temporal resolution and ease of integration into the operating room. Minimally-invasive intracardiac surgery performed on the beating-heart prevents direct vision of the surgical target, and procedures such as mitral valve replacement and atrial septal defect closure would benefit from intraoperative ultrasound imaging. We propose that placing 4D ultrasound within an augmented reality environment, along with a patient-specific cardiac model and virtual representations of tracked surgical tools, will create a visually intuitive platform with sufficient image information to safely and accurately repair tissue within the beating heart. However, the quality of the imaging parameters, spatial calibration, temporal calibration and ECG-gating must be well characterized before any 4D ultrasound system can be used clinically to guide the treatment of moving structures. In this paper, we describe a comprehensive accuracy assessment framework that can be used to evaluate the performance of 4D ultrasound systems while imaging moving targets. We image a dynamic phantom that is comprised of a simple robot and a tracked phantom to which point-source, distance and spherical objects of known construction can be attached. We also follow our protocol to evaluate 4D ultrasound images generated in real-time by reconstructing ECG-gated 2D ultrasound images acquired from a tracked multiplanar transesophageal probe. Likewise, our evaluation framework allows any type of 4D ultrasound to be quantitatively assessed.

Pace, Danielle F.; Wiles, Andrew D.; Moore, John; Wedlake, Chris; Gobbi, David G.; Peters, Terry M.

2009-02-01

280

Biventricular function and glycemic load in type 1 diabetic children: Doppler tissue-imaging study.  

PubMed

To assess right- and left-ventricular function in children with type 1 diabetes mellitus (DM) as well as correlate cardiac function with diabetes duration and state of metabolic control. The present study included 30 patients with type 1 DM (group 1) and 20 apparently normal children with comparable age and sex as controls (group 2). All children were subjected to detailed history, clinical examination, and routine laboratory investigations, including glycated hemoglobin, as well as conventional echocardiographic and tissue Doppler examination. Children with type 1 DM have impaired diastolic function in both left and right ventricles before the development of systolic dysfunction when assessed with either conventional or tissue Doppler echocardiography. Resting heart rate in diabetic patients showed a significant positive correlation with mitral A flow velocity and a significant negative correlation with mitral and tricuspid E/A ratio. Regarding morphological parameters of the left ventricle, all dimensions and volumes were comparable between diabetic patients and controls; however, a significant positive correlation was found between interventricular septal thickness at diastole (IVSd), interventricular septal thickness at systole (IVSs), and left ventricular posterior wall at systole (LVPWs) and the duration of diabetes. Children with type 1 DM have impaired diastolic function in both left and right ventricles with normal systolic function when assessed with either conventional or tissue Doppler echocardiography. PMID:25304244

Khattab, Ahmed Anwer; Soliman, Mahmoud Ali

2015-02-01

281

Tissue Identification in Ultrasound Images using Rayleigh Local Parameter Santiago Aja-Fernaindez, Marcos Martin-Fernaindez and Carlos Alberola-L6pez*  

E-print Network

-Fernaindez, Marcos Martin-Fernaindez and Carlos Alberola-L6pez* LPI, ETSI Telecomunicacion, Universidad de Valladolid imaging systems, such as syn- thetic aperture radar (SAR), laser illuminated or ultrasound images

282

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

2013-05-01

283

Tissue-type specific systemin perception and the elusive systemin receptor  

PubMed Central

Systemin is a wound signaling peptide from tomato that is important for plant defenses against herbivory. The systemin receptor was initially identified as the tomato homolog of the brassinosteroid receptor BRI1, but genetic evidence argued against this finding. However, we found that BRI1 may function as an inappropriate systemin binding protein that does not activate the systemin signaling pathway. Here we provide evidence that systemin perception is localized in a tissue-type specific manner. Mesophyll protoplasts were not sensitive to systemin, while they responded to other elicitors. We hypothesize that the elusive systemin receptor is a protein with high similarity to BRI1 which is specifically localized in vascular tissue like the systemin precursor prosystemin. Binding of systemin to BRI1 may be an artifact of transgenic BRI1-overexpressing plants, but does not take place in wild type tomato cells. PMID:20592806

Hind, Sarah R; Malinowski, Robert; Yalamanchili, Roopa

2010-01-01

284

Exercise training does not improve myocardial diastolic tissue velocities in Type 2 diabetes  

Microsoft Academic Search

BACKGROUND: Myocardial diastolic tissue velocities are reduced already in newly onset Type 2 diabetes mellitus (T2D). Poor disease control may lead to left ventricular (LV) systolic dysfunction and heart failure. The aim of this study was to assess the effects of exercise training on myocardial diastolic function in T2D patients without ischemic heart disease. METHODS: 48 men (52.3 ± 5.6

Antti Loimaala; Kaj Groundstroem; Marjo Rinne; Arja Nenonen; Heini Huhtala; Ilkka Vuori

2007-01-01

285

Gene Prioritization for Type 2 Diabetes in Tissue-specific Protein Interaction Networks  

Microsoft Academic Search

Computationally prioritizing disease genes by large-scale bio-experimental data can provide important insights into the underlying mechanism of complex diseases. Here, we explore the topol- ogy of the protein-protein interaction network and apply the PageRank algorithm to identify can- didate genes relating to type 2 diabetes. Importantly, a novel idea is introduced to rank the disease genes in tissue-specific protein-protein interaction

Biao-Bin Jiang; Ji-Guang Wang; Jing-Fa Xiao; Yong Wang

2009-01-01

286

Proteomic profiling of cardiac tissue by isolation of nuclei tagged in specific cell types (INTACT)  

PubMed Central

The proper dissection of the molecular mechanisms governing the specification and differentiation of specific cell types requires isolation of pure cell populations from heterogeneous tissues and whole organisms. Here, we describe a method for purification of nuclei from defined cell or tissue types in vertebrate embryos using INTACT (isolation of nuclei tagged in specific cell types). This method, previously developed in plants, flies and worms, utilizes in vivo tagging of the nuclear envelope with biotin and the subsequent affinity purification of the labeled nuclei. In this study we successfully purified nuclei of cardiac and skeletal muscle from Xenopus using this strategy. We went on to demonstrate the utility of this approach by coupling the INTACT approach with liquid chromatography-tandem mass spectrometry (LC-MS/MS) proteomic methodologies to profile proteins expressed in the nuclei of developing hearts. From these studies we have identified the Xenopus orthologs of 12 human proteins encoded by genes, which when mutated in human lead to congenital heart disease. Thus, by combining these technologies we are able to identify tissue-specific proteins that are expressed and required for normal vertebrate organ development. PMID:24496632

Amin, Nirav M.; Greco, Todd M.; Kuchenbrod, Lauren M.; Rigney, Maggie M.; Chung, Mei-I; Wallingford, John B.; Cristea, Ileana M.; Conlon, Frank L.

2014-01-01

287

Silicon photonic micro-ring resonators strain and ultrasound  

E-print Network

of ultrasound is observing unborn children but ultra- sonography is widely used in medical and industrialSilicon photonic micro-ring resonators to sense strain and ultrasound Wouter Westerveld #12;This and ultrasound. The front cover illustrates a new type of ultrasound microphone, consisting of a silicon micro

288

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. PMID:23396888

Masciadri, N.; Ferranti, C.

2011-01-01

289

Protein dynamics in whole body and in splanchnic and leg tissues in type I diabetic patients.  

PubMed Central

To elucidate the mechanism of insulin's anticatabolic effect in humans, protein dynamics were evaluated in the whole-body, splanchnic, and leg tissues in six C-peptide-negative type I diabetic male patients in the insulin-deprived and insulin-treated states using two separate amino acid models (leucine and phenylalanine). L-(1-13C,15N)leucine, L-(ring-2H5)phenylalanine, and L-(ring-2H2) tyrosine were infused intravenously, and isotopic enrichments of [1-13C,15N]-leucine, (13C)leucine, (13C)ketoisocaproate, (2H5)phenylalanine, [2H4]tyrosine, (2H2)tyrosine, and 13CO2 were measured in arterial, hepatic vein, and femoral vein samples. Whole-body leucine flux, phenylalanine flux, and tyrosine flux were decreased (< 0.01) by insulin treatment, indicating an inhibition of protein breakdown. Moreover, insulin decreased (< 0.05) the rates of leucine oxidation and leucine transamination (P < 0.01), but the percent rate of ketoisocaproate oxidation was increased by insulin (P < 0.01). Insulin also reduced (< 0.01) whole-body protein synthesis estimated from both the leucine model (nonoxidative leucine disposal) and the phenylalanine model (disposal of phenylalanine not accounted by its conversion to tyrosine). Regional studies demonstrated that changes in whole body protein breakdown are accounted for by changes in both splanchnic and leg tissues. The changes in whole-body protein synthesis were not associated with changes in skeletal muscle (leg) protein synthesis but could be accounted for by the splanchnic region. We conclude that though insulin decreases whole-body protein breakdown in patients with type I diabetes by inhibition of protein breakdown in splanchnic and leg tissues, it selectively decreases protein synthesis in splanchnic tissues, which accounted for the observed decrease in whole-body protein synthesis. Insulin also augmented anabolism by decreasing leucine transamination. Images PMID:7769135

Nair, K S; Ford, G C; Ekberg, K; Fernqvist-Forbes, E; Wahren, J

1995-01-01

290

Effects of temperature and tissue type on Chrysomya rufifacies (Diptera: Calliphoridae) (Macquart) development.  

PubMed

The hairy maggot blow fly, Chrysomya rufifacies (Diptera: Calliphoridae), is a forensically important fly often encountered on human and other vertebrate remains in temperate and tropic regions throughout the world including Australia, Asia, Central America and North America. C. rufifacies was reared under controlled laboratory conditions on three muscle types (i.e., porcine, equine and canine) at three temperatures (i.e., 20.8, 24.8 and 28.3°C). Rate of larval weight gain across time was statistically significant between muscle types (P?0.0001) and approaching significance across time between temperatures (P=0.0511). This research represents the first development study for C. rufifacies from central Texas, USA and the first study to examine the impact of tissue type on its development. Furthermore, these data, when compared to those available in the literature, indicate developmental differences that could be due to genetic differences in populations or possibly methods employed during the studies. Caution should be emphasized when applying development data for this species from one region to forensic investigations in other ecoregions as such differences in development based on tissue fed upon by larvae, population genetics, and methodologies used in the studies could represent error in estimating the time of colonization. PMID:25447170

Flores, Micah; Longnecker, Michael; Tomberlin, Jeffery K

2014-10-13

291

Transvaginal ultrasound  

MedlinePLUS

... ovary, ultrasound imaging of pelvic structures. In: Lentz GM, Lobo RA, Gershenson DM, Katz VL, eds. Comprehensive ... cell neoplasms, sex-cord stromal tumors. In: Lentz GM, Lobo RA, Gershenson DM, Katz VL, eds. Comprehensive ...

292

Soft tissue sarcomas and central nervous system tumors in children with neurofibromatosis type 1  

Microsoft Academic Search

Objects  We aim to evaluate the characteristics of pediatric patients with neurofibromatosis type 1 (NF1) who developed soft tissue\\u000a sarcomas (STSs) and central nervous system (CNS) tumors that have been followed up in our center.\\u000a \\u000a \\u000a \\u000a \\u000a Materials and methods  Medical records of children with NF1 were retrospectively analyzed.\\u000a \\u000a \\u000a \\u000a Results  There were 78 patients who met at least two diagnostic criteria for NF1. The median

Emre Cecen; Dilek Ince; Kamer Mutafoglu Uysal; Erdener Ozer; Riza Cetingoz; Ali Aykan Ozguven; Handan Cakmakci; Faik Sarialioglu; Nur Olgun

293

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

294

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. PMID:19932598

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

2010-01-01

295

ULTRASONIC IMAGING 3, 342-351 (1981) COMPUTERIZED ULTRASOUND TOMOGRAPHY  

E-print Network

inherent, at present, in the method. Ultrasound computed tomography (CT), on the other hand, provides by radiographic methods. Much of the previous work in ultrasound CT has concentrated on soft tissues (weakly-10). The excised brain has also been imaged using ultrasound CT [ll]. The two acoustic parameters which have

Illinois at Urbana-Champaign, University of

296

Perspectives in clinical uses of high-intensity focused ultrasound  

Microsoft Academic Search

Focused ultrasound holds promise in a large number of therapeutic applications. It has long been known that high intensity focused ultrasound can kill tissue through coagulative necrosis. However, it is only in recent years that practical clinical applications are becoming possible, with the development of high power ultrasound phased arrays and noninvasive monitoring methods. These technologies, combined with more sophisticated

G. T. Clement

2004-01-01

297

MEMS-Based Scanner Dedicated for Ultrasound Medical Imaging  

E-print Network

MEMS-Based Scanner Dedicated for Ultrasound Medical Imaging M. Hajj Hassan and M. Sawan Polystim, which is reflected by tissues and organs. The image quality of medical ultrasound was enhanced, the development of a micro electromechanical scanner incorporating high frequency ultrasound transducer operating

Peter, Yves-Alain

298

Ultrasound medical image deconvolution using CLEAN L.-T. Chiraa  

E-print Network

Ultrasound medical image deconvolution using CLEAN algorithm L.-T. Chiraa , J.-M. Giraultb , T reconstruction problem of ultrasound medical images using blind deconvolution algorithm has been recognized tissues scatters number. 1 Introduction The medical diagnostic using ultrasounds has intensively used

Boyer, Edmond

299

Breast biopsy - ultrasound  

MedlinePLUS

Biopsy - breast - ultrasound; Ultrasound-guided breast biopsy; Core needle breast biopsy - ultrasound ... to evaluate abnormal findings on a mammogram or breast ultrasound , or during a physical exam. To determine whether ...

300

An optimized ultrasound-assisted extraction and simultaneous quantification of 26 characteristic components with four structure types in functional foods from ginkgo seeds.  

PubMed

An optimized method of ultrasound-assisted extraction followed by ultra-high-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (UAE-UHPLC-TQ/MS(2)) was proposed for the simultaneous extraction and determination of 26 characteristic components covering four structure types (flavonoids, terpene lactones, ginkgolic acids and phenylpropanols) in ginkgo seeds (GSs). The UAE parameters (ultrasound power, time and solvent-to-material ratio) were optimized using a response surface methodology. This is the first report of the simultaneous analysis of 26 compounds in Ginkgo biloba using UHPLC-TQ/MS(2); this analysis afforded good linearity, precision, repeatability and accuracy. UAE-UHPLC-TQ/MS(2) was successfully applied to ginkgo seed samples, and the analysis showed that GSs are rich in terpene lactones and could be selected as a healthy food resource. The results suggest that UAE-UHPLC-TQ/MS(2) might be able to be utilized as a tool for the quality assessment of samples from GSs or other related products using flavonoids, terpene lactones, ginkgolic acids and phenylpropanols as markers. PMID:24731329

Zhou, Guisheng; Yao, Xin; Tang, Yuping; Qian, Dawei; Su, Shulan; Zhang, Li; Jin, Chun; Qin, Yong; Duan, Jin-ao

2014-09-01

301

Study of factors affecting the magnitude and nature of ultrasound exposure with in vitro set-ups.  

PubMed

Therapeutic ultrasound is a clinically applied method to improve fracture healing and holds great potential as a manipulator of biologic material relevant to tissue engineering approaches. Unfortunately, the cell stimulating property of ultrasound is not known, which inhibits the optimal use of this technique. Additionally, many in vitro studies in this field use ultrasound configurations that are vulnerable to errors during calibration and use. These errors arise from the structural simplicity and incomplete characterization of these configurations. In this study, pulse-echo ultrasound, laser Doppler vibrometry and Schlieren imaging were applied to noninvasively characterize common in vitro experimental configurations. Fine wire thermocouple measurements were conducted to characterize any possible temperature rise during the ultrasound exposures. The results quantified the frequency dependent sound transmission through culture wells and the standing wave effect within the cell volume. These effects can cause uncertainty of up to 700% in the actual ultrasound exposure experienced by the cell. A temperature rise of 2.7°C was measured from an ultrasound configuration commonly used in vitro ultrasound studies. Furthermore, wave mode conversion in culture wells was observed, emphasizing the complexity of these sonications. Similar type Lamb waves have been observed in bone in vivo. Thus, Lamb waves may be a mechanism for stimulating the cells. PMID:22425382

Leskinen, Jarkko J; Hynynen, Kullervo

2012-05-01

302

Cranial Ultrasound/Head Ultrasound  

MedlinePLUS

... collects the sounds that bounce back and a computer then uses those sound waves to create an ... Ultrasound scanners consist of a console containing a computer and electronics, a video display screen and a ...

303

Adipocyte Hypertrophy, Inflammation and Fibrosis Characterize Subcutaneous Adipose Tissue of Healthy, Non-Obese Subjects Predisposed to Type 2 Diabetes  

PubMed Central

Background The adipose tissue is important for development of insulin resistance and type 2 diabetes and adipose tissue dysfunction has been proposed as an underlying cause. In the present study we investigated presence of adipocyte hypertrophy, and gene expression pattern of adipose tissue dysfunction in the subcutaneous adipose tissue of healthy, non-obese subjects predisposed to type 2 diabetes compared to matched control subjects with no known genetic predisposition for type 2 diabetes. Method Seventeen healthy and non-obese subjects with known genetic predisposition for type 2 diabetes (first-degree relatives, FDRs) and 17 control subjects were recruited. The groups were matched for gender and BMI and had similar age. Glucose tolerance was determined by an oral glucose tolerance test and insulin sensitivity was calculated using HOMA-index. Blood samples were collected and subcutaneous abdominal adipose tissue biopsies obtained for gene expression analysis and adipocyte cell size measurement. Results Our findings show that, in spite of similar age, BMI and percent body fat, FDRs displayed adipocyte hypertrophy, as well as higher waist/hip ratio, fasting insulin levels, HOMA-IR and serum triglycerides. Adipocyte hypertrophy in the FDR group, but not among controls, was associated with measures of impaired insulin sensitivity. The adipocyte hypertrophy was accompanied by increased inflammation and Wnt-signal activation. In addition, signs of tissue remodeling and fibrosis were observed indicating presence of early alterations associated with adipose tissue dysfunction in the FDRs. Conclusion Genetic predisposition for type 2 diabetes is associated with impaired insulin sensitivity, adipocyte hypertrophy and other markers of adipose tissue dysfunction. A dysregulated subcutaneous adipose tissue may be a major susceptibility factor for later development of type 2 diabetes. PMID:25148116

Henninger, A. M. Josefin; Eliasson, Björn; Jenndahl, Lachmi E.; Hammarstedt, Ann

2014-01-01

304

Propolis Modifies Collagen Types I and III Accumulation in the Matrix of Burnt Tissue.  

PubMed

Wound healing represents an interactive process which requires highly organized activity of various cells, synthesizing cytokines, growth factors, and collagen. Collagen types I and III, serving as structural and regulatory molecules, play pivotal roles during wound healing. The aim of this study was to compare the propolis and silver sulfadiazine therapeutic efficacy throughout the quantitative and qualitative assessment of collagen types I and III accumulation in the matrix of burnt tissues. Burn wounds were inflicted on pigs, chosen for the evaluation of wound repair because of many similarities between pig and human skin. Isolated collagen types I and III were estimated by the surface plasmon resonance method with a subsequent collagenous quantification using electrophoretic and densitometric analyses. Propolis burn treatment led to enhanced collagens and its components expression, especially during the initial stage of the study. Less expressed changes were observed after silver sulfadiazine (AgSD) application. AgSD and, with a smaller intensity, propolis stimulated accumulation of collagenous degradation products. The assessed propolis therapeutic efficacy, throughout quantitatively and qualitatively analyses of collagen types I and III expression and degradation in wounds matrix, may indicate that apitherapeutic agent can generate favorable biochemical environment supporting reepithelization. PMID:23781260

Olczyk, Pawel; Wisowski, Grzegorz; Komosinska-Vassev, Katarzyna; Stojko, Jerzy; Klimek, Katarzyna; Olczyk, Monika; Kozma, Ewa M

2013-01-01

305

Propolis Modifies Collagen Types I and III Accumulation in the Matrix of Burnt Tissue  

PubMed Central

Wound healing represents an interactive process which requires highly organized activity of various cells, synthesizing cytokines, growth factors, and collagen. Collagen types I and III, serving as structural and regulatory molecules, play pivotal roles during wound healing. The aim of this study was to compare the propolis and silver sulfadiazine therapeutic efficacy throughout the quantitative and qualitative assessment of collagen types I and III accumulation in the matrix of burnt tissues. Burn wounds were inflicted on pigs, chosen for the evaluation of wound repair because of many similarities between pig and human skin. Isolated collagen types I and III were estimated by the surface plasmon resonance method with a subsequent collagenous quantification using electrophoretic and densitometric analyses. Propolis burn treatment led to enhanced collagens and its components expression, especially during the initial stage of the study. Less expressed changes were observed after silver sulfadiazine (AgSD) application. AgSD and, with a smaller intensity, propolis stimulated accumulation of collagenous degradation products. The assessed propolis therapeutic efficacy, throughout quantitatively and qualitatively analyses of collagen types I and III expression and degradation in wounds matrix, may indicate that apitherapeutic agent can generate favorable biochemical environment supporting reepithelization. PMID:23781260

Olczyk, Pawel; Wisowski, Grzegorz; Komosinska-Vassev, Katarzyna; Stojko, Jerzy; Klimek, Katarzyna; Olczyk, Monika; Kozma, Ewa M.

2013-01-01

306

An atlas of active enhancers across human cell types and tissues  

NASA Astrophysics Data System (ADS)

Enhancers control the correct temporal and cell-type-specific activation of gene expression in multicellular eukaryotes. Knowing their properties, regulatory activity and targets is crucial to understand the regulation of differentiation and homeostasis. Here we use the FANTOM5 panel of samples, covering the majority of human tissues and cell types, to produce an atlas of active, in vivo-transcribed enhancers. We show that enhancers share properties with CpG-poor messenger RNA promoters but produce bidirectional, exosome-sensitive, relatively short unspliced RNAs, the generation of which is strongly related to enhancer activity. The atlas is used to compare regulatory programs between different cells at unprecedented depth, to identify disease-associated regulatory single nucleotide polymorphisms, and to classify cell-type-specific and ubiquitous enhancers. We further explore the utility of enhancer redundancy, which explains gene expression strength rather than expression patterns. The online FANTOM5 enhancer atlas represents a unique resource for studies on cell-type-specific enhancers and gene regulation.

Andersson, Robin; Gebhard, Claudia; Miguel-Escalada, Irene; Hoof, Ilka; Bornholdt, Jette; Boyd, Mette; Chen, Yun; Zhao, Xiaobei; Schmidl, Christian; Suzuki, Takahiro; Ntini, Evgenia; Arner, Erik; Valen, Eivind; Li, Kang; Schwarzfischer, Lucia; Glatz, Dagmar; Raithel, Johanna; Lilje, Berit; Rapin, Nicolas; Bagger, Frederik Otzen; Jørgensen, Mette; Andersen, Peter Refsing; Bertin, Nicolas; Rackham, Owen; Burroughs, A. Maxwell; Baillie, J. Kenneth; Ishizu, Yuri; Shimizu, Yuri; Furuhata, Erina; Maeda, Shiori; Negishi, Yutaka; Mungall, Christopher J.; Meehan, Terrence F.; Lassmann, Timo; Itoh, Masayoshi; Kawaji, Hideya; Kondo, Naoto; Kawai, Jun; Lennartsson, Andreas; Daub, Carsten O.; Heutink, Peter; Hume, David A.; Jensen, Torben Heick; Suzuki, Harukazu; Hayashizaki, Yoshihide; Müller, Ferenc; Consortium, The Fantom; Forrest, Alistair R. R.; Carninci, Piero; Rehli, Michael; Sandelin, Albin

2014-03-01

307

An atlas of active enhancers across human cell types and tissues.  

PubMed

Enhancers control the correct temporal and cell-type-specific activation of gene expression in multicellular eukaryotes. Knowing their properties, regulatory activity and targets is crucial to understand the regulation of differentiation and homeostasis. Here we use the FANTOM5 panel of samples, covering the majority of human tissues and cell types, to produce an atlas of active, in vivo-transcribed enhancers. We show that enhancers share properties with CpG-poor messenger RNA promoters but produce bidirectional, exosome-sensitive, relatively short unspliced RNAs, the generation of which is strongly related to enhancer activity. The atlas is used to compare regulatory programs between different cells at unprecedented depth, to identify disease-associated regulatory single nucleotide polymorphisms, and to classify cell-type-specific and ubiquitous enhancers. We further explore the utility of enhancer redundancy, which explains gene expression strength rather than expression patterns. The online FANTOM5 enhancer atlas represents a unique resource for studies on cell-type-specific enhancers and gene regulation. PMID:24670763

Andersson, Robin; Gebhard, Claudia; Miguel-Escalada, Irene; Hoof, Ilka; Bornholdt, Jette; Boyd, Mette; Chen, Yun; Zhao, Xiaobei; Schmidl, Christian; Suzuki, Takahiro; Ntini, Evgenia; Arner, Erik; Valen, Eivind; Li, Kang; Schwarzfischer, Lucia; Glatz, Dagmar; Raithel, Johanna; Lilje, Berit; Rapin, Nicolas; Bagger, Frederik Otzen; Jørgensen, Mette; Andersen, Peter Refsing; Bertin, Nicolas; Rackham, Owen; Burroughs, A Maxwell; Baillie, J Kenneth; Ishizu, Yuri; Shimizu, Yuri; Furuhata, Erina; Maeda, Shiori; Negishi, Yutaka; Mungall, Christopher J; Meehan, Terrence F; Lassmann, Timo; Itoh, Masayoshi; Kawaji, Hideya; Kondo, Naoto; Kawai, Jun; Lennartsson, Andreas; Daub, Carsten O; Heutink, Peter; Hume, David A; Jensen, Torben Heick; Suzuki, Harukazu; Hayashizaki, Yoshihide; Müller, Ferenc; Forrest, Alistair R R; Carninci, Piero; Rehli, Michael; Sandelin, Albin

2014-03-27

308

Connective Tissue Reflex Massage for Type 2 Diabetic Patients with Peripheral Arterial Disease: Randomized Controlled Trial  

PubMed Central

The objective of this study was to evaluate the efficacy of connective tissue massage to improve blood circulation and intermittent claudication symptoms in type 2 diabetic patients. A randomized, placebo-controlled trial was undertaken. Ninety-eight type 2 diabetes patients with stage I or II-a peripheral arterial disease (PAD) (Leriche-Fontaine classification) were randomly assigned to a massage group or to a placebo group treated using disconnected magnetotherapy equipment. Peripheral arterial circulation was determined by measuring differential segmental arterial pressure, heart rate, skin temperature, oxygen saturation and skin blood flow. Measurements were taken before and at 30?min, 6 months and 1 year after the 15-week treatment. After the 15-week program, the groups differed (P < .05) in differential segmental arterial pressure in right lower limb (lower one-third of thigh, upper and lower one-third of leg) and left lower limb (lower one-third of thigh and upper and lower one-third of leg). A significant difference (P < .05) was also observed in skin blood flow in digits 1 and 4 of right foot and digits 2, 4 and 5 of left foot. ANOVA results were significant (P < .05) for right and left foot oxygen saturation but not for heart rate and temperature. At 6 months and 1 year, the groups differed in differential segmental arterial pressure in upper third of left and right legs. Connective tissue massage improves blood circulation in the lower limbs of type 2 diabetic patients at stage I or II-a and may be useful to slow the progression of PAD. PMID:19933770

Castro-Sánchez, Adelaida María; Moreno-Lorenzo, Carmen; Matarán-Peñarrocha, Guillermo A.; Feriche-Fernández-Castanys, Belen; Granados-Gámez, Genoveva; Quesada-Rubio, José Manuel

2011-01-01

309

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

310

Immunocytochemical demonstration of tissue-type plasminogen activator in endocrine cells of the rat pituitary gland  

PubMed Central

We immunocytochemically stained rat pituitary glands using antibodies against plasminogen activators of the tissue type (t-PA) and the urokinase type (u-PA). A large population of endocrine cells in the anterior lobe of the gland displayed intense cytoplasmic immunoreactivity with anti-t-PA. In some areas of the intermediate lobe we found a weak staining, and we observed weakly staining granular structures in the posterior lobe. Controls included absorption of the antibodies with highly purified t-PA. In addition, SDS PAGE followed by immunoblotting of pituitary gland extracts revealed only one band with an electrophoretic mobility similar to that of t-PA when stained with anti-t-PA IgG. No u-PA immunoreactivity was detected in the rat pituitary gland. Sequential staining experiments using antibodies against growth hormone and t-PA demonstrated that the t-PA- immunoreactive cells constitute a large subpopulation of the growth hormone-containing cells. These findings represent the first direct evidence for the presence of t-PA in cell types other than endothelial cells in the intact normal organism. In this article we discuss the implications of the results for a possible role of t-PA in the posttranslational processing of prohormones. PMID:3891762

1985-01-01

311

Low-frequency quantitative ultrasound imaging of cell death in vivo  

SciTech Connect

Purpose: Currently, no clinical imaging modality is used routinely to assess tumor response to cancer therapies within hours to days of the delivery of treatment. Here, the authors demonstrate the efficacy of ultrasound at a clinically relevant frequency to quantitatively detect changes in tumors in response to cancer therapies using preclinical mouse models.Methods: Conventional low-frequency and corresponding high-frequency ultrasound (ranging from 4 to 28 MHz) were used along with quantitative spectroscopic and signal envelope statistical analyses on data obtained from xenograft tumors treated with chemotherapy, x-ray radiation, as well as a novel vascular targeting microbubble therapy.Results: Ultrasound-based spectroscopic biomarkers indicated significant changes in cell-death associated parameters in responsive tumors. Specifically changes in the midband fit, spectral slope, and 0-MHz intercept biomarkers were investigated for different types of treatment and demonstrated cell-death related changes. The midband fit and 0-MHz intercept biomarker derived from low-frequency data demonstrated increases ranging approximately from 0 to 6 dBr and 0 to 8 dBr, respectively, depending on treatments administrated. These data paralleled results observed for high-frequency ultrasound data. Statistical analysis of ultrasound signal envelope was performed as an alternative method to obtain histogram-based biomarkers and provided confirmatory results. Histological analysis of tumor specimens indicated up to 61% cell death present in the tumors depending on treatments administered, consistent with quantitative ultrasound findings indicating cell death. Ultrasound-based spectroscopic biomarkers demonstrated a good correlation with histological morphological findings indicative of cell death (r{sup 2}= 0.71, 0.82; p < 0.001).Conclusions: In summary, the results provide preclinical evidence, for the first time, that quantitative ultrasound used at a clinically relevant frequency, in addition to high-frequency ultrasound, can detect tissue changes associated with cell death in vivo in response to cancer treatments.

Sadeghi-Naini, Ali; Falou, Omar; Czarnota, Gregory J. [Imaging Research – Physical Science, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada) [Imaging Research – Physical Science, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada); Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada); Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada); Department of Radiation Oncology, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada); Papanicolau, Naum; Tadayyon, Hadi [Imaging Research – Physical Science, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada and Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada)] [Imaging Research – Physical Science, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada and Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada); Lee, Justin [Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada and Department of Radiation Oncology, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada)] [Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada and Department of Radiation Oncology, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5 (Canada); Zubovits, Judit [Department of Pathology, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada)] [Department of Pathology, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada); Sadeghian, Alireza [Department of Computer Science, Ryerson University, Toronto, Ontario M5B 2K3 (Canada)] [Department of Computer Science, Ryerson University, Toronto, Ontario M5B 2K3 (Canada); Karshafian, Raffi [Department of Physics, Ryerson University, Toronto, Ontario M5B 2K3 (Canada)] [Department of Physics, Ryerson University, Toronto, Ontario M5B 2K3 (Canada); Al-Mahrouki, Azza; Giles, Anoja [Imaging Research – Physical Science, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada and Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada)] [Imaging Research – Physical Science, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5, Canada and Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario M4N 3M5 (Canada); Kolios, Michael C. [Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5, Canada and Department of Physics, Ryerson University, Toronto, Ontario M5B 2K3 (Canada)] [Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Ontario M4N 3M5, Canada and Department of Physics, Ryerson University, Toronto, Ontario M5B 2K3 (Canada)

2013-08-15

312

Ultrasound Transducers  

NASA Astrophysics Data System (ADS)

Ultrasound imaging modality has the major advantage, as compared to other medical imaging modes, to provide real-time acquisitions. It is a cheap modality compared to MRI and others, and it is non-invasive. One interest in using ultrasound imaging is to study the dynamic behaviour of various organs such as arteries, liver, heart. Today's scanners allow the visualization of the structures in gray scale images and the visualization of the flow information in color Doppler mode images. Both information can be acquired simultaneously. In this chapter we will present the basic principles leading to the design of probes.

Bertora, Franco

313

Destruction of Tissue, Cells and Organelles in Type 1 Diabetic Rats Presented at Macromolecular Resolution  

PubMed Central

Finding alternatives for insulin therapy and making advances in etiology of type 1 diabetes benefits from a full structural and functional insight into Islets of Langerhans. Electron microscopy (EM) can visualize Islet morphology at the highest possible resolution, however, conventional EM only provides biased snapshots and lacks context. We developed and employed large scale EM and compiled a resource of complete cross sections of rat Islets during immuno-destruction to provide unbiased structural insight of thousands of cells at macromolecular resolution. The resource includes six datasets, totalling 25.000 micrographs, annotated for cellular and ultrastructural changes during autoimmune diabetes. Granulocytes are attracted to the endocrine tissue, followed by extravasation of a pleiotrophy of leukocytes. Subcellullar changes in beta cells include endoplasmic reticulum stress, insulin degranulation and glycogen accumulation. Rare findings include erythrocyte extravasation and nuclear actin-like fibers. While we focus on a rat model of autoimmune diabetes, our approach is general applicable. PMID:23652855

Ravelli, Raimond B. G.; Kalicharan, Ruby D.; Avramut, M. Cristina; Sjollema, Klaas A.; Pronk, Joachim W.; Dijk, Freark; Koster, Abraham J.; Visser, Jeroen T. J.; Faas, Frank G. A.; Giepmans, Ben N. G.

2013-01-01

314

Beneficial Autoimmunity at Body Surfaces – Immune Surveillance and Rapid Type 2 Immunity Regulate Tissue Homeostasis and Cancer  

PubMed Central

Epithelial cells (ECs) line body surface tissues and provide a physicochemical barrier to the external environment. Frequent microbial and non-microbial challenges such as those imposed by mechanical disruption, injury or exposure to noxious environmental substances including chemicals, carcinogens, ultraviolet-irradiation, or toxins cause activation of ECs with release of cytokines and chemokines as well as alterations in the expression of cell-surface ligands. Such display of epithelial stress is rapidly sensed by tissue-resident immunocytes, which can directly interact with self-moieties on ECs and initiate both local and systemic immune responses. ECs are thus key drivers of immune surveillance at body surface tissues. However, ECs have a propensity to drive type 2 immunity (rather than type 1) upon non-invasive challenge or stress – a type of immunity whose regulation and function still remain enigmatic. Here, we review the induction and possible role of type 2 immunity in epithelial tissues and propose that rapid immune surveillance and type 2 immunity are key regulators of tissue homeostasis and carcinogenesis. PMID:25101088

Dalessandri, Tim; Strid, Jessica

2014-01-01

315

Ontology-aware classification of tissue and cell-type signals in gene expression profiles across platforms and technologies  

PubMed Central

Motivation: Leveraging gene expression data through large-scale integrative analyses for multicellular organisms is challenging because most samples are not fully annotated to their tissue/cell-type of origin. A computational method to classify samples using their entire gene expression profiles is needed. Such a method must be applicable across thousands of independent studies, hundreds of gene expression technologies and hundreds of diverse human tissues and cell-types. Results: We present Unveiling RNA Sample Annotation (URSA) that leverages the complex tissue/cell-type relationships and simultaneously estimates the probabilities associated with hundreds of tissues/cell-types for any given gene expression profile. URSA provides accurate and intuitive probability values for expression profiles across independent studies and outperforms other methods, irrespective of data preprocessing techniques. Moreover, without re-training, URSA can be used to classify samples from diverse microarray platforms and even from next-generation sequencing technology. Finally, we provide a molecular interpretation for the tissue and cell-type models as the biological basis for URSA’s classifications. Availability and implementation: An interactive web interface for using URSA for gene expression analysis is available at: ursa.princeton.edu. The source code is available at https://bitbucket.org/youngl/ursa_backend. Contact: ogt@cs.princeton.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:24037214

Lee, Young-suk; Krishnan, Arjun; Zhu, Qian; Troyanskaya, Olga G.

2013-01-01

316

Individual-specific muscle maximum force estimation using ultrasound for ankle joint torque prediction using an EMG-driven Hill-type model.  

PubMed

EMG-driven models can be used to estimate muscle force in biomechanical systems. Collected and processed EMG readings are used as the input of a dynamic system, which is integrated numerically. This approach requires the definition of a reasonably large set of parameters. Some of these vary widely among subjects, and slight inaccuracies in such parameters can lead to large model output errors. One of these parameters is the maximum voluntary contraction force (F(om)). This paper proposes an approach to find F(om) by estimating muscle physiological cross-sectional area (PCSA) using ultrasound (US), which is multiplied by a realistic value of maximum muscle specific tension. Ultrasound is used to measure muscle thickness, which allows for the determination of muscle volume through regression equations. Soleus, gastrocnemius medialis and gastrocnemius lateralis PCSAs are estimated using published volume proportions among leg muscles, which also requires measurements of muscle fiber length and pennation angle by US. F(om) obtained by this approach and from data widely cited in the literature was used to comparatively test a Hill-type EMG-driven model of the ankle joint. The model uses 3 EMGs (Soleus, gastrocnemius medialis and gastrocnemius lateralis) as inputs with joint torque as the output. The EMG signals were obtained in a series of experiments carried out with 8 adult male subjects, who performed an isometric contraction protocol consisting of 10s step contractions at 20% and 60% of the maximum voluntary contraction level. Isometric torque was simultaneously collected using a dynamometer. A statistically significant reduction in the root mean square error was observed when US-obtained F(om) was used, as compared to F(om) from the literature. PMID:20541763

de Oliveira, Liliam Fernandes; Menegaldo, Luciano Luporini

2010-10-19

317

Tissue microstructure, physicochemical properties, and bioactive compound locations in different sweet pepper types.  

PubMed

This article focuses on the location and content of some bioactive compounds in three different California sweet pepper types (red, green and yellow). The location was studied using different microscopic techniques, such as scanning electron microscopy at low temperatures (cryo-SEM) and light microscopy. Several physicochemical properties of the samples (carotenoid content, total soluble phenol content, antioxidant activity, dietary fibre content, total soluble solids content, pH and textural properties) were also examined. The degree of compaction and structuring of the cell wall was found to be indirectly related to solute transport at the cellular level and directly related to total dietary fibre content. The three types of pepper displayed formation and accumulation of phenolic aggregates and an active circulation of solutes. Yellow pepper tissue had the most labile cell walls and the highest transport of solutes. Red peppers could be suitable for obtaining extracts rich in carotenoid compounds, yellow peppers for obtaining phenolic compounds with a high antioxidant activity and green peppers for extracts with high dietary fibre content. PMID:23996968

Hernández-Carrión, María; Hernando, Isabel; Quiles, Amparo

2015-01-01

318

Cell type specific gene expression analysis of prostate needle biopsies resolves tumor tissue heterogeneity.  

PubMed

A lack of cell surface markers for the specific identification, isolation and subsequent analysis of living prostate tumor cells hampers progress in the field. Specific characterization of tumor cells and their microenvironment in a multi-parameter molecular assay could significantly improve prognostic accuracy for the heterogeneous prostate tumor tissue. Novel functionalized gold-nano particles allow fluorescence-based detection of absolute mRNA expression levels in living cells by fluorescent activated flow cytometry (FACS). We use of this technique to separate prostate tumor and benign cells in human prostate needle biopsies based on the expression levels of the tumor marker alpha-methylacyl-CoA racemase (AMACR). We combined RNA and protein detection of living cells by FACS to gate for epithelial cell adhesion molecule (EPCAM) positive tumor and benign cells, EPCAM/CD45 double negative mesenchymal cells and CD45 positive infiltrating lymphocytes. EPCAM positive epithelial cells were further sub-gated into AMACR high and low expressing cells. Two hundred cells from each population and several biopsies from the same patient were analyzed using a multiplexed gene expression profile to generate a cell type resolved profile of the specimen. This technique provides the basis for the clinical evaluation of cell type resolved gene expression profiles as pre-therapeutic prognostic markers for prostate cancer. PMID:25514598

Krönig, Malte; Walter, Max; Drendel, Vanessa; Werner, Martin; Jilg, Cordula A; Richter, Andreas S; Backofen, Rolf; McGarry, David; Follo, Marie; Schultze-Seemann, Wolfgang; Schüle, Roland

2015-01-20

319

Alteration of Gene Expression Profile in Niemann-Pick Type C Mice Correlates with Tissue Damage and Oxidative Stress  

Microsoft Academic Search

BackgroundNiemann-Pick type C disease (NPC) is a neurovisceral lipid storage disorder mainly characterized by unesterified cholesterol accumulation in lysosomal\\/late endosomal compartments, although there is also an important storage for several other kind of lipids. The main tissues affected by the disease are the liver and the cerebellum. Oxidative stress has been described in various NPC cells and tissues, such as

Mary C. Vázquez; Talía del Pozo; Fermín A. Robledo; Gonzalo Carrasco; Leonardo Pavez; Felipe Olivares; Mauricio González; Silvana Zanlungo

2011-01-01

320

Endocytosis and intracellular processing of tissue-type plasminogen activator by rat liver cells in vivo.  

PubMed Central

Endocytosis of tissue-type plasminogen activator (t-PA) by different types of rat liver cells was studied in immunocytochemically labelled cryosections as well as in biochemical experiments. For morphological localization of the ligand in different endocytic compartments involved in its catabolism, rat livers were fixed at various times (1-24 min) after injection of t-PA. Late-endosomal and lysosomal compartments were identified by double-labelling the sections with antibodies to the lysosomal proteins glycoprotein Igp 120 and cathepsin D. In liver t-PA was localized in sinusoidal endothelial cells (EC), parenchymal cells (PC) and to some extent in Kupffer cells (KC), indicating that it is internalized and degraded in all three cell types. In specimens fixed 6 min after injection PC, EC and KC were found to contribute to 69, 24 and 7% respectively of total t-PA endocytosed. The transfer from late endosomes to lysosomes was found to be faster in EC than in PC. The morphological findings were supported by studies of the endocytic mechanisms employing isolated perfused livers and primary hepatocytes. The presence of monensin, an inhibitor of lysosomal protein degradation, reduced the amount of t-PA degraded to about 50% of the control values. The catalytic site seems not to be required for the catabolism of t-PA in hepatic cells. The inhibition of t-PA by D-phenylalanyl-L-prolylarginyl-chloromethane did not influence receptor recognition and catabolic processing, as determined in morphological studies using labelled cryosections, in binding studies employing liver cell membranes and primary hepatocytes, as well as in liver-perfusion experiments. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. PMID:1554369

Stang, E; Krause, J; Seydel, W; Berg, T; Roos, N

1992-01-01

321

Cellular localization of type 1 plasminogen activator inhibitor messenger RNA and protein in murine renal tissue.  

PubMed Central

Type 1 plasminogen activator inhibitor (PAI-1) may be markedly increased in the plasma of patients with endotoxemia and/or renal disease. To investigate renal PAI-1 production during acute endotoxemia, a murine model system was used. Mice were injected with either saline alone or saline containing 50 micrograms endotoxin, and sacrificed 3 hours later and their tissues analyzed for PAI-1 messenger RNA (mRNA) and antigen. Northern blot analysis confirmed that the level of renal PAI-1 mRNA was greatly increased in the endotoxemic mice relative to the saline controls. In situ hybridization was then performed to determine the cellular localization of PAI-1 mRNA within the renal tissues. In the control kidneys, low levels of PAI-1 mRNA were detected in the renal papilla and in the muscular walls of renal arteries. However, in the endotoxemic mice, an intense hybridization signal for PAI-1 mRNA was observed in glomerular and peritubular cells. These cells also stained positively for von Willebrand factor antigen, an endothelial cell-specific marker. The PAI-1 mRNA hybridization signal could further be observed in peritubular endothelial cells in the medulla and in endothelial cells of veins and arteries throughout the kidney. Immunochemical analysis revealed that PAI-1 antigen co-localized to the cytoplasm of cells expressing PAI-1 mRNA. This study provides the first direct evidence that PAI-1 is induced in endothelial cells of the kidney during endotoxemia in vivo and suggests a role for PAI-1 in the pathogenesis of renal disease. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:8424466

Keeton, M.; Eguchi, Y.; Sawdey, M.; Ahn, C.; Loskutoff, D. J.

1993-01-01

322

Selecting "saviour siblings": reconsidering the regulation in Australia of pre-implantation genetic diagnosis in conjunction with tissue typing.  

PubMed

In recent years, pre-implantation genetic diagnosis (PGD) has been developed to enable the selection of a tissue type matched "saviour sibling" for a sick child. This article examines the current regulatory framework governing PGD in Australia. The availability of PGD in Australia to create a saviour sibling depends on the regulation of ART services by each State and Territory. The limitations on the use of PGD vary throughout Australia, according to the level of regulation of ART in each jurisdiction. This article considers the limitations on the use of PGD for tissue typing in Australia and argues that some of these should be removed for a more consistent national approach. In particular, the focus in ART legislation on the "paramount interests" of the child to be born is inappropriate for the application of tissue typing, which necessarily involves the interests of other family members. PMID:17571785

Taylor-Sands, Michelle

2007-05-01

323

An investigation of the use of transmission ultrasound to measure acoustic attenuation changes in thermal therapy.  

PubMed

The potential of using a commercial ultrasound transmission imaging system to quantitatively monitor tissue attenuation changes after thermal therapy was investigated. The ultrasound transmission imaging system used, the AcoustoCam (Imperium Inc., MD) allows ultrasonic images to be captured using principles similar to that of a CCD-type camera that collects light. Ultrasound energy is focused onto a piezoelectric array by an acoustic lens system, creating a gray scale acoustic image. In this work, the pixel values from the acoustic images were assigned acoustic attenuation values by imaging polyacrylamide phantoms of varying known attenuation. After the calibration procedure, data from heated polyacrylamide/bovine serum albumin (BSA) based tissue-mimicking (TM) phantoms and porcine livers were acquired. Samples were heated in water at temperatures of 35, 45, 55, 65, and 75 degrees C for 1 h. Regions of interest were chosen in the images and acoustic attenuation values before and after heating were compared. An increase in ultrasound attenuation was found in phantoms containing BSA and in porcine liver. In the presence of BSA, attenuation in the TM phantom increased by a factor of 1.5, while without BSA no significant changes were observed. The attenuation of the porcine liver increased by up to a factor of 2.4, consistent with previously reported studies. The study demonstrates the feasibility of using a quantitative ultrasound transmission imaging system for monitoring thermal therapy. PMID:16937194

Parmar, Neeta; Kolios, Michael C

2006-07-01

324

Ultrasound RF time series for classification of breast lesions.  

PubMed

This work reports the use of ultrasound radio frequency (RF) time series analysis as a method for ultrasound-based classification of malignant breast lesions. The RF time series method is versatile and requires only a few seconds of raw ultrasound data with no need for additional instrumentation. Using the RF time series features, and a machine learning framework, we have generated malignancy maps, from the estimated cancer likelihood, for decision support in biopsy recommendation. These maps depict the likelihood of malignancy for regions of size 1 mm(2) within the suspicious lesions. We report an area under receiver operating characteristics curve of 0.86 (95% confidence interval [CI]: 0.84%-0.90%) using support vector machines and 0.81 (95% CI: 0.78-0.85) using Random Forests classification algorithms, on 22 subjects with leave-one-subject-out cross-validation. Changing the classification method yielded consistent results which indicates the robustness of this tissue typing method. The findings of this report suggest that ultrasound RF time series, along with the developed machine learning framework, can help in differentiating malignant from benign breast lesions, subsequently reducing the number of unnecessary biopsies after mammography screening. PMID:25350925

Uniyal, Nishant; Eskandari, Hani; Abolmaesumi, Purang; Sojoudi, Samira; Gordon, Paula; Warren, Linda; Rohling, Robert N; Salcudean, Septimiu E; Moradi, Mehdi

2015-02-01

325

Host protective roles of type 2 immunity: Parasite killing and tissue repair, flip sides of the same coin  

PubMed Central

Metazoan parasites typically induce a type 2 immune response, characterized by T helper 2 (Th2) cells that produce the cytokines IL-4, IL-5 and IL-13 among others. The type 2 response is host protective, reducing the number of parasites either through direct killing in the tissues, or expulsion from the intestine. Type 2 immunity also protects the host against damage mediated by these large extracellular parasites as they migrate through the body. At the center of both the innate and adaptive type 2 immune response, is the IL-4R? that mediates many of the key effector functions. Here we highlight the striking overlap between the molecules, cells and pathways that mediate both parasite control and tissue repair. We have proposed that adaptive Th2 immunity evolved out of our innate repair pathways to mediate both accelerated repair and parasite control in the face of continual assault from multicellular pathogens. Type 2 cytokines are involved in many aspects of mammalian physiology independent of helminth infection. Therefore understanding the evolutionary relationship between helminth killing and tissue repair should provide new insight into immune mechanisms of tissue protection in the face of physical injury. PMID:25028340

Allen, Judith E.; Sutherland, Tara E.

2014-01-01

326

5?-Reductase Type 3 Expression in Human Benign and Malignant Tissues: A Comparative Analysis During Prostate Cancer Progression  

PubMed Central

BACKGROUND A third isozyme of human 5?-steroid reductase, 5?-reductase-3, was identified in prostate tissue at the mRNA level. However, the levels of 5?-reductase-3 protein expression and its cellular localization in human tissues remain unknown. METHODS A specific monoclonal antibody was developed, validated, and used to characterize for the first time the expression of 5?-reductase-3 protein in 18 benign and 26 malignant human tissue types using immunostaining analyses. RESULTS AND CONCLUSIONS In benign tissues, 5?-reductase-3 immunostaining was high in conventional androgen-regulated human tissues, such as skeletal muscle and prostate. However, high levels of expression also were observed in non-conventional androgen-regulated tissues, which suggest either multiples target tissues for androgens or different functions of 5?-reductase-3 among human tissues. In malignant tissues, 5?-reductase-3 immunostaining was ubiquitous but particularly over-expressed in some cancers compared to their benign counterparts, which suggests a potential role for 5?-reductase-3 as a biomarker of malignancy. In benign prostate, 5?-reductase-3 immunostaining was localized to basal epithelial cells, with no immunostaining observed in secretory/luminal epithelial cells. In high-grade prostatic intraepithelial neoplasia (HGPIN), 5?-reductase-3 immunostaining was localized in both basal epithelial cells and neoplastic epithelial cells characteristic of HGPIN. In androgen-stimulated and castration-recurrent prostate cancer (CaP), 5?-reductase-3 immunostaining was present in most epithelial cells and at similar levels, and at levels higher than observed in benign prostate. Analyses of expression and functionality of 5?-reductase-3 in human tissues may prove useful for development of treatment for benign prostatic enlargement and prevention and treatment of CaP. PMID:21557268

Godoy, Alejandro; Kawinski, Elzbieta; Li, Yun; Oka, Daizo; Alexiev, Borislav; Azzouni, Faris; Titus, Mark A.; Mohler, James L.

2015-01-01

327

General Ultrasound Imaging  

MedlinePLUS

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

328

Venous Ultrasound (Extremities)  

MedlinePLUS

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

329

Percutaneous tenotomy: Development of a novel, percutaneous, ultrasound-guided needle-cutting technique for division of tendons and other connective tissue structures.  

PubMed

A variety of surgical procedures derive therapeutic benefit from the division of retinacular, ligamentous or tendinous structures. Examples include carpal tunnel release for median nerve impingement, annular pulley release for trigger finger and tendon division for spastic muscular contractures. Here, using an animal cadaveric model, we describe the first steps in determining the feasibility of a novel, percutaneous, ultrasound-guided needle-cutting technique to achieve the same ends. The technique we describe involves the creation of an effective needle tenotomy device via a simple modification to an 18G coaxial, beveled needle. The technique holds promise for the development of a minimally invasive alternative approach that utilises readily available technology and equipment with minimisation of morbidity and cost associated with open procedures. PMID:25088140

Hopkins, James; Sampson, Matthew

2014-06-01

330

A comparative study on collagen type I and hyaluronic acid dependent cell behavior for osteochondral tissue bioprinting.  

PubMed

Bioprinting is a promising technique for engineering composite tissues, such as osteochondral tissues. In this study, as a first step toward bioprinting-based osteochondral tissue regeneration, we systematically examined the behavior of chondrocytes and osteoblasts to hyaluronic acid (HA) and type I collagen (Col-1) hydrogels. First, we demonstrated that cells on hydrogels that were comprised of major native tissue extracellular matrix (ECM) components (i.e. chondrocytes on HA hydrogels and osteoblasts on Col-1 hydrogels) exhibited better proliferation and cell function than cells on non-native ECM hydrogels (i.e., chondrocytes on Col-1 hydrogels and osteoblasts on HA hydrogels). In addition, cells located near their native ECM hydrogels migrated towards them. Finally, we bioprinted three-dimensional (3D) osteochondral tissue-mimetic structures composed of two compartments, osteoblast-encapsulated Col-1 hydrogels and chondrocyte-encapsulated HA hydrogels, and found viability and functions of each cell type were well maintained within the 3D structures up to 14 days in vitro. These results suggest that with proper choice of hydrogel materials, bioprinting-based approaches can be successfully applied for osteochondral tissue regeneration. PMID:24758832

Park, Ju Young; Choi, Jong-Cheol; Shim, Jin-Hyung; Lee, Jung-Seob; Park, Hyoungjun; Kim, Sung Won; Doh, Junsang; Cho, Dong-Woo

2014-09-01

331

Soft tissue perineurioma and other unusual tumors in a patient with neurofibromatosis type 1  

PubMed Central

Perineurioma is a rare benign peripheral nerve sheath tumor featuring perineurial differentiation. Perineurioma occurs sporadically with only one reported case in the setting of neurofibromatosis type 1 (NF-1). We present a 6.7-cm soft tissue perineurioma of the lower leg in a 51-year-old man with proven NF-1. The tumor displayed whorled and fascicular pattern with infiltrative margins and expressed EMA, GLUT-1, claudin-1, and CD34. Electron microscopy confirmed diagnosis. Furthermore, lipomatosis, cutaneous angiomatous nodules, vasculopathy, and iliac spine lesion consistent with non-ossifying fibroma were observed. Tumor DNA revealed no NF2 mutations or chromosomal aberrations but a germline NF1-deletion (c.449_502delTGTT) was detected in his blood sample. His brother displayed neurofibromas, duodenal ganglioneuroma and colonic juvenile polyp, and his mother a neurofibroma, cutaneous squamous cell carcinoma, and jejunal gastrointestinal stromal tumor (GIST); both were affected by NF-1. In conclusion, perineurioma may rarely be NF-1 related and should be included in the spectrum of neoplasms occurring in this disorder. PMID:24294391

Schaefer, Inga-Marie; Ströbel, Philipp; Thiha, Aung; Sohns, Jan Martin; Mühlfeld, Christian; Küffer, Stefan; Felmerer, Gunther; Stepniewski, Adam; Pauli, Silke; Agaimy, Abbas

2013-01-01

332

Adipose tissue distribution in relation to insulin sensitivity and inflammation in Pakistani and Norwegian subjects with type 2 diabetes.  

PubMed

Immigrants from South Asia to Western countries have a high prevalence of type 2 diabetes mellitus (T2DM) associated with obesity. We investigated the relationship between diabetes and adipose tissue distribution in a group of younger T2DM subjects from Norway and Pakistan. Eighteen immigrant Pakistani and 21 Norwegian T2DM subjects (age 29-45, 49% men) were included. They underwent anthropometrical measurements including bioelectrical impedance analysis, CT scans measuring fatty infiltration in liver and adipose and muscle tissue compartments in mid-abdomen and thigh, a euglycemic clamp, and blood samples for serum insulin and plasma glucose, adipokines and inflammation markers. Adipose tissue distribution was similar in Norwegians and Pakistanis. Pakistanis, but not Norwegians, showed a negative correlation between insulin sensitivity and visceral adipose tissue (VAT, rs = - 0.704, p = 0.003). Subcutaneous adipose tissue (SAT) correlated to leptin in both Pakistanis and Norwegians (rs = 0.88, p < 0.001 and 0.67, p = 0.001). SAT also correlated to C-reactive protein (CRP) in the Pakistanis only (rs = 0.55, p = 0.03), and superficial SAT to Interleukin-1 receptor antagonist (IL-1RA) in Norwegians only (rs = 0.47, p = 0.04). In conclusion, despite similar adipose tissue distribution in the two groups Pakistanis were more insulin resistant, with a negative correlation of VAT to insulin sensitivity, not present in Norwegians. The correlation of adipose tissue to Leptin, CRP and IL-1RA showed ethnic differences. PMID:25223599

Wium, Cecilie; Eggesbø, Heidi B; Ueland, Thor; Michelsen, Annika E; Torjesen, Peter A; Aukrust, Pål; Birkeland, Kåre

2014-11-01

333

Treating Cancer with Strong Magnetic Fields and Ultrasound  

E-print Network

It is proposed to treat cancer by the combination of a strong magnetic field with intense ultrasound. At the low electrical conductivity of tissue the magnetic field is not frozen into the tissue, and oscillates against the tissue which is brought into rapid oscillation by the ultrasound. As a result, a rapidly oscillating electric field is induced in the tissue, strong enough to disrupt cancer cell replication. Unlike radio frequency waves, which have been proposed for this purpose, ultrasound can be easily focused onto the regions to be treated. This method has the potential for the complete eradication of the tumor.

Dr. Friedwardt Winterberg

2009-06-03

334

Detection of Curved Robots using 3D Ultrasound  

PubMed Central

Three-dimensional ultrasound can be an effective imaging modality for image-guided interventions since it enables visualization of both the instruments and the tissue. For robotic applications, its realtime frame rates create the potential for image-based instrument tracking and servoing. These capabilities can enable improved instrument visualization, compensation for tissue motion as well as surgical task automation. Continuum robots, whose shape comprises a smooth curve along their length, are well suited for minimally invasive procedures. Existing techniques for ultrasound tracking, however, are limited to straight, laparoscopic-type instruments and thus are not applicable to continuum robot tracking. Toward the goal of developing tracking algorithms for continuum robots, this paper presents a method for detecting a robot comprised of a single constant curvature in a 3D ultrasound volume. Computational efficiency is achieved by decomposing the six-dimensional circle estimation problem into two sequential three-dimensional estimation problems. Simulation and experiment are used to evaluate the proposed method. PMID:22229110

Ren, Hongliang; Vasilyev, Nikolay V.; Dupont, Pierre E.

2011-01-01

335

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

Technology Transfer Automated Retrieval System (TEKTRAN)

Helminths induce potent Th2-type immune responses that can lead to worm expulsion, but it remains undetermined whether components of this response can enhance the wound healing responses elicited as these large multi-cellular parasites traffic thru vital tissues. We used a model of helminth infecti...

336

Evaluation of the safety of four porcine circovirus type 2 tissue homogenate vaccines in a pig bioassay  

Microsoft Academic Search

Ten four-week-old porcine circo virus type 2 (PCV-2) naive piglets were housed individually in a HEP Afiltered isolator and were randomly assigned to one of six treatment groups. Each of the two pigs in groups 1 to 4 received two intramuscular doses of 2 ml of one of four different autogenous tissue homogenate vaccines (THVs) 14 days apart, and the

R. B. Baker; M. Madson; R. Patterson; T. Opriessnig

2009-01-01

337

Transforming growth factor ? 1 and collagen type 1 and III in myocardial tissue in obese and lean Zucker rats  

Microsoft Academic Search

High glucose concentration and insulin resistance states are both associated with a number of metabolic abnormalities in various tissues including myocardium. This study was to determine differences between obese (OZR) and lean (LZR) Zucker rats, which are a model of obesity and mild NIDDM, regarding morphological changes including immunostaining with TGF?1 and two different types of collagen (Col I and

Jorge E. Toblli; Graciela DeRosa; Gabriel Cao; Pablo Piorno

2002-01-01

338

Quantifying skeletal muscle recovery in a rat injury model using ultrasound imaging.  

PubMed

Monitoring skeletal muscle health during recovery or degeneration is of great interest both clinically and in research settings. This type of monitoring requires health measurements be taken at multiple time points. Contraction strength is a commonly used metric for quantifying muscle health, but it requires invasive in vitro or in situ procedures that may further damage the tissue. Ultrasound imaging can be used to visualize muscle damage, and semi-quantitative grading scales have been shown to be effective at characterizing abnormalities. Using an established functional testing procedure in a rat model as a baseline measurement of muscle strength, we show that ultrasound imaging combined with a semi-quantitative grading scale can be used to monitor recovery after contusion injury. Although additional work is needed to refine the imaging and grading procedures, ultrasound promises a fast and non-invasive alternative to functional testing for characterizing skeletal muscle health. PMID:25529138

Leineweber, Matt; Gao, Yingxin

2015-01-21

339

Low dose high frequency ultrasound therapy for stellate ganglion blockade in complex regional pain syndrome type I: a randomised placebo controlled trial  

PubMed Central

Background: We aimed to determine the sympatholytic and clinical effects of low dose high frequency ultrasound (US) applied on stellate ganglion in Complex Regional Pain Syndrome (CRPS) type I patients. Material and method: Fourty-five patients with CRPS type I were randomly allocated into three groups. Pharmacological treatment, transcutaneous electrical nerve stimulation (TENS), contrast bath and exercise were applied to all groups for 20 sessions. In addition to this treatment protocol, low dose high frequency US was applied on stellate ganglion as 0.5 watts/cm2 in group I; 3 watts/cm2 in group II and as placebo in group III. Forty age and sex matched healthy controls were served as controls. Sympathetic skin response (SSR) was used for determining the sympatholytic effects of US. Pain was assessed with visual analog scale (VAS), limitation of total finger flexion was assessed with finger pulp-distal crease distance, muscle strength was assessed with measuring the grip strength, upper extremity disability was assessed with Disability of the Arm, Shoulder and Hand (DASH) scale before and after the treatment. Results: All groups evalueted in terms of VAS score, finger pulp-distal crease distance, grip strength and DASH score after the treatment. The improvements in those parameters were not statistically significant between the groups (P > 0.05). SSR latency was significantly shorter in CRPS patients than controls (P < 0.05). Pre- and post-treatment SSR amplitude and latency values were not different within patient groups (P > 0.05). The differences in pre- and post-treatment SSR amplitude and latency values were not statistically different between patient groups (P > 0.05). Conclusion: Low dose high frequency US applied on stellate ganglion did not make a sympathetic blockade and was not of further benefit for pain, range of motion, grip strength and upper extremity disability in CRPS type I patients. PMID:25664079

Askin, Ayhan; Savas, Serpil; Koyuncuoglu, Hasan Rifat; Baloglu, Hale Hekim; Inci, Mehmet Fatih

2014-01-01

340

Immunohistochemical localization of collagen type XI alpha1 and alpha2 chains in human colon tissue.  

PubMed

In previous studies, collagen XI mRNA has been detected in colon cancer, but its location in human colon tissue has not been determined. The heterotrimeric collagen XI consists of three alpha chains. While it is known that collagen XI plays a regulatory role in collagen fibril formation, its function in the colon is unknown. The characterization of normal human colon tissue will allow a better understanding of the variance of collagen XI in abnormal tissues. Grossly normal and malignant human colon tissue was obtained from pathology archives. Immunohistochemical staining with a 58K Golgi marker and alpha1(XI) and alpha2(XI) antisera was used to specifically locate their presence in normal colon tissue. A comparative bright field microscopic analysis showed the presence of collagen XI in human colon. The juxtanuclear, dot-like collagen XI staining in the Golgi apparatus of goblet cells in normal tissue paralleled the staining of the 58K Golgi marker. Ultra light microscopy verified these results. Staining was also confirmed in malignant colon tissue. This study is the first to show that collagen XI is present in the Golgi apparatus of normal human colon goblet cells and localizes collagen XI in both normal and malignant tissue. Although the function of collagen XI in the colon is unknown, our immunohistochemical characterization provides the foundation for future immunohistopathology studies of the colon. PMID:18040076

Bowen, Kara B; Reimers, Aaron P; Luman, Sarah; Kronz, Joseph D; Fyffe, William E; Oxford, Julia Thom

2008-03-01

341

Wavelet Lifting for Speckle Noise Reduction in Ultrasound Images  

E-print Network

. The efficacy of this filter is demonstrated on both simulated and real medical ultrasound images. The result of research has been done for medical ultrasound speckle de-noising [2][8][10] using different typesWavelet Lifting for Speckle Noise Reduction in Ultrasound Images Yuan Chen, and Amar Raheja

Raheja, Amar

342

Signal acquisition and processing in medical diagnostic ultrasound  

Microsoft Academic Search

As uses for ultrasound increase, so does the need for effective signal processing techniques. In this article we provide an overview of signal acquisition and processing in modern medical ultrasound imaging equipment and present some of the more important concepts in practice today. Images and data types typical of current ultrasound equipment are reviewed; fundamental acoustics and design parameters that

J. U. Quistgaard

1997-01-01

343

Ultrasound echoes as biometric navigators.  

PubMed

We demonstrate a new method of using ultrasound data to achieve prospective motion compensation in MRI, especially for respiratory motion during interventional MRI procedures in moving organs such as the liver. The method relies on fingerprint-like biometrically distinct ultrasound echo patterns produced by different locations in tissue, which are collated with geometrical information from MRI during a training stage to form a mapping table that relates ultrasound measurements to positions. During prospective correction, the system makes frequent ultrasound measurements and uses the map to determine the corresponding position. Results in motorized linear motion phantoms and freely breathing animals indicate that the system performs well. Apparent motion is reduced by up to 97.8%, and motion artifacts are reduced or eliminated in two-dimensional spoiled gradient-echo images. The motion compensation is sufficient to permit MRI thermometry of focused ultrasound heating during respiratory-like motion, with results similar to those obtained in the absence of motion. This new technique may have applications for MRI thermometry and other dynamic imaging in the abdomen during free breathing. PMID:22648783

Schwartz, Benjamin M; McDannold, Nathan J

2013-04-01

344

Spatial coherence in human tissue: implications for imaging and measurement.  

PubMed

The spatial coherence properties of the signal backscattered by human tissue and measured by an ultrasound transducer array are investigated. Fourier acoustics are used to describe the propagation of ultrasound through a model of tissue that includes reverberation and random scattering in the imaging plane. The theoretical development describes how the near-field tissue layer, transducer aperture properties, and reflectivity function at the focus reduce the spatial coherence of the imaging wave measured at the transducer surface. Simulations are used to propagate the acoustic field through a histologically characterized sample of the human abdomen and to validate the theoretical predictions. In vivo measurements performed with a diagnostic ultrasound scanner demonstrate that simulations and theory closely match the measured spatial coherence characteristics in the human body across the transducer array's entire spatial extent. The theoretical framework and simulations are then used to describe the physics of spatial coherence imaging, a type of ultrasound imaging that measures coherence properties instead of echo brightness. The same echo data from an F/2 transducer was used to generate B-mode and short lag spatial coherence images. For an anechoic lesion at the focus, the contrast-to-noise ratio is 1.21 for conventional B-mode imaging and 1.95 for spatial coherence imaging. It is shown that the contrast in spatial coherence imaging depends on the properties of the near-field tissue layer and the backscattering function in the focal plane. PMID:25474774

Pinton, Gianmarco; Trahey, Gregg; Dahl, Jeremy

2014-12-01

345

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

346

[The ultrasound semiotics of uncomplicated wound healing after inguinal mesh plastics].  

PubMed

Dynamic ultrasound (US) investigation was performed in 89 patients operated on inguinal hernia with the use of meshes of various type. The US scanning proved to be a highly informative means of visualization, allowing the objective postoperative assessment of muscular and aponeurotic structures as well as the implant form and position. The study showed, that the mesh implantation was always accompanied by the exudative tissue reaction, which was determined by the physico-chemical characteristics of the implant. PMID:23257698

Kharitonov, S V; Ziniakova, M V

2012-01-01

347

Ultrasound Molecular Imaging of Cardiovascular Disease  

Microsoft Academic Search

Molecular imaging with ultrasound contrast agents relies on the detection of microbubbles within diseased tissue. Microbubbles\\u000a produce an acoustic signal owing to their resonant properties in an ultrasound field. Microbubble targeting is accomplished\\u000a by either manipulating the microbubble shell for attachment of microbubbles to activated leukocytes, or by conjugation of\\u000a disease-specific ligands to the microbubble surface. Inflammation, angiogenesis, and thrombus

Beat A. Kaufmann

2010-01-01

348

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

NASA Astrophysics Data System (ADS)

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

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

1999-05-01

349

Methylation quantitative trait loci (meQTLs) are consistently detected across ancestry, developmental stage, and tissue type  

PubMed Central

Background Individual genotypes at specific loci can result in different patterns of DNA methylation. These methylation quantitative trait loci (meQTLs) influence methylation across extended genomic regions and may underlie direct SNP associations or gene-environment interactions. We hypothesized that the detection of meQTLs varies with ancestral population, developmental stage, and tissue type. We explored this by analyzing seven datasets that varied by ancestry (African American vs. Caucasian), developmental stage (neonate vs. adult), and tissue type (blood vs. four regions of postmortem brain) with genome-wide DNA methylation and SNP data. We tested for meQTLs by constructing linear regression models of methylation levels at each CpG site on SNP genotypes within 50 kb under an additive model controlling for multiple tests. Results Most meQTLs mapped to intronic regions, although a limited number appeared to occur in synonymous or nonsynonymous coding SNPs. We saw significant overlap of meQTLs between ancestral groups, developmental stages, and tissue types, with the highest rates of overlap within the four brain regions. Compared with a random group of SNPs with comparable frequencies, meQTLs were more likely to be 1) represented among the most associated SNPs in the WTCCC bipolar disorder results and 2) located in microRNA binding sites. Conclusions These data give us insight into how SNPs impact gene regulation and support the notion that peripheral blood may be a reliable correlate of physiological processes in other tissues. PMID:24555763

2014-01-01

350

Ultrasound annual, 1986  

SciTech Connect

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

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

1986-01-01

351

Glycoproteomics approach for identifying Glycobiomarker candidate molecules for tissue type classification of non-small cell lung carcinoma.  

PubMed

Histopathological classification of lung cancer has important implications in the application of clinical practice guidelines and the prediction of patient prognosis. Thus, we focused on discovering glycobiomarker candidates to classify the types of lung cancer tissue. First, we performed lectin microarray analysis of lung cancer tissue specimens and cell lines and identified Aleuria aurantia lectin (AAL), Hippeastrum hybrid lectin (HHL), and Concanavalia ensiformis agglutinin (ConA) as lectin probes specific to non-small cell lung carcinoma (NSCLC). LC-MS-based analysis was performed for the comprehensive identification of glycoproteins and N-linked glycosylation sites using lectin affinity capture of NSCLC-specific glycoforms of glycoproteins. This analysis identified 1092 AAL-bound glycoproteins (316 gene symbols) and 948 HHL/ConA-bound glycoproteins (279 gene symbols). The lectin microarray-assisted verification using 15 lung cancer cell lines revealed the NSCLC-specific expression of fibronectin. The glycosylation profiling of fibronectin indicated that the peanut agglutinin (PNA) signal appeared to differentiate two NSCLC types, adenocarcinoma and large cell carcinoma, whereas the protein expression level was similar between these types. Our glycoproteomics approach together with the concurrent use of an antibody and lectin is applicable to the quantitative and qualitative monitoring of variations in glycosylation of fibronectin specific to certain types of lung cancer tissue. PMID:25244057

Hirao, Yoshitoshi; Matsuzaki, Hideki; Iwaki, Jun; Kuno, Atsushi; Kaji, Hiroyuki; Ohkura, Takashi; Togayachi, Akira; Abe, Minako; Nomura, Masaharu; Noguchi, Masayuki; Ikehara, Yuzuru; Narimatsu, Hisashi

2014-11-01

352

TGF ?1 and PDGF AA override Collagen type I inhibition of proliferation in human liver connective tissue cells  

PubMed Central

Background A marked expansion of the connective tissue population and an abnormal deposition of extracellular matrix proteins are hallmarks of chronic and acute injuries to liver tissue. Liver connective tissue cells, also called stellate cells, derived from fibrotic liver have been thoroughly characterized and correspond phenotypically to myofibroblasts. They are thought to derive from fat-storing Ito cells in the perisinusoidal space and acquire a contractile phenotype when activated by tissue injury. In the last few years it has become evident that several peptide growth factors such as PDGF AA and TGF-? are involved in the development of fibrosis by modulating myofibroblast proliferation and collagen secretion. The fact that during the development of chronic fibrosis there is concomitant deposition of collagen, a known inhibitory factor, and sustained cell proliferation, raises the possibility that stellate cells from chronic liver fibrosis patients fail to respond to normal physiologic controls. Methods In this study we address whether cells from fibrotic liver patients respond to normal controls of proliferation. We compared cell proliferation of primary human liver connective tissue cells (LCTC) from patients with liver fibrosis and skin fibroblasts (SF) in the presence of collagens type I and IV; TGF-?, PDGF AA and combinations of collagen type I and TGF-? or PDGF AA. Results Our results indicate that despite displaying normal contact and collagen-induced inhibition of proliferation LCTC respond more vigorously to lower concentrations of PDGF AA. In addition, we show that collagen type I synergizes with growth factors to promote mitogenesis of LCTC but not SF. Conclusions The synergistic interaction of growth factors and extracellular matrix proteins may underlie the development of chronic liver fibrosis. PMID:15579200

Geremias, Alvaro T; Carvalho, Marcelo A; Borojevic, Radovan; Monteiro, Alvaro NA

2004-01-01

353

PHOTOACOUSTIC IMAGING AND HIGH INTENSITY FOCUSED ULTRASOUND IN BIOMEDICAL APPLICATIONS  

E-print Network

with the effects of high intensity ultrasound for therapy rather than diagnosis. High intensity focused ultrasound (HIFU) is one of the non-invasive methods used primarily to treat abnormal tissue thermally through hyperthermia (27-29). During HIFU treatment.... With imaging systems such as ultrasound imaging and magnetic resonance imaging (MRI), the use of HIFU has been extended. 4 Since the treatment of bladder cancers with HIFU has been attempted, HIFU has been used as an effective treatment for ablation...

Jo, Janggu

2014-08-31

354

Ehlers-Danlos syndrome type VIII is clinically heterogeneous disorder associated primarily with periodontal disease, and variable connective tissue features.  

PubMed

Ehlers-Danlos syndrome (EDS) type VIII (periodontitis type) is a distinct form of EDS characterized by periodontal disease leading to precocious dental loss and a spectrum of joint and skin manifestations. EDS type VIII is transmitted in an autosomal dominant pattern; however, the mutated gene has not been identified. There are insufficient data on the spectrum of clinical manifestations and natural history of the disorder, and only a limited number of patients and pedigrees with this condition have been reported. We present a four-generation EDS type VIII kindred and show that EDS VIII is clinically variable and although some cases lack the associated skin and joint manifestations, microscopic evidence of collagen disorganization is detectable.We further propose that the diagnosis of EDS type VIII should be considered in familial forms of periodontitis, even when the associated skin and joint manifestations are unconvincing for the diagnosis of a connective tissue disorder. This novel observation highlights the uncertainty of using connective tissue signs in clinical practice to diagnose EDS type VIII. PMID:22739343

Reinstein, Eyal; DeLozier, Celia Dawn; Simon, Ziv; Bannykh, Serguei; Rimoin, David L; Curry, Cynthia J

2013-02-01

355

Ehlers–Danlos syndrome type VIII is clinically heterogeneous disorder associated primarily with periodontal disease, and variable connective tissue features  

PubMed Central

Ehlers–Danlos syndrome (EDS) type VIII (periodontitis type) is a distinct form of EDS characterized by periodontal disease leading to precocious dental loss and a spectrum of joint and skin manifestations. EDS type VIII is transmitted in an autosomal dominant pattern; however, the mutated gene has not been identified. There are insufficient data on the spectrum of clinical manifestations and natural history of the disorder, and only a limited number of patients and pedigrees with this condition have been reported. We present a four-generation EDS type VIII kindred and show that EDS VIII is clinically variable and although some cases lack the associated skin and joint manifestations, microscopic evidence of collagen disorganization is detectable. We further propose that the diagnosis of EDS type VIII should be considered in familial forms of periodontitis, even when the associated skin and joint manifestations are unconvincing for the diagnosis of a connective tissue disorder. This novel observation highlights the uncertainty of using connective tissue signs in clinical practice to diagnose EDS type VIII. PMID:22739343

Reinstein, Eyal; DeLozier, Celia Dawn; Simon, Ziv; Bannykh, Serguei; Rimoin, David L; Curry, Cynthia J

2013-01-01

356

Patterns of regulatory activity across diverse human cell types predict tissue identity, transcription factor binding, and long-range interactions.  

PubMed

Regulatory elements recruit transcription factors that modulate gene expression distinctly across cell types, but the relationships among these remains elusive. To address this, we analyzed matched DNase-seq and gene expression data for 112 human samples representing 72 cell types. We first defined more than 1800 clusters of DNase I hypersensitive sites (DHSs) with similar tissue specificity of DNase-seq signal patterns. We then used these to uncover distinct associations between DHSs and promoters, CpG islands, conserved elements, and transcription factor motif enrichment. Motif analysis within clusters identified known and novel motifs in cell-type-specific and ubiquitous regulatory elements and supports a role for AP-1 regulating open chromatin. We developed a classifier that accurately predicts cell-type lineage based on only 43 DHSs and evaluated the tissue of origin for cancer cell types. A similar classifier identified three sex-specific loci on the X chromosome, including the XIST lincRNA locus. By correlating DNase I signal and gene expression, we predicted regulated genes for more than 500K DHSs. Finally, we introduce a web resource to enable researchers to use these results to explore these regulatory patterns and better understand how expression is modulated within and across human cell types. PMID:23482648

Sheffield, Nathan C; Thurman, Robert E; Song, Lingyun; Safi, Alexias; Stamatoyannopoulos, John A; Lenhard, Boris; Crawford, Gregory E; Furey, Terrence S

2013-05-01

357

Patterns of regulatory activity across diverse human cell types predict tissue identity, transcription factor binding, and long-range interactions  

PubMed Central

Regulatory elements recruit transcription factors that modulate gene expression distinctly across cell types, but the relationships among these remains elusive. To address this, we analyzed matched DNase-seq and gene expression data for 112 human samples representing 72 cell types. We first defined more than 1800 clusters of DNase I hypersensitive sites (DHSs) with similar tissue specificity of DNase-seq signal patterns. We then used these to uncover distinct associations between DHSs and promoters, CpG islands, conserved elements, and transcription factor motif enrichment. Motif analysis within clusters identified known and novel motifs in cell-type-specific and ubiquitous regulatory elements and supports a role for AP-1 regulating open chromatin. We developed a classifier that accurately predicts cell-type lineage based on only 43 DHSs and evaluated the tissue of origin for cancer cell types. A similar classifier identified three sex-specific loci on the X chromosome, including the XIST lincRNA locus. By correlating DNase I signal and gene expression, we predicted regulated genes for more than 500K DHSs. Finally, we introduce a web resource to enable researchers to use these results to explore these regulatory patterns and better understand how expression is modulated within and across human cell types. PMID:23482648

Sheffield, Nathan C.; Thurman, Robert E.; Song, Lingyun; Safi, Alexias; Stamatoyannopoulos, John A.; Lenhard, Boris; Crawford, Gregory E.; Furey, Terrence S.

2013-01-01

358

Role of structural anisotropy of biological tissues in poroelastic wave propagation  

PubMed Central

Ultrasound waves have a broad range of clinical applications as a non-destructive testing approach in imaging and in the diagnoses of medical conditions. Generally, biological tissues are modeled as an homogenized equivalent medium with an apparent density through which a single wave propagates. Only the first wave arriving at the ultrasound probe is used for the measurement of the speed of sound. However, the existence of a second wave in tissues such as cancellous bone has been reported and its existence is an unequivocal signature of Biot type poroelastic media. To account for the fact that ultrasound is sensitive to microarchitecture as well as density, a fabric-dependent anisotropic poroelastic ultrasound (PEU) propagation theory was recently developed. Key to this development was the inclusion of the fabric tensor - a quantitative stereological measure of the degree of structural anisotropy of bone - into the linear poroelasticity theory. In the present study, this framework is extended to the propagation of waves in several soft and hard tissues. It was found that collagen fibers in soft tissues and the mineralized matrix in hard tissues are responsible for the anisotropy of the solid tissue constituent through the fabric tensor in the model. PMID:22162897

Cardoso, Luis; Cowin, Stephen C.

2011-01-01

359

Adipose Tissue-Derived Stem Cells Ameliorate Diabetic Bladder Dysfunction in a Type II Diabetic Rat Model  

PubMed Central

Diabetes mellitus is associated with a broad constellation of voiding complaints that are often multifactorial and resistant to currently available therapies. The leading causes of diabetic bladder dysfunction (DBD) include alterations in the bladder smooth muscle, neuronal degeneration, and urothelial dysfunction. Adipose tissue-derived stem cells (ADSCs), a type of mesenchymal stromal cells, have shown promise as a novel tissue regenerative technique that may have utility in DBD. The aim of this study is to determine the efficacy and mechanism by which ADSCs may ameliorate DBD in rats fed a high-fat diet and treated with low-dose streptozotocin to induce type II diabetes. Improved voiding function was noted in ADSCs-treated rats as compared with phosphate-buffered saline-treated rats. Though some ADSCs differentiated into smooth muscle cells, paracrine pathway seems to play a main role in this process, thus resulting in reduction of apoptosis and preservation of “suburothelial capillaries network.” PMID:22008016

Zhang, Haiyang; Qiu, Xuefeng; Shindel, Alan W.; Ning, Hongxiu; Ferretti, Ludovic; Jin, Xunbo; Lin, Guiting; Lin, Ching-Shwun

2012-01-01

360

Liver-Resident Macrophage Necroptosis Orchestrates Type 1 Microbicidal Inflammation and Type-2-Mediated Tissue Repair during Bacterial Infection.  

PubMed

Kupffer cells, the phagocytes of fetal origin that line the liver sinusoids, are key contributors of host defense against enteroinvasive bacteria. Here, we found that infection by Listeria monocytogenes induced the early necroptotic death of Kupffer cells, which was followed by monocyte recruitment and an anti-bacterial type 1 inflammatory response. Kupffer cell death also triggered a type 2 response that involved the hepatocyte-derived alarmin interleukin-33 (IL-33) and basophil-derived interleukin-4 (IL-4). This led to the alternative activation of the monocyte-derived macrophages recruited to the liver, which thereby replaced ablated Kupffer cells and restored liver homeostasis. Kupffer cell death is therefore a key signal orchestrating type 1 microbicidal inflammation and type-2-mediated liver repair upon infection. This indicates that beyond the classical dichotomy of type 1 and type 2 responses, these responses can develop sequentially in the context of a bacterial infection and act interdependently, orchestrating liver immune responses and return to homeostasis, respectively. PMID:25577440

Blériot, Camille; Dupuis, Théo; Jouvion, Grégory; Eberl, Gérard; Disson, Olivier; Lecuit, Marc

2015-01-20

361

Ultrasound-assisted dispersive liquid-liquid microextraction plus simultaneous silylation for rapid determination of salicylate and benzophenone-type ultraviolet filters in aqueous samples.  

PubMed

A rapid procedure, using minimal amounts of solvent, for the reliable determination of five salicylate and benzophenone-type ultraviolet (UV) filters: ethylhexyl salicylate (EHS), 3,3,5-trimethyl-cyclohexyl salicylate (HMS), 2-hydroxy-4-methoxybenzophenone (BP-3), 2,4-dihydroxy-benzophenone (BP-1) and 2,2'-dihydroxy-4-methoxybenzophenone (BP-8), in aqueous samples is described. The method involves an ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) plus simultaneous silylation prior to their determination by gas chromatography-mass spectrometry (GC-MS). The parameters affecting the extraction and derivatization efficiency of the target UV filters from aqueous samples were systematically investigated and the conditions optimized. The optimal silylation and extraction conditions involved the rapid injection of a mixture of 750?L of acetone (as a dispersant), 15?L of tetrachloroethylene (as an extractant), and 20?L of BSTFA (as a derivatizing agent) into a 10-mL volume of aqueous samples (pH 7.0) containing 0.5g of sodium chloride in a glass tube with a conical bottom. After ultrasonication for 2.0min and centrifugation at 5000rpm (10min), the sedimented phase 5.0?L was directly introduced into the GC-MS. The limits of quantitation (LOQs) were less than 6ng/L. The precision for these analytes, as indicated by the relative standard deviations (RSDs), was less than 9% for both intra- and inter-day analysis. Accuracy, expressed as the mean extraction recovery, was between 74 and 92%. The method was then applied to environmental aqueous samples, using a standard addition method, showing the occurrence of BP-3 in samples of both river water and municipal wastewater treatment plant (MWTP) effluents. PMID:23831000

Wu, Jen-Wen; Chen, Hsin-Chang; Ding, Wang-Hsien

2013-08-01

362

Ultrasound analysis of gray-scale median value of carotid plaques is a useful reference index for cerebro-cardiovascular events in patients with type 2 diabetes  

PubMed Central

Aims/Introduction Measurements of plaque echogenicity, the gray-scale median (GSM), were shown to correlate inversely with risk factors for cerebro-cardiovascular disease (CVD). The eicosapentaenoic acid (EPA)/arachidonic acid (AA) ratio is a potential predictor of CVD risk. In the present study, we assessed the usefulness of carotid plaque GSM values and EPA/AA ratios in atherosclerotic diabetics. Materials and Methods A total of 84 type 2 diabetics with carotid artery plaques were enrolled. On admission, platelet aggregation and lipid profiles, including EPA and AA, were examined. Using ultrasound, mean intima media thickness and plaque score were measured in carotid arteries. Plaque echogenicity was evaluated using computer-assisted quantification of GSM. The patients were then further observed for approximately 3 years. Results Gray-scale median was found to be a good marker of CVD events. On multivariate logistic regression analysis, GSM <32 and plaque score ?5 were significantly associated with past history and onset of CVD during the follow-up period, the odds ratios being 7.730 (P = 0.014) and 4.601 (P = 0.046), respectively. EPA/AA showed a significant correlation with GSM (P = 0.012) and high-density lipoprotein cholesterol (P = 0.039), and an inverse correlation with platelet aggregation (P = 0.046) and triglyceride (P = 0.020). Although most patients with CVD had both low GSM and low EPA/AA values, an association of EPA/AA with CVD events could not be statistically confirmed. Conclusions The present results suggest the GSM value to be useful as a reference index for CVD events in high-risk atherosclerotic diabetics. Associations of the EPA/AA ratio with known CVD risk factors warrant a larger and more extensive study to show the usefulness of this parameter.

Ariyoshi, Kyoko; Okuya, Shigeru; Kunitsugu, Ichiro; Matsunaga, Kimie; Nagao, Yuko; Nomiyama, Ryuta; Takeda, Komei; Tanizawa, Yukio

2015-01-01

363

Comparative accuracy of B-type natriuretic peptide and tissue Doppler echocardiography in the diagnosis of congestive heart failure  

Microsoft Academic Search

B-type natriuretic peptide (BNP) and early diastolic transmitral velocity\\/tissue Doppler mitral annular velocity (E\\/Ea) both estimate left ventricular filling pressure, but have not been compared in the diagnosis of congestive heart failure (CHF). One hundred twenty-two hospital inpatients with suspected CHF underwent simultaneous clinical examination, BNP measurement, and comprehensive echo-Doppler examination. The accuracy of BNP and echocardiography was compared with

Hisham Dokainish; William A Zoghbi; Nasser M Lakkis; Miguel A Quinones; Sherif F Nagueh

2004-01-01

364

Interleukin 1 and lipopolysaccharide induce an inhibitor of tissue-type plasminogen activator in vivo and in cultured endothelial cells  

Microsoft Academic Search

In the physiological process of fibrinolysis, the enzymes now considered to be of prime importance are plasminogen and tissue-type plasminogen activator (t-PA) 1 (1). Recently, evidence has been presented (1) for the occurrence in plasma of a fast-acting PA inhibitor. Together with the fast-acting plasmin inhibitor a2-antiplasmin, the PA-inhibitor determines to a great extent the expression of the fibrinolytic potential

J. J. Emeis; T. KOOISTRA

1986-01-01

365

Vampire Bat Salivary Plasminogen Activator (Desmoteplase) Inhibits Tissue-Type Plasminogen Activator-Induced Potentiation of Excitotoxic Injury  

Microsoft Academic Search

Background and Purpose—In contrast to tissue-type plasminogen activator (tPA), vampire bat (Desmodus rotundus) salivary plasminogen activator (desmoteplase (DSPA)) does not promote excitotoxic injury when injected directly into the brain. We have compared the excitotoxic effects of intravenously delivered tPA and DSPA and determined whether DSPA can antagonize the neurotoxic and calcium enhancing effects of tPA. Methods—The brain striatal region of

Courtney Reddrop; Randal X. Moldrich; Philip M. Beart; Mark Farso; Gabriel T. Liberatore; David W. Howells; Karl-Uwe Petersen; Wolf-Dieter Schleuning; Robert L. Medcalf

2010-01-01

366

Surface modification of nanofibrous polycaprolactone/gelatin composite scaffold by collagen type I grafting for skin tissue engineering.  

PubMed

In the present study, a tri-polymer polycaprolactone (PCL)/gelatin/collagen type I composite nanofibrous scaffold has been fabricated by electrospinning for skin tissue engineering and wound healing applications. Firstly, PCL/gelatin nanofibrous scaffold was fabricated by electrospinning using a low cost solvent mixture [chloroform/methanol for PCL and acetic acid (80% v/v) for gelatin], and then the nanofibrous PCL/gelatin scaffold was modified by collagen type I (0.2-1.5wt.%) grafting. Morphology of the collagen type I-modified PCL/gelatin composite scaffold that was analyzed by field emission scanning electron microscopy (FE-SEM), showed that the fiber diameter was increased and pore size was decreased by increasing the concentration of collagen type I. Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric (TG) analysis indicated the surface modification of PCL/gelatin scaffold by collagen type I immobilization on the surface of the scaffold. MTT assay demonstrated the viability and high proliferation rate of L929 mouse fibroblast cells on the collagen type I-modified composite scaffold. FE-SEM analysis of cell-scaffold construct illustrated the cell adhesion of L929 mouse fibroblasts on the surface of scaffold. Characteristic cell morphology of L929 was also observed on the nanofiber mesh of the collagen type I-modified scaffold. Above results suggest that the collagen type I-modified PCL/gelatin scaffold was successful in maintaining characteristic shape of fibroblasts, besides good cell proliferation. Therefore, the fibroblast seeded PCL/gelatin/collagen type I composite nanofibrous scaffold might be a potential candidate for wound healing and skin tissue engineering applications. PMID:24268275

Gautam, Sneh; Chou, Chia-Fu; Dinda, Amit K; Potdar, Pravin D; Mishra, Narayan C

2014-01-01

367

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

368

Association between Tissue Characteristics of Coronary Plaque and Distal Embolization after Coronary Intervention in Acute Coronary Syndrome Patients: Insights from a Meta-Analysis of Virtual Histology-Intravascular Ultrasound Studies  

PubMed Central

Background and Objectives The predictive value of plaque characteristics assessed by virtual histology-intravascular ultrasound (VH-IVUS) including fibrous tissue (FT), fibrofatty (FF), necrotic core (NC) and dense calcium (DC) in identifying distal embolization after percutaneous coronary intervention (PCI) is still controversial. We performed a systematic review and meta-analysis to summarize the association of pre-PCI plaque composition and post-PCI distal embolization in acute coronary syndrome patients. Methods Studies were identified in PubMed, OVID, EMBASE, the Cochrane Library, the Current Controlled Trials Register, reviews, and reference lists of relevant articles. A meta-analysis using both fixed and random effects models with assessment of study heterogeneity and publication bias was performed. Results Of the 388 articles screened, 10 studies with a total of 872 subjects (199 with distal embolization and 673 with normal flow) met the eligibility of our study. Compared with normal flow groups, significant higher absolute volume of NC [weighted mean differences (WMD): 5.79 mm3, 95% CI: 3.02 to 8.55 mm3; p<0.001] and DC (WMD: 2.55 mm3, 95% CI: 0.22 to 4.88 mm3; p?=?0.03) were found in acute coronary syndrome patients with distal embolization. Further subgroup analysis demonstrated that the predictive value of tissue characteristics in determining distal embolization was correlated to clinical scenario of the patients, definition of distal embolization, and whether the percutaneous aspiration thrombectomy was applied. Conclusion Our study that pooled current evidence showed that plaque components were closely related to the distal embolization after PCI, especially the absolute volume of NC and DC, supporting further studies with larger sample size and high-methodological quality. PMID:25375841

Yang, Fan; Kong, Lingcong; Zhao, Yichao; Gao, Lingchen; Wang, Wei; Xu, Rende; Ge, Heng; Jiang, Meng; Pu, Jun; He, Ben

2014-01-01

369

Evaluation of ultrasound-assisted extraction as sample pre-treatment for quantitative determination of rare earth elements in marine biological tissues by inductively coupled plasma-mass spectrometry.  

PubMed

In this work, the determination of rare earth elements (REEs), i.e. Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu in marine biological tissues by inductively coupled-mass spectrometry (ICP-MS) after a sample preparation method based on ultrasound-assisted extraction (UAE) is described. The suitability of the extracts for ICP-MS measurements was evaluated. For that, studies were focused on the following issues: (i) use of clean up of extracts with a C18 cartridge for non-polar solid phase extraction; (ii) use of different internal standards; (iii) signal drift caused by changes in the nebulization efficiency and salt deposition on the cones during the analysis. The signal drift produced by direct introduction of biological extracts in the instrument was evaluated using a calibration verification standard for bracketing (standard-sample bracketing, SSB) and cumulative sum (CUSUM) control charts. Parameters influencing extraction such as extractant composition, mass-to-volume ratio, particle size, sonication time and sonication amplitude were optimized. Diluted single acids (HNO(3) and HCl) and mixtures (HNO(3)+HCl) were evaluated for improving the extraction efficiency. Quantitative recoveries for REEs were achieved using 5 mL of 3% (v/v) HNO(3)+2% (v/v) HCl, particle size <200 ?m, 3 min of sonication time and 50% of sonication amplitude. Precision, expressed as relative standard deviation from three independent extractions, ranged from 0.1 to 8%. In general, LODs were improved by a factor of 5 in comparison with those obtained after microwave-assisted digestion (MAD). The accuracy of the method was evaluated using the CRM BCR-668 (mussel tissue). Different seafood samples of common consumption were analyzed by ICP-MS after UAE and MAD. PMID:20951856

Costas, M; Lavilla, I; Gil, S; Pena, F; de la Calle, I; Cabaleiro, N; Bendicho, C

2010-10-29

370

Noninvasive Multimodal Evaluation of Bioengineered Cartilage Constructs Combining Time-Resolved Fluorescence and Ultrasound Imaging  

PubMed Central

A multimodal diagnostic system that integrates time-resolved fluorescence spectroscopy, fluorescence lifetime imaging microscopy, and ultrasound backscatter microscopy is evaluated here as a potential tool for assessing changes in engineered tissue composition and microstructure nondestructively and noninvasively. The development of techniques capable of monitoring the quality of engineered tissue, determined by extracellular matrix (ECM) content, before implantation would alleviate the need for destructive assays over multiple time points and advance the widespread development and clinical application of engineered tissues. Using a prototype system combining time-resolved fluorescence spectroscopy, FLIM, and UBM, we measured changes in ECM content occurring during chondrogenic differentiation of equine adipose stem cells on 3D biodegradable matrices. The optical and ultrasound results were validated against those acquired via conventional techniques, including collagen II immunohistochemistry, picrosirius red staining, and measurement of construct stiffness. Current results confirm the ability of this multimodal approach to follow the progression of tissue maturation along the chondrogenic lineage by monitoring ECM production (namely, collagen type II) and by detecting resulting changes in mechanical properties of tissue constructs. Although this study was directed toward monitoring chondrogenic tissue maturation, these data demonstrate the feasibility of this approach for multiple applications toward engineering other tissues, including bone and vascular grafts. PMID:21303258

Fite, Brett Z.; Decaris, Martin; Sun, Yinghua; Sun, Yang; Lam, Adrian; Ho, Clark K.L.

2011-01-01

371

Antithrombotic effect of tissue and plasma type angiotensin converting enzyme inhibitors in experimental thrombosis in rats.  

PubMed

This study compared the antithrombotic effect of plasma angiotensin converting enzyme inhibitors (ACE-Is): captopril (CAP), enalapril (ENA) and tissue ACE-Is: perindopril (PER), quinapril (QUIN) in experimental venous and arterial thrombosis. Normotensive Wistar rats were treated p.o. with CAP (75 mg/kg), ENA (20 mg/kg), PER (2 mg/kg) and QUIN (3 mg/kg) for 10 days. The influence of ACE-Is on coagulation and fibrinolytic systems as well as platelet function was evaluated. The hypotensive effect of ACE-Is was equal in all groups. QUIN maintained the final carotid blood flow at the highest value in comparison to PER and plasma ACE-Is. The arterial thrombus weight was reduced in PER and QUIN groups while venous thrombus weight was also reduced after CAP. Tissue and plasma ACE-Is caused the inhibition of platelet adhesion and aggregation. A reduction of fibrin generation, prolongation of prothrombin time (PT), activated partial thromboplastin time (APTT) and shortening of euglobulin clot lysis time (ECLT) were observed after PER and QUIN treatment. In conclusion, given in equipotent hypotensive doses, tissue ACE-Is exerted more pronounced antithrombotic effect than plasma ACE-Is in experimental thrombosis. The differences between tissue and plasma ACE-Is in terms of their more pronounced inhibition of experimental thrombosis may be related to the intensified activation of fibrinolysis and inhibition of coagulation. PMID:16845228

Wojewódzka-Zelezniakowicz, M; Chabielska, E; Mogielnicki, A; Kramkowski, K; Karp, A; Opadczuk, A; Domaniewski, T; Malinowska-Zaprza?ka, M; Buczko, W

2006-06-01

372

Different types of connective tissue alterations associated with cervical artery dissections  

Microsoft Academic Search

This study describes the technical handling and the diagnostic evaluation of skin biopsies in order to standardize the assessment of the delicate morphologic abnormalities that are found in patients with spontaneous cervical artery dissections (sCAD). Skin biopsies from 126 patients with sCAD and from 29 healthy relatives were analyzed. The morphology of the connective tissue was normal in 54 patients

Ingrid Hausser; Uta Müller; Stefan Engelter; Philippe Lyrer; Alessandro Pezzini; Alessandro Padovani; Birgit Moormann; Otto Busse; Ralf Weber; Tobias Brandt; Caspar Grond-Ginsbach

2004-01-01

373

Circulating lupus type anticoagulant and pulmonary hypertension associated with mixed connective tissue disease  

Microsoft Academic Search

Summary We report the case of a young woman, with mixed connective tissue disease (MCTD), associated with disabling pulmonary hypertension and presence of the “lupus anticoagulant”. The “lupus anticoagulant”, an antibody directed against phospholipid components, was linked in our patient to extensive thrombophlebitis and premature labor. Raynaud's phenomenon progressed towards finger necrosis in spite of optimal vasodilating treatment. The part

P. Hainaut; E. Lavenne; J. M. Magy; E. G. Lebacq

1986-01-01

374

Bruising profile of fresh apples associated with tissue type and structure. Applied Engineering in Agriculture  

Technology Transfer Automated Retrieval System (TEKTRAN)

It is important to understand how apples bruise in order to prevent or reduce bruising. Tissue from ‘Golden Delicious’ apples was analyzed to determine the bruising mechanism at different maturity levels. Bruising was induced by an artificial finger attached to an Instron machine applying an exter...

375

High-resolution imaging using ultrasound-modulated optical tomography  

Microsoft Academic Search

We present an implementation of ultrasound-modulated optical tomography that has the potential to provide high resolution images of tissue structures at a penetration depth of several millimeters. Light and pulsed ultrasound are focused on an approximately 100 mum wide area below the sample surface. With this configuration, the length of the ultrasonic pulses determines the axial resolution, and the lateral

Sava Sakadzic; Konstantin Maslov; Jun Li; Vikram K. Kinra; Lihong V. Wang

2004-01-01

376

Sonochemistry and Sonoluminescence in Simulated Ultrasound-assisted Lipoplasty Environment  

Microsoft Academic Search

Background: The issue of safety has arisen with the advent of high-intensity ultrasound energy (HIUE) in ultrasound-assisted lipoplasty (UAL). HIUE has been used in the last 3 decades in a variety of surgical procedures, but scientific data are lacking with regard to biologic interactions. We hypothesize that infiltration of tissue with an aqueous solution and exposure to HIUE as practiced

Moris Topaz; Aharon Gedanken; Yuri Koltypin; Menachem Motiei; Matthew B. Grisham; Seth J. Putterman; Keith R. Weninger

1999-01-01

377

A constrained adaptive beamformer for medical ultrasound: initial results  

Microsoft Academic Search

Adaptive beamforming has been widely used as a way to improve image quality in medical ultrasound applications by correcting phase and amplitude aberration errors resulting from tissue inhomogeneity. A less-studied concern in ultrasound beamforming is the deleterious contribution of bright off-axis targets. This paper describes a new approach, the constrained adaptive beamformer (CAB), which builds on classic array processing methods

J. A. Mann; W. F. Walker

2002-01-01

378

Medical ultrasound - From inner space to outer space  

NASA Technical Reports Server (NTRS)

During the last decade, medical ultrasound has rapidly become a widely accepted imaging modality used in many medical specialties. It has the advantages that it is noninvasive, does not use ionizing radiation, is relatively inexpensive and is easy to use. Future trends in ultrasound include expanded areas of use, advanced signal processing and digital image analysis including tissue characterization and three-dimensional reconstructions.

Rooney, J. A.

1984-01-01

379

Passive imaging of cavitational acoustic emissions with ultrasound arrays  

E-print Network

bubble activity plays a role in ultrasound ablation, monitoring cavitation may assist in therapy guidance therapies including shock-wave lithotripsy [1], thrombolysis [2], targeted drug delivery [3], and thermal ablation [4]. During ultrasound ablation, cavitation results in enhanced tissue heating [5], but also

Mast, T. Douglas

380

Fuzzy discrimination of MCC and fat in breast transmissive ultrasound CT images  

Microsoft Academic Search

So far, hardly ever has breast cancer been diagnosed in its early stages using non-invasive detectors. Application of ultrasound as a safe imaging system has also failed due to the similar reflectivity indices of fat and malignant tissue. Here a new equipment called Intelligent Ultrasound Computed Tomography System (IUCTS) incorporating application of Fuzzy decision making to a transmissive ultrasound tomography

S. Sanei; A. Venkatalachan

1998-01-01

381

ULTRASOUND IMAGE DENOISING VIA MAXIMUM A POSTERIORI ESTIMATION OF WAVELET COEFFICIENTS  

E-print Network

removal by means of digital image processors could improve the diagnostic potential of medical ultrasound the tissue being imaged. Speckle filtering is thus a criti- cal pre-processing step in medical ultrasound1 ULTRASOUND IMAGE DENOISING VIA MAXIMUM A POSTERIORI ESTIMATION OF WAVELET COEFFICIENTS A. Achim1

Tsakalides, Panagiotis

382

Med Phys . Author manuscript MR-guided adaptive focusing of therapeutic ultrasound beams in the  

E-print Network

problem in the field of medical ultrasound: the heterogeneities of biological tissue and skull boneMed Phys . Author manuscript Page /1 12 MR-guided adaptive focusing of therapeutic ultrasound beams High Intensity Focused Ultrasound (HIFU) therapy. Methods Energy-based adaptive focusing techniques

Paris-Sud XI, Université de

383

Comput Biol Med . Author manuscript Fast simulation of ultrasound images from a CT volume  

E-print Network

this model for the standard medical ultrasound image simulation by taking into account the acoustical tissueComput Biol Med . Author manuscript Page /1 8 Fast simulation of ultrasound images from a CT volume-louis.dillenseger@univ-rennes1.fr > Abstract The goal of our work is to propose a fast ultrasound image simulation from CT

Paris-Sud XI, Université de

384

Estimation of speed of sound in dual-layered media using medical ultrasound image deconvolution  

E-print Network

Estimation of speed of sound in dual-layered media using medical ultrasound image deconvolution Ho February 2010 Available online 17 February 2010 Keywords: Medical ultrasound image Dual-layered media Non tissues is usually assumed to be 1540 m/s in medical pulse-echo ultrasound imaging systems. When the true

Kingsbury, Nick

385

Estimation of Speed of Sound in Dual-Layered Media using Medical Ultrasound Image  

E-print Network

Estimation of Speed of Sound in Dual-Layered Media using Medical Ultrasound Image Deconvolution Ho The speed of sound in soft tissues is assumed as 1540 m/s in medical pulse-echo ultrasound imaging systems-speed algorithm, but is comparable to other local speed estimation methods. Keywords: Medical ultrasound image

Kingsbury, Nick

386

Development of Ultrasound Tomography for Breast Imaging: Technical Assessment  

SciTech Connect

Ultrasound imaging is widely used in medicine because of its benign characteristics and real-time capabilities. Physics theory suggests that the application of tomographic techniques may allow ultrasound imaging to reach its full potential as a diagnostic tool allowing it to compete with other tomographic modalities such as X-ray CT and MRI. This paper describes the construction and use of a prototype tomographic scanner and reports on the feasibility of implementing tomographic theory in practice and the potential of US tomography in diagnostic imaging. Data were collected with the prototype by scanning two types of phantoms and a cadaveric breast. A specialized suite of algorithms was developed and utilized to construct images of reflectivity and sound speed from the phantom data. The basic results can be summarized as follows: (1) A fast, clinically relevant US tomography scanner can be built using existing technology. (2) The spatial resolution, deduced from images of reflectivity, is 0.4 mm. The demonstrated 10 cm depth-of-field is superior to that of conventional ultrasound and the image contrast is improved through the reduction of speckle noise and overall lowering of the noise floor. (3) Images of acoustic properties such as sound speed suggest that it is possible to measure variations in the sound speed of 5 m/s. An apparent correlation with X-ray attenuation suggests that the sound speed can be used to discriminate between various types of soft tissue. (4) Ultrasound tomography has the potential to improve diagnostic imaging in relation to breast cancer detection.

Duric, N; Littrup, P; Babkin, A; Chambers, D; Azevedo, S; Arkady, K; Pevzner, R; Tokarev, M; Holsapple, E

2004-09-30

387

Ultrasound triggered, image guided, local drug delivery.  

PubMed

Ultrasound allows the deposition of thermal and mechanical energies deep inside the human body in a non-invasive way. Ultrasound can be focused within a region with a diameter of about 1mm. The bio-effects of ultrasound can lead to local tissue heating, cavitation, and radiation force, which can be used for 1) local drug release from nanocarriers circulating in the blood, 2) increased extravasation of drugs and/or carriers, and 3) enhanced diffusivity of drugs. When using nanocarriers sensitive to mechanical forces (the oscillating ultrasound pressure waves) and/or sensitive to temperature, the content of the nanocarriers can be released locally. Thermo-sensitive liposomes have been suggested for local drug release in combination with local hyperthermia more than 25 years ago. Microbubbles may be designed specifically to enhance cavitation effects. Real-time imaging methods, such as magnetic resonance, optical and ultrasound imaging have led to novel insights and methods for ultrasound triggered drug delivery. Image guidance of ultrasound can be used for: 1) target identification and characterization; 2) spatio-temporal guidance of actions to release or activate the drugs and/or permeabilize membranes; 3) evaluation of bio-distribution, pharmacokinetics and pharmacodynamics; and 4) physiological read-outs to evaluate the therapeutic efficacy. PMID:20709123

Deckers, Roel; Moonen, Chrit T W

2010-11-20

388

Ultrasound Annual, 1983  

SciTech Connect

The 1983 edition of Ultrasound Annual features a state-of-the-art assessment of real-time ultrasound technology and a look at improvements in real-time equipment. Chapters discuss important new obstetric applications of ultrasound in measuring fetal umbilical vein blood flow and monitoring ovarian follicular development in vivo and in vitro fertilization. Other topics covered include transrectal prostate ultrasound using a linear array system; ultrasound of the common bile duct; ultrasound in tropical diseases; prenatal diagnosis of craniospinal anomalies; scrotal ultrasonography; opthalmic ultrasonography; and sonography of the upper abdominal venous system.

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

1983-01-01

389

Automated whole breast ultrasound.  

PubMed

Bilateral whole breast (screening) ultrasound has been well established in multiple single- and multi-institution published studies as a valuable adjunct to mammography screening for early detection of breast cancer. However, implementation of screening breast ultrasound programs has been limited and has met with resistance because of the number of potential false positives generated by ultrasound screening, and the lack of available personnel to perform the examination. Automated breast ultrasound, which has recently been approved by the US Food and Drug Administration for use in whole-breast ultrasound screening, is a potential option for providing breast ultrasound screening on a widespread basis. PMID:24792655

Kaplan, Stuart S

2014-05-01

390

Contrast enhancement and elastography in endoscopic ultrasound: an overview of clinical applications in pancreatic diseases.  

PubMed

Endoscopic ultrasound is a very accurate imaging technique with a relevant clinical impact in the diagnosis and staging of various conditions such as pancreaticobiliary lesions, esophageal cancer, lung cancer, submucosal lesions and lymph nodes. Despite its increasing importance in everyday clinical routine, endoscopic ultrasound outcomes are still highly operator-dependent and tissue confirmation with fine needle aspiration is very often required for definitive differential diagnosis of tumors. Several techniques of image enhancement have been developed in recent years in the attempt to make the technique less operator-dependent. Among them the most important appear to be contrast harmonic-endoscopic ultrasound and endoscopic ultrasound-elastography. Contrast harmonic-endoscopic ultrasound is performed with a dedicated harmonic which displays the fine vascular network of both normal and pathological tissues after injection of an ultrasound contrast agent. Endoscopic ultrasound-elastography displays with different colors the differences in hardness between tissues, thus estimating elasticity in soft normal tissues which appear red and hard neoplastic tissues which appear blue. While contrast harmonic-endoscopic ultrasound has been introduced into clinical practice, endoscopic ultrasound-elastography mainly represents an investigational tool. The purpose of this paper was to review the mechanism of action and the clinical outcomes of contrast harmonic-endoscopic ultrasound and endoscopic ultrasound-elastography in pancreatic diseases. Both techniques show promising applications in the study of pancreatic tumors including differential diagnosis and providing guidance to fine needle aspiration. PMID:25028864

Serrani, M; Caletti, G; Fusaroli, P

2014-10-01

391

Quasi-Static Ultrasound Elastography  

PubMed Central

Elastography is a new imaging modality where elastic tissue parameters related to the structural organization of normal and pathological tissues are imaged. Basic principles underlying the quasi-static elastography concept and principles are addressed. The rationale for elastographic imaging is reinforced using data on elastic properties of normal and abnormal soft tissues. The several orders of magnitude difference between the elastic modulus of normal and abnormal tissues which is the primary contrast mechanism in elastographic imaging underlines the probability of success with this imaging modality. Recent advances enabling the clinical practice of elastographic imaging in real-time on clinical ultrasound systems is also discussed. In quasi-static elastography, radiofrequency echo signals acquired before and after a small (about 1%) of applied deformation are correlated to estimate tissue displacements. Local tissue displacement vector estimates between small segments of the pre- and post-deformation signals are estimated and the corresponding strain distribution imaged. Elastographic imaging techniques are based on the hypothesis that soft tissues deform more than stiffer tissue, and these differences can be quantified in images of the tissue strain tensor or the Young’s modulus. Clinical applications of quasi-static elastography have mushroomed over the last decade, with the most commonly imaged areas being the breast, prostate, thyroid, cardiac, treatment monitoring of ablation procedures and vascular imaging applications. PMID:20798841

Varghese, Tomy

2010-01-01

392

Fat storage in pancreas and in insulin-sensitive tissues in pathogenesis of type 2 diabetes  

Microsoft Academic Search

Obesity is associated with increased storage of lipids in nonadipose tissues like skeletal muscle, liver, and pancreatic ? cells. These lipids constitute a continuous source of long-chain fatty acyl CoA (LC-CoA) and derived metabolites like diacylglycerol and ceramide, acting as signalling molecules on protein kinases activities (in particular, the family of PKCs), ion channel, gene expression, and protein acylation. In

F Assimacopoulos-Jeannet

2004-01-01

393

Effects of Tissue-type and Development on Dark Respiration in Two Herbaceous Perennials  

Microsoft Academic Search

Perennial plants go through a number of developmental stages during the growing season. Changes in metabolism during these phases have been documented in laboratory-grown plants but never in native plants growing in natural habitats. The purpose of this study was to describe the seasonal pattern of dark respiration in the above-ground tissues of two herbaceous perennials, Bistorta bistortoides(Pursh) Small and

Cheryl L. McCutchan; Russell K. Monson

2001-01-01

394

Herpes Simplex Virus Type 1 Infection Facilitates Invasion of Staphylococcus aureus into the Nasal Mucosa and Nasal Polyp Tissue  

PubMed Central

Background Staphylococcus aureus (S. aureus) plays an important role in the pathogenesis of severe chronic airway disease, such as nasal polyps. However the mechanisms underlying the initiation of damage and/or invasion of the nasal mucosa by S. aureus are not clearly understood. The aim of this study was to investigate the interaction between S. aureus and herpes simplex virus type 1 (HSV1) in the invasion of the nasal mucosa and nasal polyp tissue. Methodology/Principal Findings Inferior turbinate and nasal polyp samples were cultured and infected with either HSV1 alone, S. aureus alone or a combination of both. Both in turbinate mucosa and nasal polyp tissue, HSV1, with or without S. aureus incubation, led to focal infection of outer epithelial cells within 48 h, and loss or damage of the epithelium and invasion of HSV1 into the lamina propria within 72 h. After pre-infection with HSV1 for 24 h or 48 h, S. aureus was able to pass the basement membrane and invade the mucosa. Epithelial damage scores were significantly higher for HSV1 and S. aureus co-infected explants compared with control explants or S. aureus only-infected explants, and significantly correlated with HSV1-invasion scores. The epithelial damage scores of nasal polyp tissues were significantly higher than those of inferior turbinate tissues upon HSV1 infection. Consequently, invasion scores of HSV1 of nasal polyp tissues were significantly higher than those of inferior turbinate mucosa in the HSV1 and co-infection groups, and invasion scores of S. aureus of nasal polyp tissues were significantly higher than those of inferior turbinate tissues in the co-infection group. Conclusions/Significance HSV1 may lead to a significant damage of the nasal epithelium and consequently may facilitate invasion of S. aureus into the nasal mucosa. Nasal polyp tissue is more susceptible to the invasion of HSV1 and epithelial damage by HSV1 compared with inferior turbinate mucosa. PMID:22768151

Holtappels, Gabriele; Vaneechoutte, Mario; Krysko, Olga; Zhang, Luo; Han, Demin; Nauwynck, Hans J.; Bachert, Claus

2012-01-01

395

Tissue specific regulation of peripheral-type benzodiazepine receptor density after chemical sympathectomy  

SciTech Connect

The characteristics of (/sup 3/H)Ro 5-4864 binding to peripheral benzodiazepine receptors (PBR) in the central nervous system and peripheral tissues were examined after chemical sympathectomy with 6-hydroxydopamine (6-OHDA). One week after the intracisternal administration of 6-OHDA, the number of (/sup 3/H)Ro 5-4864 binding sites (Bmax) in the hypothalamus and striatum increased 41 and 50% respectively, concurrent with significant reductions in catecholamine content. An increase (34%) in the Bmax of (/sup 3/H)Ro 5-4864 to cardiac ventricle was observed one week after parenteral 6-OHDA administration. In contrast, the B/sub max/ of (/sup 3/H)Ro 5-4684 to pineal gland decreased 48% after 6-OHDA induced reduction in norepinephrine content. The Bmax values for (/sup 3/H)Ro 5-4864 binding to other tissues (including lung, kidney, spleen, cerebral cortex, cerebellum, hippocampus and olfactory bulbs) were unaffected by 6-OHDA administration. The density of pineal, but not cardiac PBR was also reduced after reserpine treatment, an effect reversed by isoproterenol administration. These findings demonstrate that alterations in sympathetic input may regulate the density of PBR in both the central nervous system and periphery in a tissue specific fashion. 33 references, 4 tables.

Basile, A.S.; Skolnick, P.

1988-01-01

396

Prostate Ultrasound  

MedlinePLUS

... sound waves into the body. As the sound waves bounce off internal organs, fluids and tissues, the sensitive microphone in the transducer records tiny changes in the sound's pitch and direction. These signature waves are instantly measured and displayed by a computer, ...

397

Hip Ultrasound  

MedlinePLUS

... sound waves into the body. As the sound waves bounce off internal organs, fluids and tissues, the sensitive microphone in the transducer records tiny changes in the sound's pitch and direction. These signature waves are instantly measured and displayed by a computer, ...

398

Musculoskeletal Ultrasound  

MedlinePLUS

... sound waves into the body. As the sound waves bounce off internal organs, fluids and tissues, the sensitive microphone in the transducer records tiny changes in the sound's pitch and direction. These signature waves are instantly measured and displayed by a computer, ...

399

Cavitation methods in therapeutic ultrasound : techniques, mechanisms, and system design  

E-print Network

Focused ultrasound is currently being developed as a non-invasive thermal ablation technique for benign and cancerous tumors in several organ systems. Although these therapies are designed to ablate tissue purely by thermal ...

Sokka, Shunmugavelu D. (Shunmugavelu Doraivelu), 1975-

2004-01-01

400

Direct Reconstruction Methods in Ultrasound Habib Ammari1  

E-print Network

Ultrasound imaging is a noninvasive, easily portable, and relatively inexpen- sive diagnostic modality which of the technique include the relatively poor soft-tissue contrast and the fact that gas and bone impede the passage

Garnier, Josselin

401

The impact of glottal area discontinuities on block-type vocal fold models with asymmetric tissue properties.  

PubMed

Block-type lumped-element models of the vocal folds are widely used for speech investigations due in part to the rich dynamics exhibited over a range of input parameters, particularly for asymmetric tissue properties. While self-consistent in derivation and application, block-type models of the vocal fold masses are inherently susceptible to non-physical aerodynamic loading conditions when vocal fold motion is highly asymmetric. A standard block-type model is compared against two modified models that disallow the non-physiological loading condition. These minor modifications toward a more physiologically relevant aerodynamic model alter the specific vibration regimes and prevalence of chaos, though bifurcations still exist. PMID:23464131

Sommer, David E; Erath, Byron D; Zañartu, Matías; Peterson, Sean D

2013-03-01