The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Accurate diagnosis of non-alcoholic steatohepatitis (NASH) is a critical issue in current clinical practice. Non-invasive diagnosis of NASH can be achieved by quantitative ultrasound (QUS), which requires a detailed understanding tissue-specific acoustic microstructure at cellular scale (i.e., 10 μm). Therefore, QUS methods would benefit from the knowledge of the acoustic properties of organelles...
Acoustic Angiography enables high resolution and high SNR imaging of microbubble contrast agents. The technique relies on pulsing and receiving at two widely separated acoustic bandwidths to reject signal from the tissue. To date this technique has been used to evaluate microvasculature within tumors and kidneys, but has not been used to visualize in vivo blood flow within heart, or liver. These targets...
Point shear wave elastography (pSWE) provides noninvasive measures of mechanical stiffness of biological tissue. Over the past decade, research has demonstrated that pSWE is effective at diagnosing a multitude of pathologies such as liver fibrosis and cancer. Life science researchers stand to benefit tremendously from access to pSWE but a number of challenges have limited its use in small animals...
Current liver cancer ablation methods are mainly thermal-based and inherently exhibit inconsistent tissue ablation due to irregular heat dissipation. Histotripsy is a non-thermal ultrasound (US) ablation method that fractionates tissue through the precise control of acoustic cavitation. This paper studies the feasibility and chronic effects of non-invasive histotripsy for liver cancer ablation in...
Vascular remodeling agents that can enhance the effects of chemotherapy have gained significant attention. However, timing and dosing of combinatory treatment regimens requires longitudinal biomarkers to optimize regimens on a patient-by-patient basis. 3D dynamic contrast-enhanced ultrasound (DCE-US) has been proposed as an inexpensive bedside tool to longitudinally guide dosing and scheduling of...
Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease and can often lead to fibrosis, cirrhosis, cancer and complete liver failure. Liver biopsy is the current standard of care to quantify hepatic steatosis but it comes with increased patient risk and only samples a small portion of the liver. Imaging approaches to assess NAFLD include proton density fat fraction...
There are two generally used ultrasonic approaches to extract sets of quantitative parameters: the Lizzi-Feleppa (LF) and quantitative ultrasound (QUS) approaches. The LF approach estimates LF parameters from the linear fit of the backscatter coefficient (BSC), and yields slope, intercept and midband. The QUS approach relies on the attenuation coefficient (AC) and BSC versus frequency, and yields...
Targeting the ultrasound beam and predicting the thermal coagulation in advance are important for high-intensity focused ultrasound (HIFU) treatment. Cavitation bubbles are known to enhance ultrasonic heating, however, temporal and spatial control of their generation is not simple. In our previous study, a method utilizing acoustic radiation force to predict thermal coagulation was suggested. In this...
Diagnosis and assessment of liver fibrosis grade required for management is mainly based on blood tests and invasive hepatic puncture-biopsy. Quantitative UltraSound (QUS) techniques provide insight into tissue microstructure and are based on the frequency-based analysis of the signals from biological tissues. This study aims to explore the diagnostic performance of QUS technique in high frequency...
Shear Wave Elasticity Imaging is used to assess liver fibrosis, as shear wave speed (SWS) correlates with fibrosis stage. We have previously proposed a group SWS-based method to derive the tissue's stiffness (μ) and viscosity (η) using an analytic solution for the shear wave propagation in a Voigt material which accounts for the source excitation geometry [Rouze et al., IEEE IUS 2016]. However, in...
A challenge in the clinical application of shear wave elastography is the level of measurement variance or noise compared to clinically significant changes in shear wave speed. For instance, liver fibrosis staging is challenged by the relatively high variance of shear wave velocity estimates in comparison to the modulus difference between early (F1-F3) fibrosis stages. Recent work has shown that ultrasound...
It is highly desirable to monitor microwave ablation (MWA) treatments noninvasively for substantially improving the clinical implementation of MWA procedures and progress toward full clinical uses worldwide. This in vivo study explored the feasibility of using ultrasonic Nakagami imaging to evaluate the thermal lesions in liver and kidney in a porcine model for the purpose of monitoring MWA.
Ultrasound elastography is an effective imaging modality to delineate thermally ablated regions after ablative liver tumor treatments. The image contrast is based on the difference in the Young's modulus of local tissue. In this work, we compared our previously introduced electrode displacement elastography (EDE) with a commercially available acoustic radiation force impulse imaging (ARFI) technique,...
Probe oscillation shear wave elastography (PROSE) can achieve high frame-rate two-dimensional (2D) shear wave elastography by utilizing a continuously vibrating ultrasound probe to simultaneously generate and detect shear waves (Mellema, IEEE TMI 0278-0062). Strategically detecting when the probe returns to the same physical location allowed the shear waves to be decoupled from probe motion artifacts;...
Non-alcoholic fatty liver disease (NAFLD) is a major health concern due to the increasing obesity epidemic and it has the risk to progress to liver fibrosis, cirrhosis and hepatocellular carcinoma. It is important to assess the severity of hepatic fibrosis for the risk-stratified management of patients with NAFLD. Ultrasound elastography is a new technique for evaluation of liver fibrosis and it has...
Commercially available tissue-mimicking-materials (TMMs) and phantoms are designed to exhibit acoustic properties similar to those measured from soft tissue at ultrasound frequencies up to 15MHz. Many of these phantoms are manufacturing using the IEC agar-TMM. However, there are increasing applications of ultrasound at frequencies above 15MHz for both clinical (skin and vascular) and preclinical (small...
In chronic hepatitis diagnosis, shear wave elastography is utilized for evaluating fibrosis progression. It is expected that the accuracy will be improved by measuring the viscosity in addition to the elasticity. However, the shear wave dispersion in analyzing liver viscosity is affected by both viscosity and fibrous structure. In order to quantitatively evaluate hepatic fibrosis, we evaluated the...
Dynamic contrast enhanced ultrasound (DCE-US) is a low-cost tool proposed for identifying early responders to cancer therapy. To date, sampling errors due to 2D imaging has restricted DCE-US in assessing highly heterogeneous tumors. The purpose of this study was to perform a clinical assessment of 3D DCE-US feasibility and reproducibility.
Traditional B-Scan images show the envelope of received echoes as a grey scale image. The echoes are produced from specular reflections and scattering sites where changes in acoustic impedance occur (Cobbold, Foundations of Biomedical Ultrasound, Oxford Press, 2007). A long-standing area of interest concerns the frequency dependence of scatterers within different tissues, organs, and the blood.
Early detection of hepatocellular carcinoma (HCC) is critically needed to improve patient survival. Ultrasound is the first-line technology to screen patients at increased risk but has low sensitivity and specify in particular in hepatic cirrhosis. Quantitative ultrasound spectroscopy (QUS) is a promising tool that may increase diagnostic accuracy of ultrasound by enabling quantitative assessment...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.