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Ultrasonic Imaging

Anuj Chaudhry, Namhee Kim, Ginu Unnikrishnan, Sanjay Nair, J N Reddy, Raffaella Righetti
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 most diagnostic imaging modalities yet...
September 29, 2016: Ultrasonic Imaging
Sandeep K Kasoji, Emily H Chang, Lee B Mullin, Wui K Chong, W Kimryn Rathmell, Paul A Dayton
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 of perfusion patterns, and we hypothesize that this technique might help differentiate disease subtypes...
September 22, 2016: Ultrasonic Imaging
David Rosen, Yu Wang, Jingfeng Jiang
Viscoelasticity Imaging (VEI) has been proposed to measure relaxation time constants for characterization of in vivo breast lesions. In this technique, an external compression force on the tissue being imaged is maintained for a fixed period of time to induce strain creep. A sequence of ultrasound echo signals is then utilized to generate time-resolved strain measurements. Relaxation time constants can be obtained by fitting local time-resolved strain measurements to a viscoelastic tissue model (e.g., a modified Kevin-Voigt model)...
August 2, 2016: Ultrasonic Imaging
Rebecca E Geist, Chase H DuBois, Timothy C Nichols, Melissa C Caughey, Elizabeth P Merricks, Robin Raymer, Caterina M Gallippi
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 approach enables controlled comparisons of ASSH-derived bleeding rate (BR) and time to hemostasis (TTH) metrics...
September 2016: Ultrasonic Imaging
Teng Ma, Bill Zhou, Tzung K Hsiai, K Kirk Shung
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 imaging modalities used intravascular ultrasound (IVUS) as the technical foundation and integrated emerging intravascular imaging techniques to enhance the characterization of vulnerable plaques...
September 2016: Ultrasonic Imaging
Khaldoon N Altahhan, Yue Wang, Nahil Sobh, Michael F Insana
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...
September 2016: Ultrasonic Imaging
Anne Krejbjerg, Inge Bülow Pedersen, Peter Laurberg
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...
September 2016: Ultrasonic Imaging
Brent K Hoffmeister, Morgan R Smathers, Catherine J Miller, Joseph A McPherson, Cameron R Thurston, P Luke Spinolo, Sang-Rok Lee
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 domain to determine the normalized mean backscatter-difference (nMBD) and in the time domain to determine the normalized backscatter amplitude ratio (nBAR)...
July 2016: Ultrasonic Imaging
Babak Mohammadzadeh Asl
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...
July 2016: Ultrasonic Imaging
Tiexiang Wen, Jia Gu, Ling Li, Wenjian Qin, Lei Wang, Yaoqin Xie
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...
July 2016: Ultrasonic Imaging
Zhong Ji, Wenzheng Ding, Fanghao Ye, Cunguang Lou
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 a multiple data acquisition system, is described, and the capacity of the system is explored experimentally...
July 2016: Ultrasonic Imaging
Deepti Mittal
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 characteristic curves...
June 22, 2016: Ultrasonic Imaging
Mehri Owjimehr, Habibollah Danyali, Mohammad Sadegh Helfroush, Alireza Shakibafard
Fatty liver disease is progressive and may not cause any symptoms at early stages. This disease is potentially fatal and can cause liver cancer in severe stages. Therefore, diagnosing and staging fatty liver disease in early stages is necessary. In this paper, a novel method is presented to classify normal and fatty liver, as well as discriminate three stages of fatty liver in ultrasound images. This study is performed with 129 subjects including 28 normal, 47 steatosis, 42 fibrosis, and 12 cirrhosis images...
June 8, 2016: Ultrasonic Imaging
Olcay Ozveren, Cemil Izgi, Elif Eroglu, Mustafa Aytek Simsek, Ayca Turer, Zekeriya Kucukdurmaz, Veysel Cinar, Muzaffer Degertekin
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 Doppler echocardiography...
May 2016: Ultrasonic Imaging
Gerard Pons, Joan Martí, Robert Martí, Sergi Ganau, J Alison Noble
Breast ultrasound (BUS) imaging has become a crucial modality, especially for providing a complementary view when other modalities (i.e., mammography) are not conclusive in the task of assessing lesions. The specificity in cancer detection using BUS imaging is low. These false-positive findings often lead to an increase of unnecessary biopsies. In addition, increasing sensitivity is also challenging given that the presence of artifacts in the B-mode ultrasound (US) images can interfere with lesion detection...
May 2016: Ultrasonic Imaging
X Wang, C C Mitchell, T Varghese, D C Jackson, B G Rocque, B P Hermann, R J Dempsey
Plaque instability may lead to chronic embolization, which in turn may contribute to progressive cognitive decline. Accumulated strain tensor indices over a cardiac cycle within a pulsating carotid plaque may be viable biomarkers for the diagnosis of plaque instability. Using plaque-only carotid artery segmentations, we recently demonstrated that impaired cognitive function correlated significantly with maximum axial and lateral strain indices within a localized region of interest in plaque. Inclusion of the adventitial layer focuses our strain or instability measures on the vessel wall-plaque interface hypothesized to be a region with increased shearing forces and measureable instability...
May 2016: Ultrasonic Imaging
Elahe Moghimirad, Ali Mahloojifar, Babak Mohammadzadeh Asl
A new frequency-domain implementation of a synthetic aperture focusing technique is presented in the paper. The concept is based on synthetic aperture radar (SAR) and sonar that is a developed version of the convolution model in the frequency domain. Compared with conventional line-by-line imaging, synthetic aperture imaging has a better resolution and contrast at the cost of more computational load. To overcome this problem, point-by-point reconstruction methods have been replaced by block-processing algorithms in radar and sonar; however, these techniques are relatively unknown in medical imaging...
May 2016: Ultrasonic Imaging
Puja Bharti, Deepti Mittal, Rupa Ananthasivan
Diffuse liver diseases, such as hepatitis, fatty liver, and cirrhosis, are becoming a leading cause of fatality and disability all over the world. Early detection and diagnosis of these diseases is extremely important to save lives and improve effectiveness of treatment. Ultrasound imaging, a noninvasive diagnostic technique, is the most commonly used modality for examining liver abnormalities. However, the accuracy of ultrasound-based diagnosis depends highly on expertise of radiologists. Computer-aided diagnosis systems based on ultrasound imaging assist in fast diagnosis, provide a reliable "second opinion" for experts, and act as an effective tool to measure response of treatment on patients undergoing clinical trials...
April 19, 2016: Ultrasonic Imaging
Junhua Zhang, Yuanyuan Wang, Bo Yu, Xinling Shi, Yufeng Zhang
We initiated an observer study to evaluate a computerized system developed in our previous study for automatic extraction of 10 features and estimation of the malignancy probability of cervical nodes in sonograms. In the present study, five expert radiologists and five resident radiologists interpreted the sonograms of 178 nodes. The malignancy rating and patient management recommendation (biopsy or follow-up) were made without and then with the computer aid. Under these two reading conditions, the performances of radiologists and agreement among a group of radiologists were evaluated by using the receiver operating characteristic (ROC) analysis and the κ statistic, respectively...
March 2016: Ultrasonic Imaging
Naglaa Mostafa Elsayed, Yasser Atta Elkhatib
Thyroid nodules are a common medical and surgical concern. Thyroid ultrasound (US) is the primary imaging modality used for initial evaluation and assortment of nodules for fine needle aspiration (FNA) cytology/biopsy. Ultrasound elastography (USE) is believed to improve the diagnostic accuracy of US in distinguishing benign from malignant nodules. The aim of the work described here is to evaluate the diagnostic criteria and accuracy of US and USE in the diagnosis of malignant thyroid nodules. A prospective study of 88 patients who have thyroid nodules was performed...
March 2016: Ultrasonic Imaging
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