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Speckle Tracking in Transcranial Ultrasound Allows Noninvasive Analysis of Pulsation Patterns of the Third Ventricle.
Authors: Würzer B, Laza C, Pons-Kühnemann J, Kaps M, Junge B, Roessler FC Abstract Cerebrospinal fluid (CSF) flow is sensitive to many cerebral disorders. We aimed to develop a noninvasive bedside method to detect physiological and pathological CSF phenomena by measuring pulsation patterns of the third ventricle. By transcranial B-mode ultrasound, electrocardiography (ECG)-gated video loops of the third ventricle were acquired. "Speckle tracking" software was used to quantify the relative change of its width. We conducted measurements of nine cardiac cycles in 11 healthy subjects in sitting and ...
Source: Ultrasonic Imaging - December 8, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

A Quantitative Method for the Evaluation of Spatial Resolution in Quality Control of B-mode Ultrasound Images.
Authors: Strocchi S, Larghi F, Novario R Abstract The work describes a method to quantitatively evaluate spatial resolution in B-mode quality control images as radial modulation transfer function (MTF). The method is easy to use in in-field quality assurance programs in clinical institutions, as it is fast and can be performed with the help of phantoms that are already used for routine quality control. It uses a round insert with different echogenic characteristics compared with the phantom background. The method was automated with a MATLAB® routine, which can be run in full automatic mode or with a grade of in...
Source: Ultrasonic Imaging - November 29, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

Lesion Segmentation in Automated 3D Breast Ultrasound: Volumetric Analysis.
Authors: Agarwal R, Diaz O, Lladó X, Gubern-Mérida A, Vilanova JC, Martí R Abstract Mammography is the gold standard screening technique in breast cancer, but it has some limitations for women with dense breasts. In such cases, sonography is usually recommended as an additional imaging technique. A traditional sonogram produces a two-dimensional (2D) visualization of the breast and is highly operator dependent. Automated breast ultrasound (ABUS) has also been proposed to produce a full 3D scan of the breast automatically with reduced operator dependency, facilitating double reading and comparis...
Source: Ultrasonic Imaging - November 29, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

Analysis of Two Quantitative Ultrasound Approaches.
In this study, the relation between the LF and QUS-derived parameters is studied theoretically and experimentally on ex vivo mouse livers. As expected from the theory, LF slope is correlated to ESD ([Formula: see text]), and from experimental data, LF midband is correlated to EAC ([Formula: see text]). However, LF intercept is not correlated to ESD ([Formula: see text]) nor EAC ([Formula: see text]). The unexpected correlation observed between LF slope and EAC ([Formula: see text]) results likely from the high correlation between ESD and EAC due to the inversion process. For a liver fat percentage estimation, an important ...
Source: Ultrasonic Imaging - September 27, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

3D Tendon Strain Estimation Using High-frequency Volumetric Ultrasound Images: A Feasibility Study.
Authors: Carvalho C, Slagmolen P, Bogaerts S, Scheys L, D'hooge J, Peers K, Maes F, Suetens P Abstract Estimation of strain in tendons for tendinopathy assessment is a hot topic within the sports medicine community. It is believed that, if accurately estimated, existing treatment and rehabilitation protocols can be improved and presymptomatic abnormalities can be detected earlier. State-of-the-art studies present inaccurate and highly variable strain estimates, leaving this problem without solution. Out-of-plane motion, present when acquiring two-dimensional (2D) ultrasound (US) images, is a known problem and may b...
Source: Ultrasonic Imaging - August 24, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

A Review of Ultrasound Tissue Characterization with Mean Scatterer Spacing.
Authors: Zhou Z, Wu W, Wu S, Jia K, Tsui PH Abstract Tissues exhibiting quasi-periodic structures can be modeled as a collection of diffuse scatterers and coherent scatterers. The mean scatterer spacing (MSS) of coherent and quasi-periodic components is directly related to tissue microstructure and has become an important quantitative ultrasound (QUS) parameter in the characterization of quasi-periodic tissues. In this paper, a review of the literature on the development of MSS as a QUS parameter was conducted. First, a unified theoretical background of MSS estimates was provided. Then, the application of MSS estim...
Source: Ultrasonic Imaging - August 13, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

Influence of Tissue Microstructure on Shear Wave Speed Measurements in Plane Shear Wave Elastography: A Computational Study in Lossless Fibrotic Liver Media.
Authors: Wang Y, Jiang J Abstract Shear wave elastography (SWE) has been used to measure viscoelastic properties for characterization of fibrotic livers. In this technique, external mechanical vibrations or acoustic radiation forces are first transmitted to the tissue being imaged to induce shear waves. Ultrasonically measured displacement/velocity is then utilized to obtain elastographic measurements related to shear wave propagation. Using an open-source wave simulator, k-Wave, we conducted a case study of the relationship between plane shear wave measurements and the microstructure of fibrotic liver tissues. Par...
Source: Ultrasonic Imaging - July 21, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

Effects of Phase Aberration and Phase Aberration Correction on the Minimum Variance Beamformer.
In this study, an analysis of the effects of aberration on conventional MV and eigenspace MV (ESMV) beamformers is carried out. In addition, the impact of three PAC algorithms on the performance of MV beamforming is analyzed. The different beamformers were tested on simulated data and on experimental data corrupted with electronic and tissue-based aberration. It is shown that all gains in performance of the MV beamformer with respect to delay-and-sum (DAS) are lost at high aberration strengths. For instance, with an electronic aberration of 60 ns, the lateral resolution of DAS degrades by 17% while MV degrades by 73% with ...
Source: Ultrasonic Imaging - July 15, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

A Method for Gray-Scale Imaging of Blood Flow Using High-Frequency Ultrasound.
This study provides a reliable method for further applications related to diagnoses of superficial organs. PMID: 28703685 [PubMed - as supplied by publisher] (Source: Ultrasonic Imaging)
Source: Ultrasonic Imaging - July 15, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

Low-cost Volumetric Ultrasound by Augmentation of 2D Systems: Design and Prototype.
Authors: Herickhoff CD, Morgan MR, Broder JS, Dahl JJ Abstract Conventional two-dimensional (2D) ultrasound imaging is a powerful diagnostic tool in the hands of an experienced user, yet 2D ultrasound remains clinically underutilized and inherently incomplete, with output being very operator dependent. Volumetric ultrasound systems can more fully capture a three-dimensional (3D) region of interest, but current 3D systems require specialized transducers, are prohibitively expensive for many clinical departments, and do not register image orientation with respect to the patient; these systems are designed to provide ...
Source: Ultrasonic Imaging - July 12, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

Material Properties of Human Ocular Tissue at 7- µm Resolution.
Material Properties of Human Ocular Tissue at 7-µm Resolution. Ultrason Imaging. 2017 Jul 01;:161734617713498 Authors: Rohrbach D, Ito K, Lloyd HO, Silverman RH, Yoshida K, Yamaguchi T, Mamou J Abstract Quantitative assessment of the material properties of ocular tissues can provide valuable information for investigating several ophthalmic diseases. Quantitative acoustic microscopy (QAM) offers a means of obtaining such information, but few QAM investigations have been conducted on human ocular tissue. We imaged the optic nerve (ON) and iridocorneal angle in 12-µm deparaffinized sections of...
Source: Ultrasonic Imaging - July 7, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

Compressed Sensing for Elastography in Portable Ultrasound.
Authors: Shin B, Jeon S, Ryu J, Kwon HJ Abstract Portable ultrasound is recently emerging as a new medical imaging modality featuring high portability, easy connectivity, and real-time on-site diagnostic ability. However, it does not yet provide ultrasound elastography function that enables the diagnosis of malignant lesions using elastic properties. This is mainly due to the limitations of hardware performance and wireless data transfer speed for processing the large amount of data for elastography. Therefore, data transfer reduction is one of the feasible solutions to overcome these limitations. Recently, compres...
Source: Ultrasonic Imaging - July 5, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

GPU-accelerated Kernel Regression Reconstruction for Freehand 3D Ultrasound Imaging.
Authors: Wen T, Li L, Zhu Q, Qin W, Gu J, Yang F, Xie Y Abstract Volume reconstruction method plays an important role in improving reconstructed volumetric image quality for freehand three-dimensional (3D) ultrasound imaging. By utilizing the capability of programmable graphics processing unit (GPU), we can achieve a real-time incremental volume reconstruction at a speed of 25-50 frames per second (fps). After incremental reconstruction and visualization, hole-filling is performed on GPU to fill remaining empty voxels. However, traditional pixel nearest neighbor-based hole-filling fails to reconstruct volume with h...
Source: Ultrasonic Imaging - June 21, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

Dynamic Transmit-Receive Beamforming by Spatial Matched Filtering for Ultrasound Imaging with Plane Wave Transmission.
Authors: Chen Y, Lou Y, Yen J Abstract During conventional ultrasound imaging, the need for multiple transmissions for one image and the time of flight for a desired imaging depth limit the frame rate of the system. Using a single plane wave pulse during each transmission followed by parallel receive processing allows for high frame rate imaging. However, image quality is degraded because of the lack of transmit focusing. Beamforming by spatial matched filtering (SMF) is a promising method which focuses ultrasonic energy using spatial filters constructed from the transmit-receive impulse response of the system. Stu...
Source: Ultrasonic Imaging - June 21, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

Three-dimensional Ultrasound Elasticity Imaging on an Automated Breast Volume Scanning System.
Authors: Wang Y, Nasief HG, Kohn S, Milkowski A, Clary T, Barnes S, Barbone PE, Hall TJ Abstract Ultrasound elasticity imaging has demonstrated utility in breast imaging, but it is typically performed with handheld transducers and two-dimensional imaging. Two-dimensional (2D) elastography images tissue stiffness of only a plane and hence suffers from errors due to out-of-plane motion, whereas three-dimensional (3D) data acquisition and motion tracking can be used to track out-of-plane motion that is lost in 2D elastography systems. A commercially available automated breast volume scanning system that acquires 3D ul...
Source: Ultrasonic Imaging - June 8, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

Quantitative Muscle Ultrasonography Using Textural Analysis in Amyotrophic Lateral Sclerosis.
Authors: Martínez-Payá JJ, Ríos-Díaz J, Del Baño-Aledo ME, Tembl-Ferrairó JI, Vazquez-Costa JF, Medina-Mirapeix F Abstract The purpose of this study was to analyze differences in gray-level co-occurrence matrix (GLCM) parameters, as assessed by muscle ultrasound (MUS), between amyotrophic lateral sclerosis (ALS) patients and healthy controls, and to compare the diagnostic accuracy of these GLCM parameters with first-order MUS parameters (echointensity [EI], echovariation [EV], and muscle thickness [MTh]) in different muscle groups. Twenty-six patients with ALS and 26 health...
Source: Ultrasonic Imaging - May 30, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

Three-dimensional Simulation of Quantitative Ultrasound in Cancellous Bone Using the Echographic Response of a Metallic Pin.
Authors: Nagatani Y, Guipieri S, Nguyen VH, Chappard C, Geiger D, Naili S, Haїat G Abstract Degenerative discopathy is a common pathology that may require spine surgery. A metallic cylindrical pin is inserted into the vertebral body to maintain soft tissues and may be used as a reflector of ultrasonic wave to estimate bone density. The first aim of this paper is to validate a three-dimensional (3-D) model to simulate the ultrasonic propagation in a trabecular bone sample in which a metallic pin has been inserted. We also aim at determining the effect of changes of bone volume fraction (BV/TV) and of positioning er...
Source: Ultrasonic Imaging - May 13, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

Frequency Representation: Visualization and Clustering of Acoustic Data Using Self-Organizing Maps.
In this study, frequency representation (FR) based on phase information in multispectral acoustic imaging (MSAI) is proposed to overcome the limit of intensity or amplitude information in image display. Experiments are performed on 3D acoustic data collected from a rigid surface engraved with five different letters. The results show that the proposed FR technique can not only identify the depth of the five letters by the colors representing frequency characteristics but also demonstrate the 3D image of the five letters, providing more detailed characteristics that are unavailable by conventional acoustic imaging. PMID:...
Source: Ultrasonic Imaging - May 6, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

Diagnostic Value of Acoustic Radiation Force Impulse Quantification in the Differentiation of Benign and Malignant Thyroid Nodules.
The objective of this study was to evaluate the role of ultrasound elastography using acoustic radiation force impulse (ARFI) quantification in characterizing and differentiating malignant versus benign thyroid nodules. A total of 40 thyroid nodules were evaluated with conventional sonography and ultrasound elastography using ARFI quantification. The final diagnosis was obtained from histologic findings. A total of 14 malignant and 26 benign nodules were diagnosed on the basis of histologic examination. Majority of the malignant thyroid nodules demonstrated presence of intranodular vascular flow, hypoechoic echotexture, ab...
Source: Ultrasonic Imaging - May 6, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

Lower Bound on Estimation Variance of the Ultrasonic Attenuation Coefficient Using the Spectral-Difference Reference-phantom Method.
Authors: Samimi K, Varghese T Abstract Ultrasonic attenuation is one of the primary parameters of interest in Quantitative Ultrasound (QUS). Non-invasive monitoring of tissue attenuation can provide valuable diagnostic and prognostic information to the physician. The Reference Phantom Method (RPM) was introduced as a way of mitigating some of the system-related effects and biases to facilitate clinical QUS applications. In this paper, under the assumption of diffuse scattering, a probabilistic model of the backscattered signal spectrum is used to derive a theoretical lower bound on the estimation variance of the at...
Source: Ultrasonic Imaging - April 22, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

High-Frequency Ultrasonic Imaging with Lead-free (Na,K)(Nb,Ta)O3 Single Crystal.
Authors: Chen Z, Zheng L, Cao W, Chen X, Chen R, Li R, Shung K, Zhou Q Abstract Lead-free (Na,K)(Nb,Ta)O3 (KNNT) piezoelectric single crystal has been successfully grown using the top-seeded solution growth technique. The electromechanical coupling factors are very high ( k33 = 0.827, kt = 0.646), and the dielectric loss tangent is as low as 0.004. Acoustic impedance was calculated to be 26.5 MRayl. From the single crystal, a single element transducer was fabricated. The transducer achieved a 57.6% -6 dB bandwidth and 32.3 µm axial resolution at the center frequency of 45.4 MHz, which can identify the cornea ...
Source: Ultrasonic Imaging - April 13, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

A Coaxial Dual-element Focused Ultrasound Probe for Guidance of Epidural Catheterization.
Authors: Dong GC, Chiu LC, Ting CK, Hsu JR, Huang CC, Chang Y, Chen GS Abstract Ultrasound guidance for epidural block has improved clinical blind-trial problems but the design of present ultrasonic probes poses operating difficulty of ultrasound-guided catheterization, increasing the failure rate. The purpose of this study was to develop a novel ultrasonic probe to avoid needle contact with vertebral bone during epidural catheterization. The probe has a central circular passage for needle insertion. Two focused annular transducers are deployed around the passage for on-axis guidance. A 17-gauge insulated Tuohy nee...
Source: Ultrasonic Imaging - March 28, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

Rotation Elastogram Estimation Using Synthetic Transmit Aperture Technique.
Authors: B L, Chintada BR, Thittai AK Abstract It is well-documented in literature that benign breast lesions, such as fibroadenomas, are loosely bonded to their surrounding tissue and tend to slip under a small quasi-static compression, whereas malignant lesions being firmly bonded to their surrounding tissue do not slip. Recent developments in quasi-static ultrasound elastography have shown that an image of the axial-shear strain distribution can provide information about the bonding condition at the lesion-surrounding tissue boundary. Further studies analyzing the axial-shear strain elastograms revealed that non...
Source: Ultrasonic Imaging - January 18, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

Short-lag Spatial Coherence Ultrasound Imaging with Adaptive Synthetic Transmit Aperture Focusing.
Authors: Zhao J, Wang Y, Yu J, Guo W, Zhang S, Aliabadi S Abstract The short-lag spatial coherence (SLSC) imaging has been demonstrated to be advantageous over the traditional B-mode ultrasound imaging. With focused scanning beams, the SLSC imaging has an excellent performance in clutter reduction and lesion detection, especially in the low signal-to-noise ratio (SNR) scenarios. The synthetic aperture (SA) imaging is an appropriate mode for the SLSC imaging as the dynamic transmit focusing could keep a good focusing quality at any depth. However, the SLSC image may still suffer a bad resolution performance when a l...
Source: Ultrasonic Imaging - January 12, 2017 Category: Radiology Tags: Ultrason Imaging Source Type: research

A Color Doppler Shear Wave Imaging Phase Reconstruction Method Using Four Color Flow Images.
This study investigates shear wave phase map reconstruction using a limited number of color flow images (CFIs) acquired with a color Doppler ultrasound imaging instrument. We propose an efficient reconstruction method to considerably reduce the number of CFIs required for reconstruction and compare this method with Fourier analysis-based color Doppler shear wave imaging. The proposed method uses a two-step phase reconstruction process, including an initial phase map derived from four CFIs using an advanced iterative algorithm of optical interferometry. The second step reduces phase artifacts in the initial phase map using ...
Source: Ultrasonic Imaging - December 3, 2016 Category: Radiology Tags: Ultrason Imaging Source Type: research

Effect of Interstitial Fluid Pressure on Ultrasound Axial Strain and Axial Shear Strain Elastography.
Authors: Chaudhry A, Kim N, Unnikrishnan G, Nair S, Reddy JN, Righetti R Abstract Ultrasound elastography is an imaging modality that has been used to diagnose tumors of the breast, thyroid, and prostate. Both axial strain elastography and axial shear strain elastography (ASSE) have shown significant potentials to differentiate between benign and malignant tumors. Elevated interstitial fluid pressure (IFP) is a characteristic of many malignant tumors and a major barrier in targeted drug delivery therapies. This parameter, however, has not received significant attention in ultrasound elastography and, in general, in...
Source: Ultrasonic Imaging - October 5, 2016 Category: Radiology Tags: Ultrason Imaging Source Type: research

Staging of Fatty Liver Diseases Based on Hierarchical Classification and Feature Fusion for Back-Scan-Converted Ultrasound Images.
This study is performed with 129 subjects including 28 normal, 47 steatosis, 42 fibrosis, and 12 cirrhosis images. The proposed approach uses back-scan conversion of ultrasound sector images and is based on a hierarchical classification. The proposed algorithm is performed in two parts. The first part selects the optimum regions of interest from the focal zone of the back-scan-converted ultrasound images. In the second part, discrimination between normal and fatty liver is performed and then steatosis, fibrosis, and cirrhosis are classified in a hierarchical basis. The wavelet packet transform and gray-level co-occurrence ...
Source: Ultrasonic Imaging - October 5, 2016 Category: Radiology Tags: Ultrason Imaging Source Type: research

A Pilot Clinical Study in Characterization of Malignant Renal Cell Carcinoma Subtype with Contrast-Enhanced Ultrasound.
Authors: Kasoji SK, Chang EH, Mullin LB, Chong WK, Rathmell WK, Dayton PA Abstract Malignant renal cell carcinoma (RCC) is a diverse set of diseases, which are independently difficult to characterize using conventional MRI and CT protocols due to low temporal resolution to study perfusion characteristics. Because different disease subtypes have different prognoses and involve varying treatment regimens, the ability to determine RCC subtype non-invasively is a clinical need. Contrast-enhanced ultrasound (CEUS) has been assessed as a tool to characterize kidney lesions based on qualitative and quantitative assessment...
Source: Ultrasonic Imaging - September 25, 2016 Category: Radiology Tags: Ultrason Imaging Source Type: research

Virtual Breast Quasi-Static Elastography (VBQE): A Case Study in Contrast Transfer Efficiency of Viscoelastic Imaging.
In this study, our primary objective is to quantitatively evaluate the contrast transfer efficiency (CTE) of VEI, which contains useful information regarding image interpretations. Using an open-source simulator for virtual breast quasi-static elastography (VBQE), we conducted a case study of contrast transfer efficiency of VEI. In multiple three-dimensional (3D) numerical breast phantoms containing various degrees of heterogeneity, finite element (FE) simulations in conjunction with quasi-linear viscoelastic constitutive tissue models were performed to mimic data acquisition of VEI under freehand scanning. Our results sug...
Source: Ultrasonic Imaging - August 6, 2016 Category: Radiology Tags: Ultrason Imaging Source Type: research

Impact of Modified Anisotropic Diffusion-Based Enhancement Method in Computer-Aided Classification of Focal Liver Lesions.
Authors: Mittal D Abstract This work is presented with the objective to assess quantitatively the impact of modified anisotropic diffusion-based enhancement method of Mittal et al. in computer-aided classification of focal liver lesions. This assessment was made before and after enhancement of clinically acquired ultrasound images with the comparison of (a) discrimination capability of radiologically important texture contrast feature using box plot and p-value statistics and (b) test results of designed computer-aided classification schemes to detect/classify focal liver tissues using receiver operating characteri...
Source: Ultrasonic Imaging - June 25, 2016 Category: Radiology Tags: Ultrason Imaging Source Type: research

Computer-Aided Characterization and Diagnosis of Diffuse Liver Diseases Based on Ultrasound Imaging: A Review.
Authors: Bharti P, Mittal D, Ananthasivan R Abstract Diffuse liver diseases, such as hepatitis, fatty liver, and cirrhosis, are becoming a leading cause of fatality and disability all over the world. Early detection and diagnosis of these diseases is extremely important to save lives and improve effectiveness of treatment. Ultrasound imaging, a noninvasive diagnostic technique, is the most commonly used modality for examining liver abnormalities. However, the accuracy of ultrasound-based diagnosis depends highly on expertise of radiologists. Computer-aided diagnosis systems based on ultrasound imaging assist in fas...
Source: Ultrasonic Imaging - April 23, 2016 Category: Radiology Tags: Ultrason Imaging Source Type: research

Improvement of Lesion Detection by Complete Angular Compound Ultrasonic Elastography.
Authors: Liu C, Zhou Y Abstract Quasi -: static ultrasound elastography is an emerging diagnostic imaging modality for determining the stiffness of pathologically changed soft tissues, which do not show significant differences in acoustic impedance for B-mode imaging. Although some methods were applied to improve the signal-to-noise ratio (SNRe) and contrast-to-noise ratio (CNRe) of the constructed elastogram, nonuniform strain distribution at the internal boundary of a hard inclusion, even with the uniform displacement on the surface, is an inherent mechanical effect and results in distortion at the detected lesio...
Source: Ultrasonic Imaging - January 28, 2016 Category: Radiology Tags: Ultrason Imaging Source Type: research

Vector Flow Imaging Compared with Conventional Doppler Ultrasound and Thermodilution for Estimation of Blood Flow in the Ascending Aorta.
Authors: Hansen KL, Møller-Sørensen H, Kjaergaard J, Jensen MB, Lund JT, Pedersen MM, Olesen JB, Jensen JA, Nielsen MB Abstract Transverse oscillation (TO) is a real-time ultrasound vector flow method implemented on a commercial scanner. The TO setup was examined on a flowrig with constant and pulsatile flow. Subsequently, 25 patients undergoing cardiac bypass surgery were scanned intraoperatively with TO on the ascending aorta and compared to transesophageal echocardiography (TEE) and pulmonary artery catheter thermodilution (PACTD). On the flowrig, TO had a precision of 5.5%, 9.4% and 14.7%, a perce...
Source: Ultrasonic Imaging - December 27, 2015 Category: Radiology Tags: Ultrason Imaging Source Type: research

Foreword to the Special Issue of Ultrasonic Imaging on Biomedical Imaging with Combined Light and Sound.
Authors: Wang X, Feleppa E PMID: 26675216 [PubMed - in process] (Source: Ultrasonic Imaging)
Source: Ultrasonic Imaging - December 20, 2015 Category: Radiology Tags: Ultrason Imaging Source Type: research

Chirp-Coded Ultraharmonic Imaging with a Modified Clinical Intravascular Ultrasound System.
In this study, we evaluated the performance of chirp-coded ultraharmonic imaging using a modified IVUS system (iLab™, Boston Scientific/Scimed) equipped with clinically available peripheral and coronary imaging catheters. Flow phantoms perfused with a phospholipid-encapsulated contrast agent were visualized using ultraharmonic imaging at 12 MHz and 30 MHz transmit frequencies. Flow channels with diameters as small as 0.8 mm and 0.5 mm were visualized using the peripheral and coronary imaging catheters. Radio-frequency signals were acquired at standard IVUS rotation speed, which resulted in a frame rate of 30 frames/s...
Source: Ultrasonic Imaging - December 8, 2015 Category: Radiology Tags: Ultrason Imaging Source Type: research

Experimental Validation of ARFI Surveillance of Subcutaneous Hemorrhage (ASSH) Using Calibrated Infusions in a Tissue-Mimicking Model and Dogs.
Authors: Geist RE, DuBois CH, Nichols TC, Caughey MC, Merricks EP, Raymer R, Gallippi CM Abstract Acoustic radiation force impulse (ARFI) Surveillance of Subcutaneous Hemorrhage (ASSH) has been previously demonstrated to differentiate bleeding phenotype and responses to therapy in dogs and humans, but to date, the method has lacked experimental validation. This work explores experimental validation of ASSH in a poroelastic tissue-mimic and in vivo in dogs. The experimental design exploits calibrated flow rates and infusion durations of evaporated milk in tofu or heparinized autologous blood in dogs. The validation ...
Source: Ultrasonic Imaging - December 2, 2015 Category: Radiology Tags: Ultrason Imaging Source Type: research

Segmental Analysis of Cardiac Short-Axis Views Using Lagrangian Radial and Circumferential Strain.
Authors: Ma C, Wang X, Varghese T Abstract Accurate description of myocardial deformation in the left ventricle is a three-dimensional problem, requiring three normal strain components along its natural axis, that is, longitudinal, radial, and circumferential strains. Although longitudinal strains are best estimated from long-axis views, radial and circumferential strains are best depicted in short-axis views. An algorithm that utilizes a polar grid for short-axis views previously developed in our laboratory for a Lagrangian description of tissue deformation is utilized for radial and circumferential displacement a...
Source: Ultrasonic Imaging - November 22, 2015 Category: Radiology Tags: Ultrason Imaging Source Type: research

Segmentation of Breast Lesions in Ultrasound Images through Multiresolution Analysis Using Undecimated Discrete Wavelet Transform.
Authors: Prabusankarlal KM, Thirumoorthy P, Manavalan R Abstract Earliest detection and diagnosis of breast cancer reduces mortality rate of patients by increasing the treatment options. A novel method for the segmentation of breast ultrasound images is proposed in this work. The proposed method utilizes undecimated discrete wavelet transform to perform multiresolution analysis of the input ultrasound image. As the resolution level increases, although the effect of noise reduces, the details of the image also dilute. The appropriate resolution level, which contains essential details of the tumor, is automatically s...
Source: Ultrasonic Imaging - November 22, 2015 Category: Radiology Tags: Ultrason Imaging Source Type: research

Backscatter Difference Measurements of Cancellous Bone Using an Ultrasonic Imaging System.
Authors: Hoffmeister BK, Smathers MR, Miller CJ, McPherson JA, Thurston CR, Spinolo PL, Lee SR Abstract Backscatter difference measurements may be used to detect changes in bone caused by osteoporosis. The backscatter difference technique measures the power difference between two portions of an ultrasonic backscatter signal. The goal of this study is to evaluate the feasibility of using an ultrasonic imaging system to perform backscatter difference measurements of bone. Ultrasonic images and backscatter signals were acquired from 24 specimens of human cancellous bone. The signals were analyzed in the frequency doma...
Source: Ultrasonic Imaging - September 30, 2015 Category: Radiology Tags: Ultrason Imaging Source Type: research

40th International Symposium on Ultrasonic Imaging and Tissue Characterization, Program and Abstracts.
Authors: PMID: 26391527 [PubMed - in process] (Source: Ultrasonic Imaging)
Source: Ultrasonic Imaging - September 26, 2015 Category: Radiology Tags: Ultrason Imaging Source Type: research

A Review of Intravascular Ultrasound-Based Multimodal Intravascular Imaging: The Synergistic Approach to Characterizing Vulnerable Plaques.
Authors: Ma T, Zhou B, Hsiai TK, Shung KK Abstract Catheter-based intravascular imaging modalities are being developed to visualize pathologies in coronary arteries, such as high-risk vulnerable atherosclerotic plaques known as thin-cap fibroatheroma, to guide therapeutic strategy at preventing heart attacks. Mounting evidences have shown three distinctive histopathological features-the presence of a thin fibrous cap, a lipid-rich necrotic core, and numerous infiltrating macrophages-are key markers of increased vulnerability in atherosclerotic plaques. To visualize these changes, the majority of catheter-based imag...
Source: Ultrasonic Imaging - September 26, 2015 Category: Radiology Tags: Ultrason Imaging Source Type: research

Indentation Measurements to Validate Dynamic Elasticity Imaging Methods.
We describe macro-indentation techniques for estimating the elastic modulus of soft hydrogels. Our study describes (a) conditions under which quasi-static indentation can validate dynamic shear-wave imaging estimates and (b) how each of these techniques uniquely biases modulus estimates as they couple to the sample geometry. Harmonic shear waves between 25 and 400 Hz were imaged using ultrasonic Doppler and optical coherence tomography methods to estimate shear dispersion. From the shear-wave speed of sound, average elastic moduli of homogeneous samples were estimated. These results are compared directly with macroscopic i...
Source: Ultrasonic Imaging - September 18, 2015 Category: Radiology Tags: Ultrason Imaging Source Type: research

Can Elastography Predict Growth of Incidental Thyroid Nodules? A Pilot Two-Year Follow-Up Study.
The objective of this study was to examine the ultrasonography (US) and ultrasound elastography (USE) features of thyroid incidentalomas in a population exposed to iodine deficiency and to investigate whether baseline elasticity scores (ES) predicted changes in thyroid nodule US characteristics. We conducted a two-year follow-up pilot study of thyroid incidentalomas by US and USE. One sonographer performed the US and USE examination on the same apparatus at baseline and at follow-up. We evaluated 83 incidental thyroid nodules detected in a population study. The follow-up period saw no change in median thyroid nodule diamet...
Source: Ultrasonic Imaging - September 11, 2015 Category: Radiology Tags: Ultrason Imaging Source Type: research

Combining the APES and Minimum Variance Beamformers for Adaptive Ultrasound Imaging.
Authors: Mohammadzadeh Asl B Abstract In recent years, adaptive minimum variance (MV) beamforming has been successfully applied to medical ultrasound imaging, resulting in simultaneous improvement in imaging resolution and contrast. MV has high resolution and hence can provide accurate estimates of the target locations. However, the MV amplitude estimates are significantly biased downward, especially when occurring the errors in model parameters. The amplitude and phase estimation (APES) beamformer gives much more accurate amplitude estimates at the target locations, but at the cost of lower resolution. To reap the...
Source: Ultrasonic Imaging - September 6, 2015 Category: Radiology Tags: Ultrason Imaging Source Type: research

Nonlocal Total Variation-Based Speckle Filtering for Ultrasound Images.
Authors: Wen T, Gu J, Li L, Qin W, Wang L, Xie Y Abstract Ultrasound is one of the most important medical imaging modalities for its real-time and portable imaging advantages. However, the contrast resolution and important details are degraded by the speckle in ultrasound images. Many speckle filtering methods have been developed, but they are suffered from several limitations, difficult to reach a balance between speckle reduction and edge preservation. In this paper, an adaptation of the nonlocal total variation (NLTV) filter is proposed for speckle reduction in ultrasound images. The speckle is modeled via a sig...
Source: Ultrasonic Imaging - September 3, 2015 Category: Radiology Tags: Ultrason Imaging Source Type: research

Handheld Thermoacoustic Scanning System Based on a Linear Array Transducer.
Authors: Ji Z, Ding W, Ye F, Lou C Abstract To receive the information necessary for imaging, traditional microwave-induced thermoacoustic imaging systems (MITISs) use a type of circular-scanning mode using single or arc detectors. However, the use of MITISs for body scanning is complicated by restrictions in space and imaging time. A linear array detector, the most widely used transducer in medical ultrasound imaging systems for body scanning, is a possible alternative to MITISs for scanning biological tissues, such as from the breast or limbs. In this paper, a handheld MITIS, based on a linear array detector and ...
Source: Ultrasonic Imaging - August 22, 2015 Category: Radiology Tags: Ultrason Imaging Source Type: research

Doppler Tissue Evaluation of Atrial Conduction Properties in Patients With Non-Alcoholic Fatty Liver Disease.
Authors: Ozveren O, Izgi C, Eroglu E, Simsek MA, Turer A, Cinar V, Degertekin M Abstract Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in clinical practice, and there is an increasing trend in its prevalence in the general population. Recent studies have demonstrated increased risk of atrial fibrillation (AF) in NAFLD. However, information on the mechanism of increased risk of AF in NAFLD is lacking. Impaired atrial conduction is an important factor in the pathophysiology of AF. We aimed to investigate atrial conduction properties in patients with NAFLD by tissue Dopple...
Source: Ultrasonic Imaging - July 15, 2015 Category: Radiology Tags: Ultrason Imaging Source Type: research

Experimental Investigation of Inter-Element Isolation in a Medical Array Transducer at Various Manufacturing Stages.
Authors: Marinozzi F, Bini F, Grandoni A Abstract This work presents the experimental investigation of vibration maps of a linear array transducer with 192 piezoelements by means of a laser Doppler vibrometer at various manufacturing finishing steps in air and in water. Over the years, many researchers have investigated cross-coupling in fabricated prototypes but not in arrays at various manufacturing stages. Only the central element of the array was driven at its working frequency of 5 MHz. The experimental results showed that the contributions of cross-coupling depend on the elements of the acoustic stack: Lead Z...
Source: Ultrasonic Imaging - July 15, 2015 Category: Radiology Tags: Ultrason Imaging Source Type: research

Multi-Wavelength Photoacoustic Visualization of High Intensity Focused Ultrasound Lesions.
This study suggests that multi-wavelength PA imaging has potential to obtain accurate characterization of HIFU lesion extent and may be better suited to guide HIFU ablation therapies during clinical treatments than single-wavelength methods. PMID: 26149314 [PubMed - as supplied by publisher] (Source: Ultrasonic Imaging)
Source: Ultrasonic Imaging - July 11, 2015 Category: Radiology Tags: Ultrason Imaging Source Type: research

Three-Dimensional Optoacoustic and Laser-Induced Ultrasound Tomography System for Preclinical Research in Mice: Design and Phantom Validation.
Authors: Ermilov SA, Su R, Conjusteau A, Anis F, Nadvoretskiy V, Anastasio MA, Oraevsky AA Abstract In this work, we introduce a novel three-dimensional imaging system for in vivo high-resolution anatomical and functional whole-body visualization of small animal models developed for preclinical and other type of biomedical research. The system (LOUIS-3DM) combines a multiwavelength optoacoustic tomography (OAT) and laser-induced ultrasound tomography (LUT) to obtain coregistered maps of tissue optical absorption and speed of sound, displayed within the skin outline of the studied animal. The most promising applicat...
Source: Ultrasonic Imaging - June 22, 2015 Category: Radiology Tags: Ultrason Imaging Source Type: research